Physiology Multiple Choice Questions
1. Regarding equilibrium potential (mammalian spinal motor neurons)
A. The resting membrane potential is – 70 mV – identical to that of Ecl
B. Equilibrium potential of potassium is +90 mV
C. Increases in external sodium concentrations decrease the resting membrane potential
D. Equilibrium potential of sodium is –60 mV
E. Na+K+ ATPase pumps 2 sodium out of cell for every 3 potassium it pumps in
Answer: A.The resting membrane potential is – 70 mV – identical to that of Ecl
2. Regarding body composition
A. 18% body weight is protein / related substances
B. 15% body weight is interstitial fluid
C. 60% body weight is water
D. 5% body weight is plasma
E. All of the above are true
Answer: E.All of the above are true
3. Regarding buffers in the body
A. Initial correction of pH disturbance is achieved by the kidneys
B. The phosphate buffer system is the predominant buffer in the blood
C. Bones contribute to buffering by taking up bicarbonate
D. Hb is an important buffer in the blood
E. All of the above are true
Answer: D.Hb is an important buffer in the blood
4. The size of the action potential is decreased by
A. Decreased extracellular calcium
B. Increased external sodium
C. Decreased internal sodium
D. Decreased internal potassium
E. Increased internal potassium
Answer: C.Decreased internal sodium
5. Regarding body fluid compartments
A. About 2/3 TBW is extracellular
B. ECF / intracellular fluid volume ratio is larger in infants than in adults
C. Plasma volume in a 70 kg male is approximately 5 litres
D. A 30 year old male has 40% water as a percentage of body weight
E. Transcellular fluid has a greater volume than intracellular fluids
Answer: B.ECF / intracellular fluid volume ratio is larger in infants than in adults
6. Fick’s Law of Diffusion is dependent on all EXCEPT
A. The posture of the subject
B. The solubility of the gas
C. Thickness of membrane barrier
D. Molecular weight of the gas
E. Area of the membrane
Answer: A.The posture of the subject
7. Regarding movement across cell membranes
A. Exocytosis requires sodium and energy
B. Insulin reuptake is by receptor mediated endocytosis
C. Thyroid hormones decrease the activity of the NaK ATPase
D. Active transport of sodium is rarely coupled with other substances
E. NaK ATPase has a 1:1 coupling ratio
Answer: B.Insulin reuptake is by receptor mediated endocytosis
8. In regard to pH
A. pH of a solution is the log to base 10 of the reciprocal hydrogen ion concentration
B. Is the negative log of the concentration of hydrogen ions
C. For each pH unit less than 7 – the concentration of hydrogen ion is increased 10 fold
D. A pH of 7 is equal to a hydrogen ion concentration of 10-7 mmol/l
E. All of the above are true
Answer: E.All of the above are true
9. Regarding heterotrimeric G proteins
A. GDP is bound to the B subunit
B. They are not serpentine receptors
C. The delta unit separates from the other subunits to bring about the biological effect
D. The intrinsic GTPase activity of the alpha subunit converts GTP to GDP
E. They span the membrane seven times
Answer: E.They span the membrane seven times
10. Which of the following is correct?
A. Chloride concentration in interstitial fluid is greater than in the plasma
B. Potassium concentration in interstitial fluid is greater than that in intracellular fluid
C. Sodium concentration in intracellular fluid is greater than in plasma
D. Protein concentration in plasma is greater than in intracellular fluid
E. Bicarbonate concentration in intracellular fluid is greater than in interstitial fluid
Answer: A.Chloride concentration in interstitial fluid is greater than in the plasma
11. Regarding basic physiological measures – all of the following are true EXCEPT
A. Osmolarity is the number of osmoles / litre of solution
B. PH is the log to base 10 of the reciprocal of hydrogen ion concentration
C. Carbon has a molecular mass of 12 dalton
D. Osmolarity is measured by freezing point depression
E. One equivalent of sodium is 23 g/l
Answer: D.Osmolarity is measured by freezing point depression
12. With regards to cell membrane potential
A. The Donnan effect relies on nondiffusible ions
B. The exterior of the cell is negative with respect to the interior
C. The membrane potential tends to push chloride out of the cell
D. It can be derived by measuring the chloride concentration and using the Nernst equation
E. Potassium leaks out against its concentration gradient
Answer: A.The Donnan effect relies on nondiffusible ions
13. Regarding the comparison of ECF with CSF – all of the following are trueEXCEPT
A. CSF has less protein
B. CSF has lower osmolality
C. CSF has lower pH
D. CSF has more bicarbonate
E. CSF has lower specific gravity
Answer: B.CSF has lower osmolality
14. Which of the following does NOT act via an intracellular receptor?
A. Cortisol
B. Thyroxine
C. ANP
D. Aldosterone
E. Retinoic acid
Answer: C.ANP
15. Regarding functional morphology of the cell
A. Tay Sachs disease is a cell membrane disorder
B. Actin is the most abundant protein in mammalian cells
C. Peroxisomes are 5 um in diameter
D. The assembly of microtubules in the cell cytoskeleton is facilitated by cold
E. Myosin 1 is present in skeletal muscle
Answer: B.Actin is the most abundant protein in mammalian cells
chapter:
Cardiovascular
16. Regarding ECG changes, which is CORRECT?
A. hypernatraemia is associated with low voltage complexes
B. the first change in hyperkalaemia is prolongation of QRS
C. with hypokalaemia, the resting membrane potential decreases
D. in hyperkalaemia, the heart stops in systole
E. in hypercalcaemia, myocardial contractility is enhanced
Answer: E.in hypercalcaemia, myocardial contractility is enhanced
17. Regarding jugular pressure waves:
A. the ‘v’ wave denotes the increased atrial pressure due to the bulging of the tricuspid valve during isovolumetric ventricular contraction
B. in tricuspid insufficiency, there is a giant ‘A’ wave with each ventricular systole
C. atrial premature beats produce an ‘A’ wave
D. the ‘v’ wave occurs during systole
E. a giant ‘C’ wave (‘cannon wave’) may be seen in complete heart block
Answer: C.atrial premature beats produce an ‘A’ wave
18. What factor does not alter cardiac output?
A. standing up
B. sleeping
C. eating
D. exercising
E. pregnancy
Answer: B.sleeping
19. What is the O2 consumption of a beating heart at rest?
A. 2ml/100g/min
B. 9ml/g/min
C. 2ml/g/min
D. 2L/100g/min
E. 9ml/100g/min
Answer: E.9ml/100g/min
20. Regarding percentages of blood volume in the body:
A. the heart has 5%
B. the pulmonary circulation has the greatest percentage
C. the venous circulation has 35%
D. the aorta has 2%
E. capillaries have 20%
Answer: D.the aorta has 2%
21. What is a biological action of endothelin?
A. dilates vascular smooth muscle
B. produces bronchodilation
C. increase GFR and renal blood flow
D. evokes positive inotropic and chronotropic effects on myocardium
E. inhibits gluconeogenesis
Answer: D.evokes positive inotropic and chronotropic effects on myocardium
22. What inhibits gene transcription for endothelin-1 secretion:
A. nitric oxide
B. angiotensin II
C. insulin
D. growth factors
E. catecholamines
Answer: A.nitric oxide
23. Regarding NO synthase:
A. it synthesises nitrous oxide from arginine
B. there are 2 isoforms
C. it is inactivated by haemoglobin
D. NOS-1 is activated by cytokines
E. NOS-2 is in endothelial cells
Answer: C.it is inactivated by haemoglobin
24. What factor dilates the arterioles?
A. decreased local temperature
B. myogenic theory of autoregulation
C. angiotensin II
D. increased discharge of noradrenergic vasomotor nerve
E. histamine
Answer: E.histamine
25. Which is NOT a baroreceptor site?
A. right atria at the entrance of SVC and IVC
B. aortic arch
C. left atria at the entrance of the pulmonary veins
D. pulmonary circulation
E. carotid body
Answer: E.carotid body
26. Regarding cerebrospinal fluid:
A. the total volume of CSF is 300mL
B. CSF is absorbed through the choroid plexus
C. the average CSF pressure is 220m-CSF
D. CSF has a higher pH than plasma
E. it contains very low levels of cholesterol relative to plasma
Answer: E.it contains very low levels of cholesterol relative to plasma
27. Which substance has equal concentrations in CSF and plasma?
A. Ca2+
B. K+
C. Na+
D. PCO2
E. glucose
Answer: C.Na+
28. Which vessel has the lowest PO2?
A. maternal artery
B. maternal vein
C. uterine vein
D. umbilical vein
E. umbilical artery
Answer: E.umbilical artery
29. During exercise:
A. diastolic BP increases more than systolic BP
B. regional blood flow to the brain doubles
C. cardiac output may increase 15-fold
D. after exercise, BP takes longer to return to normal than heart rate
E. O2 consumption of skeletal muscle may increase 100-fold
Answer: E.O2 consumption of skeletal muscle may increase 100-fold
30. Atrial systole:
A. causes a decrease in atrial pressure
B. causes the ‘A’ wave of the jugular pulse
C. causes the ‘C’ wave of the jugular pulse
D. causes the ‘V’ wave of the jugular pulse
E. causes the dicrotic notch of the aortic pulse
Answer: B.causes the ‘A’ wave of the jugular pulse
31. The depolarisation of cardiac muscle cells is characterised by:
A. a slow depolarisation, a plateau then a rapid repolarisation
B. initial depolarisation due to a slow Na+ influx
C. repolarisation due to K+ efflux through two types of K+ channels
D. a plateau phase due to slowly opening Na+ channels
E. calcium efflux during the plateau phase
Answer: D.a plateau phase due to slowly opening Na+ channels
32. Regarding cardiac electrical properties:
A. all cardiac cells have the same resting membrane potential
B. cholinergic fibres act predominantly by blocking tonic sympathetic input
C. discharge rates of pacemaker tissue does not change significantly with temperature
D. the bundle of HIS is not the most rapidly conducting part of the conducting system
E. the last parts of myocardium to depolarise normally do not include the septum
Answer: D.the bundle of HIS is not the most rapidly conducting part of the conducting system
33. Abnormalities causing ECG changes in myocardial infarction include:
A. delayed repolarisation early on
B. delayed depolarisation
C. increased resting membrane potential
D. TQ segment elevation
E. current flow away from the infarct
Answer: B.delayed depolarisation
34. Features of the venous system include all of the following EXCEPT:
A. total volume is approximately 55% of the total vascular volume
B. compliance approximately 25 times the arterial side
C. total volume of venules is twice the total capillary volume
D. valves in the cerebral circulation
E. substantial venoconstriction in response to noradrenaline
Answer: D.valves in the cerebral circulation
35. Arteriolar constriction is caused by:
A. serotonin
B. ANP
C. NO
D. K+
E. histamine
Answer: A.serotonin
36. Regarding the inputs into the vasomotor centre:
A. baroreceptors causes stimulation
B. chemoreceptors cause inhibition
C. baroreceptors provide significant input below 70mmhg mean arterial pressure
D. atrial stretch receptors inhibit the vasomotor centre
E. direct inputs include pO2
Answer: D.atrial stretch receptors inhibit the vasomotor centre
37. CSF:
A. volume is about 600ml
B. normal pressure is 5-10cm CSF
C. has a higher concentration of creatinine than plasma
D. has a higher concentration of urea than plasma
E. is formed solely in the choroid plexus
Answer: C.has a higher concentration of creatinine than plasma
38. Regarding the conduction system of the heart:
A. the right bundle branch (of HIS) divides into anterior and posterior fasicles
B. the AV node contains P cells
C. myocardial fibres have a resting membrane potential of -60mV
D. action potential in the SA and AV nodes are largely due to Na+ influx
E. there are two types of K+ channels in pacemaker tissue – transient and long acting
Answer: B.the AV node contains P cells
39. During systole:
A. the peak left ventricular pressure is 160mmHg
B. contraction of the atria propels 70% of the ventricular filling
C. the period of isovolumetric ventricular contraction is 0.5sec????
D. the end systolic ventricular volume is about 50mL
E. coronary blood flow to subendocardial portions of the left ventricle occur only in systole
Answer: D.the end systolic ventricular volume is about 50mL
40. Regarding cardiac output:
A. “energy of contraction is proportional to the initial length of the cardiac muscle fibre” is Fick’s Law of the heart
B. cardiac index is the correlation between resting cardiac output and height
C. sleep decreases cardiac output
D. basal O2 consumption by the myocardium is 2ml/g/min
E. standing normally decreases the length of ventricular cardiac muscle fibres
Answer: E.standing normally decreases the length of ventricular cardiac muscle fibres
41. Effects of electrolyte changes:
A. PR interval increases in hyperkalaemia
B. in hyperkalaemia, the heart stops in systole
C. hypercalcaemia causes prolongation of the ST segments
D. hypernatraemia is associated with low voltage electrocardiographic complexes
E. magnesium counteracts digitalis toxicity
Answer: E.magnesium counteracts digitalis toxicity
42. Which statement is TRUE regarding cardiac muscle?
A. cardiac muscle fibres are multinucleated
B. they are smaller than skeletal muscle fibres
C. Ca2+ release is triggered by membrane repolarisation
D. the elastic ‘Titin” protein component is greater than in skeletal muscle, adding stiffness
E. the amount of Ca2+ in the sarcoplasmic reticulum is decreased by catecholamine stimulation
Answer: B.they are smaller than skeletal muscle fibres
43. Which statement regarding cardiac “work” is FALSE?
A. the energy applied to the blood stream is defined as kinetic plus potential
B. potential energy involves consideration of energy stored in elastic arterial walls and gravity
C. there is an exchange between kinetic and potential energy
D. the largest drop in energy occurs at the level of the precupillary sphincters
E. the higher resistance in smaller calibre vessels corresponds to greater energy losses
Answer: D.the largest drop in energy occurs at the level of the precupillary sphincters
44. Which statement about blood flow is FALSE?
A. cardiac output = stroke volume x heart rate
B. the volume of blood pumped through the lungs equals the volume entering the heart
C. Poiseville’s Law predicts the effects of pressure and resistance on cardiac output
D. the resistance of the systemic circulation is 5 to 10 times the pulmonary vascular resistance
E. with constant pressure, a vessel with radius ‘2X ‘ has 16 times the flow of vessel with radius ‘X’
Answer: B.the volume of blood pumped through the lungs equals the volume entering the heart
45. Regarding haemodynamic principles, which statement is FALSE?
A. viscosity of blood with haematocrit of 40 is three times that of water
B. ‘arterial’ blood volume is 10-15% total volume
C. ‘elastance’ measures a vessel’s stiffness or recoil
D. aging causes increased elastance and therefore decrease in resting (unstressed) arterial volume
E. an increase in total peripheral resistance leads to increased arterial volume and BP
Answer: D.aging causes increased elastance and therefore decrease in resting (unstressed) arterial volume
46. Considering conduction rates in myocardial cells, which statement is TRUE?
A. Perkinje fibres are subepicardial and are the largest fibres, 4-7 times the width of other fibres
B. Perkinje fibres are ‘fast fibres’, and can conduct a wave of depolarisation at a speed of 4m/sec
C. the duration of the action potential and refractory period in fast fibres is shorter than slow fibres
D. initial depolarisation occurs in fast fibres with a rapid influx of Ca2+ ions from the sarcoplasmic reticulum
E. none of the above statements are true
Answer: B.Perkinje fibres are ‘fast fibres’, and can conduct a wave of depolarisation at a speed of 4m/sec
47. With respect to splanchnic circulation:
A. the liver is approximately 50% blood by volume
B. zone 3 of the hepatic acinus is well oxygenated
C. abdominal viscera receive at 30% cardiac output
D. liver receives blood from hepatic artery (1000???ml/min) and hepatic ??? vein (500ml/min)
E. muscular layer of intestinal wall has higher flow of mucosal layer
Answer: C.abdominal viscera receive at 30% cardiac output
48. Blood pressure:
A. the sounds of Korotkoff when taking blood pressure are caused by laminar flow
B. the diastolic pressure in resting adults correlates to the muffling of Korotkoff sound
C. pressures obtained by palpation of auscultation methods are usually 2-5mmHg higher
D. if cuff is inflated for some time, it can give falsely low BP readings
E. sounds of Korotkoff occur when velocity of flow through constriction exceeds critical velocity
Answer: E.sounds of Korotkoff occur when velocity of flow through constriction exceeds critical velocity
49. Coronary circulation:
A. left coronary artery has greater flow in 50% of people
B. thebesian veins connect arterioles to the heart chambers
C. cusps of the aortic valve occlude orifices of coronary arteries during LV ejection
D. coronary flow at rest is 250ml/min
E. at rest, heart extracts 50% O2 / unit of blood delivered
Answer: D.coronary flow at rest is 250ml/min
50. Which statement is FALSE regarding CVS?
A. the primary function of the CVS uses convection
B. secondary function involves heat control
C. the heart is two pumps operating in parallel
D. the same volume of blood passes through each semilunar valve over time
E. the Frank Starling mechanism is used in balancing the output of both ventricles
Answer: C.the heart is two pumps operating in parallel
51. Regarding the heart, which is TRUE?
A. the right and left ventricles perform the same amount of work, because the same volume of blood is pumped by each
B. the cross sectional shape of both ventricles is approximately cylindrical
C. the right ventricle pumps by a bellows type mechanism
D. the left ventricle pump action is via reducing cross-sectional area, as a function of radius cubed
E. in pulmonary disease the right ventricle hypertrophies and assumes a crescented shape in cross section
Answer: C.the right ventricle pumps by a bellows type mechanism
52. Which is FALSE? Stroke Volume varies with changes in:
A. ventricular contractility
B. arterial pressure
C. end diastolic volume of ventricle
D. blood viscosity
E. right ventricle compared to left
Answer: E.right ventricle compared to left
53. Regarding pressure in circulation, which is FALSE?
A. kinetic energy = M.V2(mass x velocity2)2
B. hydrostatic (gravitational) pressure = potential energy
C. the pressure in a foot vein may be 150 cm??? greater than at aortic root (in upright posture)
D. the same pressure differential applies in arterial system, (in upright posture)
E. the greatest pressure drop occurs in the capillaries
Answer: E.the greatest pressure drop occurs in the capillaries
54. Regarding volumes in each compartment, which is FALSE?
A. 3% in LV and aorta
B. 15% in arterial system
C. 7% in capillaries
D. 50% in venous system (systemic)
E. 40% in pulmonary circulation
Answer: E.40% in pulmonary circulation
55. Regarding pressures, which is FALSE?
A. lateral (static) pressure is reduced but prolonged by elastic arteries
B. static pressure increases with gravitation (hydrostatic) pressure increases
C. static pressure does not include kinetic energy
D. greater resistance to flow through a segment of circulation leads to greater loss of energy through that segment
E. kinetic energy becomes more significant in a narrowed segment and converts back to potential energy when the tube widens
Answer: B.static pressure increases with gravitation (hydrostatic) pressure increases
56. Regarding flow, which is FALSE?
A. flow is proportional to pressure gradient
B. flow is inversely proportional to resistance
C. Poiseville’s Law relates flow to pressure gradient and factors that influence resistance
D. Poiseville’ Law demonstrates that resistance to flow is largely determined by viscosity and length of tube and radius x 4
E. if radius of a vessel is halved, the flow may be reduced to 1/16th of previous flow
Answer: D.Poiseville’ Law demonstrates that resistance to flow is largely determined by viscosity and length of tube and radius x 4
57. Which statement about factors affecting blood pressure is FALSE? Factors that increase blood pressure are:
A. increased heart rate
B. increased blood volume
C. pressure rises in increased cardiac output until the amount entering the arterial system equals the amount leaving
D. increased total peripheral resistance
E. increased end systolic volume
Answer: E.increased end systolic volume
58. Regarding blood pressure, which is TRUE?
A. M.A.P. = pulse pressure / 2 + diastolic pressure
B. elastance increases progressively with age
C. increase in arterial blood pressure causes a subsequent increase in stroke volume
D. increased sympathetic stimulation may sometimes lead to decreased cardiac output
E. pulse pressure increases with age because of decreased arterial elastance
Answer: B.elastance increases progressively with age
59. Regarding red blood cells, all are true EXCEPT:
A. erythropoiesis is stimulated by anaemia and hypoxia
B. after splenectomy, malaria has a higher mortality
C. normal adult haemoglobin is designated α2 β2
D. about 5% of adult haemoglobin is haemoglobin A2 (α2 δ2)
E. G6PD deficiency increases red cell susceptibility to lysis by drugs and infection
Answer: D.about 5% of adult haemoglobin is haemoglobin A2 (α2 δ2)
60. Regarding the function of the heart:
A. at increased heart rates, diastole is shortened more than systole
B. the pericardial sac normally contains about 50ml of fluid
C. during the cardiac cycle, left ventricular ejection begins before right ventricular ejection
D. during expiration, the aortic valve closes before the pulmonary valve
E. the end—diastolic ventricular volume is about 170ml
Answer: A.at increased heart rates, diastole is shortened more than systole
61. Regarding flow in vessels:
A. velocity is greatest closest to blood vessel walls
B. turbulence is almost always present at a Reynold’s number greater than 2,000
C. probability of turbulence in a vessel is directly related to twice the radius
D. flow in vessels is directly related to the fourth power of the ?????
E. turbulence is related to increasing radius
Answer: C.probability of turbulence in a vessel is directly related to twice the radius
62. Which of the following does not increase the length of ventricular cardiac muscle fibres?
A. increased total blood volume
B. increased venous tone
C. increased pumping action of skeletal muscle
D. increased negative intrathoracic pressure
E. increased intrapericardial pressure
Answer: E.increased intrapericardial pressure
63. Which of the following does not cause a systolic murmur?
A. aortic stenosis
B. anaemia
C. mitral insufficiency
D. tricuspid stenosis
E. normal flow in children
Answer: D.tricuspid stenosis
64. Timing of events in the cardiac cycle:
A. right atrial systole begins after left atrial systole
B. the pulmonary closes after the aortic in inspiration
C. right ventricular ejection starts after left ventricular ejection
D. right ventricular systole starts after left ventricular systole
E. right and left atrial systole are synchronous
Answer: B.the pulmonary closes after the aortic in inspiration
65. Starling’s Law of the heart:
A. is an example of hetermeric regulation
B. is an example of homomeric regulation
C. is explained by troponin / tropomyosin overlap
D. relates stroke volume to cardiac output
E. bears little relation to in vivo regulation of the heart
Answer: A.is an example of hetermeric regulation
66. The least frequent “ABO” gene is:
A. A
B. B
C. O
D. AB
E. ABO
Answer: B.B
67. Stimulation of the right vagus:
A. increases calcium inflow to the SA node
B. decreases calcium inflow to the AV node
C. increases potassium outflow in the SA node
D. increases potassium outflow in the AV node
E. decreases potassium outflow in the SA node
Answer: C.increases potassium outflow in the SA node
68. Starling’s Law:
A. defines a linear relationship between wall tension and force of contraction of cardiac muscle
B. is approximated by representing wall tension as preload and force of contraction as afterload
C. predicts greater force of contraction when filling pressure is decreased (eg during shock)
D. is explained by an increased availability of intracellular Ca2+
E. describes heterometric autoregulation
Answer: E.describes heterometric autoregulation
chapter:
Endocrine and Gastrointestinal Tract
69. Which is a water soluble vitamin?
A. D
B. B12
C. A
D. K
Answer: B.B12
70. Which is not Na+ dependent for absorption?
A. thiamin
B. riboflavin
C. niacin
D. folate
Answer: D.folate
71. Which is absorbed mainly in the colon?
A. short chain fatty acids
B. calcium
C. vitamin K
D. oligosaccharides
Answer: A.short chain fatty acids
72. Which is INCORRECT regarding nerve supply to the gut?
A. the blood vessels are known to have enteric, parasympathetic and sympathetic innervation
B. the myenteric plexus lies between the longitudinal and circular muscle layers
C. parasympathetic supply is via vagal and sacral nerve
D. sympathetic supply is often inhibitory on cholinergic postganglionic fibres
Answer: A.the blood vessels are known to have enteric, parasympathetic and sympathetic innervation
73. Gastrin secretion is stimulated by all but:
A. luminal peptides
B. vagal discharge
C. luminal acid
D. phenylalanine
Answer: C.luminal acid
74. The actions of gastrin include all but:
A. insulin secretion in response to a carbohydrate meal
B. a trophic effect on colonic mucosa
C. a trophic effect on gastric mucosa
D. pepsin secretion
Answer: A.insulin secretion in response to a carbohydrate meal
75. Which is NOT an action of CCK?
A. gallbladder contraction
B. increased gastric motility and emptying
C. glucagon secretion
D. secretion of pancreatic juice
Answer: B.increased gastric motility and emptying
76. Which hormone is most important in insulin secretion?
A. gastrin
B. CCK
C. GIP
D. secretin
Answer: C.GIP
77. Which produces the majority of salivary volume?
A. lingual glands
B. sublingual
C. parotid
D. submandibular
Answer: D.submandibular
78. Which nerve is NOT involved in the efferent (motor) swallow reflex?
A. trigeminal
B. vagus
C. facial
D. hypoglossal
Answer: B.vagus
79. Which is NOT part of the normal content of gastric juice?
A. HPO4 2-
B. mucus
C. lipase
D. amylase
Answer: D.amylase
80. Chief cells secrete:
A. HCl
B. pepsinogen
C. intrinsic factor
D. HCO3-
Answer: B.pepsinogen
81. Which stimulates parietal cell secretion?
A. prostaglandins
B. aspirin
C. vinegar
D. acetylcholine
Answer: D.acetylcholine
82. Regarding bilirubin:
A. unconjugated bilirubin is more soluble than conjugated
B. all conjugated bilirubin is excreted via the intestine
C. bile duct obstruction causes jaundice secondary to unconjugated hyperbilirubinaemia
D. haemolytic anaemia may cause ?????? hyperbilirubinaemia
Answer: D.haemolytic anaemia may cause ?????? hyperbilirubinaemia
83. Which form of intestinal smooth muscle contraction does NOT occur in normal health?
A. peristalsis
B. weak antiperistalsis
C. peristaltic rushes
D. tonic contractions
Answer: C.peristaltic rushes
84. In the adrenal medulla:
A. epinephrine is formed by the hydroxylation and decarboxylation of tyrosine
B. 10% of the cells are the epinephrine-secreting type
C. plasma norepinephrine levels are generally unchanged after adrenalectomy
D. catecholamine t1/2 is 10 minutes in the circulation
Answer: C.plasma norepinephrine levels are generally unchanged after adrenalectomy
85. In the adrenal cortex:
A. the zona glomerulosa has 17 alpha-hydroxylase and no aldosterone synthase
B. all the cholesterol is synthesised from acetate
C. zona fasciculata makes up 10% of the mass of the adrenal gland
D. angiotensin II binds to receptors in the zona reticularis
Answer: E.
86. Regarding the islets of Langerhans:
A. D cells secrete pancreatic polypeptide
B. A cells are the most common
C. they are most plentiful in the body of the pancreas
D. blood from the islets drain into the hepatic portal vein
Answer: D.blood from the islets drain into the hepatic portal vein
87. Which factor stimulates insulin secretion?
A. thiazide diuretics
B. phenytoin
C. theophylline
D. β blockers
Answer: C.theophylline
88. Thyroid hormones increase the oxygen consumption of:
A. lymph nodes
B. spleen
C. brain
D. anterior pituitary gland
Answer: E.
89. The action of gastrin includes all EXCEPT:
A. stimulation of insulin secretion after a carbohydrate meal
B. stimulation of gastric acid secretion
C. stimulation of gastric motility
D. contraction of gastro-oesophageal junction musculature
Answer: A.stimulation of insulin secretion after a carbohydrate meal
90. Regarding protein metabolism, which statement is CORRECT?
A. increases the respiratory quotient to values > 1.0
B. has a specific dynamic action (SDA) of approximately 10%
C. endogenous protein breakdown is inhibited by glucagon
D. creatinine excretion is not depressed in starvation
Answer: D.creatinine excretion is not depressed in starvation
91. Regarding fat metabolism, which statement is CORRECT?
A. ketone bodies accumulate in DKA due to a lack of acetyl-CoA substrate
B. fatty acids are transported in the plasma bound to lipoprotein complexes
C. cholesterol is transported from extra-hepatic cells to the liver by high-density lipoproteins (HDLs) in the endogenous pathway
D. eicosanoids are synthesised from cholesterol
Answer: C.cholesterol is transported from extra-hepatic cells to the liver by high-density lipoproteins (HDLs) in the endogenous pathway
92. Thyroxine:
A. is mostly bound to albumin in the plasma, since this has the largest capacity
B. is 2-5 times more potent that triiodothyronine (T3)
C. stimulates TSH release
D. ∼33% is deiodinated in the liver to T3
Answer: D.∼33% is deiodinated in the liver to T3
93. Insulin:
A. binds to GLUT 1-5 receptors in the peripheral tissues
B. deficiency results in increased gluconeogenesis
C. has a plasma half-life of 2-3 hours
D. is secreted by the pancreatic A cells
Answer: E.
94. With respect to calcium metabolism / bone formation:
A. osteoclasts secrete alkaline phosphatase
B. osteoblasts are haemopoietic derivatives of monocyte lineage
C. 1,25(OH)2 ???D3 and PTH stimulate both osteoblasts and osteoclasts
D. oestrogens are thought to be protective of osteoporosis as their main effect is osteoblasts stimulation
Answer: C.1,25(OH)2 ???D3 and PTH stimulate both osteoblasts and osteoclasts
95. All of the following, except one, inhibit insulin secretion. Which is it?
A. somatostatin
B. thiazide diuretics
C. propranolol
D. insulin
Answer: E.
96. All but one of the following compounds releases large amounts of energy on breakdown:
A. cAMP
B. ATP
C. creatine phosphate
D. ADP
Answer: A.cAMP
97. Which is TRUE?
A. adenosine triphosphate is a low energy phosphate
B. reduction involves loss of hydrogen or electrons
C. oxidative phosphorylation occurs in the endoplasmic reticulum
D. ATP is precursor of cyclic AMP
Answer: D.ATP is precursor of cyclic AMP
98. Small intestine:
A. the ligament of Treitz the jejunum becomes the ileum
B. the distance pylorus to ileocecal valve in living humans is 700cm
C. malabsorption syndrome may develop if 25% of the small intestine is removed
D. colonic peristalsis is the first smooth muscle action of the GIT to return after abdominal operation
Answer: E.
99. Regarding thyroid hormones:
A. little T3 is produced peripherally by deiodination T4
B. albumin has more capacity to bind thyroid hormones than TBG
C. TBG has less affinity for thyroid hormone than albumin
D. thyroid hormones stimulate lipogenesis
Answer: B.albumin has more capacity to bind thyroid hormones than TBG
100. A calorie is:
A. standard unit of heat energy necessary to raise the temperature of 1L of water 1° from 15-16°C
B. standard unit of heat energy necessary to raise the temperature of 1gm of mercury 1° from 17-18°C
C. the standard unit of heat energy necessary to raise the temperature of 1gm of water 1° from 17-18°C
D. the standard unit of heat energy necessary to raise the temperature of 1gm of water 1° from 15-16°C
Answer: D.the standard unit of heat energy necessary to raise the temperature of 1gm of water 1° from 15-16°C
101. Regarding the respiratory quotient:
A. it is the ratio of CO2 to O2 at any time
B. RQ of fat is 0.8
C. increases with hyperventilation
D. increases in metabolic alkalosis
Answer: E.
102. Regarding basal metabolic rate:
A. it is higher in women
B. it is determined at rest within 12 hours after the last meal
C. increases by 18% for each 1°C of fever
D. is about 40Kcal/m2/h in an average man
Answer: D.is about 40Kcal/m2/h in an average man
103. Which is NOT a high energy compound?
A. CoA
B. GGP
C. ITP
D. creatine phosphate
Answer: B.GGP
104. Regarding carbohydrate metabolism:
A. glucokinase is increased in starvation
B. the breakdown of glycogen is called glycolysis
C. the direct oxidative pathway involves the breakdown of glucose through triose
D. the conversion of pyruvate to acetyl-CoA is irreversible
Answer: D.the conversion of pyruvate to acetyl-CoA is irreversible
105. Which is NOT produced by the citric acid cycle?
A. NAD+
B. CO2
C. GTP
D. FADH2
Answer: A.NAD+
106. Regarding phosphorylase:
A. it clea???? 1:6α linkages in glycogen
B. it is activated by norepinephrine
C. phosphorylase kinase is directly activated by cyclic AMP
D. activation of protein kinase A inhibits glycogen synthesis
Answer: D.activation of protein kinase A inhibits glycogen synthesis
107. Which amino acid is not found in protein?
A. ornithine
B. arginine
C. valine
D. aspartic acid
Answer: E.
108. Regarding electrolyte absorption:
A. cholera toxin binds to adenosine diphosphate ribose to the subunit of Gs, stimulative ATPase activity
B. active transport of Na+ into the small intestine enterocytes is coupled with the absorption of glucose
C. magnesium sulphate absorption is coupled with Na+ -K+ -ATPase pump
D. the Na+ -K+ ATPase pumps are located at the luminal membrane of the enterocyte
Answer: E.
chapter:
GI-Digestion-Absorption-Metabolism
109. Vitamins co-transported with Na+ include all EXCEPT:
A. thiamine
B. folate
C. niacin
D. riboflavin
E. pyridoxine
Answer: B.folate
110. Fat soluble vitamins include all EXCEPT:
A. vitamin A
B. vitamin C
C. vitamin D
D. vitamin E
E. vitamin K
Answer: B.vitamin C
111. The largest daily volume of secretions in the GIT originates in the:
A. salivary glands
B. stomach
C. gallbladder (bile)
D. pancreas
E. intestine
Answer: B.stomach
112. Iron:
A. most dietary iron is in the ferrous state
B. most iron is absorbed in the upper small intestine
C. a ferritin micelle contains 1,000 atoms of iron
D. 90% of body iron is in haemoglobin
E. 10% of dietary iron is normally absorbed
Answer: B.most iron is absorbed in the upper small intestine
113. Ketone bodies:
A. are not formed under normal conditions
B. are all moderately strong acids
C. are formed when intracellular glucose is deficient
D. are easily metabolised in the liver
E. all of the above
Answer: C.are formed when intracellular glucose is deficient
114. Creatinuria can occur in all EXCEPT:
A. healthy children
B. pregnant women
C. starvation
D. hypothyroidism
E. poorly controlled diabetes mellitus
Answer: D.hypothyroidism
115. Cations in normal (fasting) gastric juice include all EXCEPT:
A. Na+
B. Ca++
C. K+
D. Mg++
E. H+
Answer: B.Ca++
116. Human hepatic bile (hepatic bile duct) is largely:
A. water
B. bile salts
C. bile pigment
D. cholesterol
E. lecithin
Answer: A.water
117. The nutritionally essential amino acids include:
A. alanine
B. cysteine
C. tyrosine
D. methionine
E. glutamine
Answer: D.methionine
118. The largest glycogen store in the adult body is in the:
A. liver
B. spleen
C. muscle
D. pancreas
E. circulating red cell mass
Answer: C.muscle
119. TSH secretion is stimulated by:
A. dopamine
B. somatostatin
C. cold temperatures
D. stress
E. glucocorticoids
Answer: C.cold temperatures
120. Thyroxine (T4) has greater affinity for:
A. thyroxine-binding globulin
B. transthyretin
C. thyroxine-binding pre-albumin
D. albumin
E. triiodothyronine
Answer: A.thyroxine-binding globulin
121. GLUT is an example of:
A. simple diffusion
B. facilitated diffusion
C. primary active transport
D. secondary active transport
E. endocytosis
Answer: B.facilitated diffusion
122. The most common cell type of the endocrine pancreas is:
A. A cells
B. B cells
C. C cells
D. D cells
E. F cells
Answer: B.B cells
123. Both insulin and somatostatin:
A. are released from extra-pancreatic sites
B. receptors are linked to G proteins
C. inhibit release of glucagon
D. cause K+ uptake by cells
E. are polypeptides containing two chains linked by disulphide bonds
Answer: C.inhibit release of glucagon
124. Aldosterone is secreted by:
A. zona reticularis
B. zona fasciculata
C. zona glomerulosa
D. zona fasciculata and reticularis
E. zona glomerulosa and fasciculata
Answer: C.zona glomerulosa
125. Regarding aldosterone:
A. it is released in response to hypokalaemia
B. it has glucocorticoid action
C. it works via G proteins to increase Na+ reabsorption
D. its release results in alkaline urine
E. it is highly protein-bound
Answer: B.it has glucocorticoid action
126. Calcitonin secretion is increased by:
A. gastrin
B. CCK
C. secretin
D. glucagon
E. all of the above
Answer: E.all of the above
127. All of the following bind to intracellular receptors EXCEPT:
A. cortisol
B. aldosterone
C. 1,25-DHCC
D. parathyroid hormone
E. thyroxine
Answer: D.parathyroid hormone
128. How many trophic hormones does the anterior pituitary produce?
A. 2
B. 3
C. 5
D. 6
E. 8
Answer: C.5
129. All of the following are high energy phosphate compounds EXCEPT:
A. adenosine triphosphate
B. glucose 6-phosphate
C. creatine phosphate
D. adenosine diphosphate
E. guanosine triphosphate
Answer: B.glucose 6-phosphate
130. Under aerobic conditions, 1mol glucose forms:
A. 2mol ATP
B. 8mol ATP
C. 16mol ATP
D. 38mol ATP
E. 42mol ATP
Answer: D.38mol ATP
131. The approximate ratio of fat : CHO energy stores is:
A. 2 : 1
B. 4 : 1
C. 10 : 1
D. 20 : 1
E. 40 : 1
Answer: E.40 : 1
132. Nutritionally essential amino acids include:
A. glycine
B. serine
C. lysine
D. glutamine
E. tyrosine
Answer: C.lysine
133. Uric acid is formed by the breakdown of:
A. purines
B. pyrimidines
C. glutamine
D. urea
E. all of the above
Answer: A.purines
134. The LDL contains which aproprotein?
A. A
B. B-48
C. B-100
D. C
E. E
Answer: C.B-100
135. Regarding cellular metabolism of cholesterol:
A. it inhibits HMG-CoA red???
B. is processed in part to other cholesterol esters by the enzyme acetyl CoA ??? acyltransferase
C. it inhibits the formation of CO2 receptors
D. all of the above
E. none of the above
Answer: D.all of the above
136. Which of the following substances decreases the activity of hormone-sensitive lipase?
A. adrenaline
B. thyroxine
C. serotonin
D. TSH
E. prostaglandin E
Answer: E.prostaglandin E
137. Chromium deficiency leads to:
A. insulin resistance
B. hypogondal dwarfism
C. anaemia
D. changes in ossification
E. thyroid disorder
Answer: A.insulin resistance
138. Vitamin B1 (thiamine) deficiency leads to:
A. anaemia
B. beri beir
C. convulsions
D. dermatitis
E. pellagra
Answer: B.beri beir
chapter:
Nervous System
139. Which of the following phosphate compounds is MOST important in the production ofenergy?
A. AMP (adenosine monophosphate)
B. ADP (adenosine diphosphate)
C. ATP (adenosine triphosphate)
D. GTP (guanosine triphosphate)
E. CTP (cytidine triphosphate)
Answer: C.ATP (adenosine triphosphate)
chapter:
Metabolism and Endocrinology
140. Which of the following is NOT produced by the citric acid cycle?
A. CO2
B. H+ ions
C. NAD+
D. GTP (guanosine triphosphate)
E. NADH
Answer: C.NAD+
141. The renal threshold for glucose, the arterial blood level at which glycosuria appears,is approximately:
A. 1.8g/dL
B. 180mg/dL
C. 18mg/dL
D. 80mg/dL
E. 800mg/dL
Answer: B.180mg/dL
142. Which of the following amino acids are glucogenic (ie give rise to compounds readilyconverted to glucose)?
A. alanine
B. leucine
C. isoleucine
D. phenylalanine
E. tyrosine
Answer: A.alanine
143. Which of the following lipoproteins is SMALLEST in size?
A. chylomicrons
B. very low density lipoproteins
C. intermediate density lipoproteins
D. low density lipoproteins
E. high density lipoproteins
Answer: E.high density lipoproteins
144. Regarding the respiratory quotient, which of the following is TRUE?
A. it is the ratio of CO2 and O2 in the body at any one time
B. can go as high as 2.00 because lactic acid produces more oxygen
C. in acidosis, it goes down
D. in alkalosis it goes up
E. it is possible for it to be negative
Answer: E.it is possible for it to be negative
145. Regarding body surface area, which of the following statements is TRUE?
A. is calculated using weight/height
B. is calculated using 0.007184 X weight + 0.425 X weight + 0.725
C. it does not affect the basal metabolic rate
D. it does not affect the general metabolic rate
E. it has an effect on the specific dynamic action of foodstuffs
Answer: B.is calculated using 0.007184 X weight + 0.425 X weight + 0.725
146. Regarding the basal metabolic rate, which of the following is TRUE?
A. it is measured in the absence of disease, at room temperature, within 12 hours of a meal with a Benedict apparatus and the subject asleep
B. it increases 24% per degree Celsius of body temperature above 37°
C. it is decreased during the latter stage of starvation, explaining the initial rapid weight loss than a slowing down of weight loss
D. it declines in pregnancy
E. it correlates closer to weight than to body surface area
Answer: C.it is decreased during the latter stage of starvation, explaining the initial rapid weight loss than a slowing down of weight loss
147. Biological energy can be derived from all EXCEPT:
A. lactic acid
B. phosphorylcreatine
C. guanosine triphosphate
D. co enzyme A
E. urea
Answer: E.urea
148. Regarding brown fat, which of the following is TRUE?
A. it is fat with a large percentage of melatonin as a constituent
B. it has extensive parasympathetic innervation
C. it is more abundant in adults than in infants
D. heat production is assisted by uncoupling of the H+ /ATP generator system in mitochondria
E. brown fat cells contain multiple droplets of fat
Answer: A.it is fat with a large percentage of melatonin as a constituent
149. Regarding thyroid hormones, which statement is INCORRECT?
A. thyroid hormones bind to receptors in cell nuclei
B. T3 is less potent than T4
C. thyroid hormones increase O2 consumption
D. T3 promotes nitrogen excretion
E. cerebral glucose consumption is increased by thyroid hormones
Answer: B.T3 is less potent than T4
150. Regarding thyroxine, which of the following is INCORRECT?
A. increases number of β adrenergic receptors on the heart
B. there is a preferential expression of α myosin in the muscle fibres of the heart in the presence of thyroxine
C. thyroid hormones decrease carbohydrate absorption by the stomach and small bowel
D. hyaluronic acid accumulates in the skin if there is a deficiency of thyroxine
E. large doses can increase body temperature
Answer: C.thyroid hormones decrease carbohydrate absorption by the stomach and small bowel
151. Regarding the respiratory quotient, which of the following is TRUE?
A. it is the ratio of CO2 produced to the volume of O2 consumed per unit of time
B. is related to tidal volume
C. is inversely proportioned to pO2
D. has a value of 2.3 for fats
E. varies with age
Answer: A.it is the ratio of CO2 produced to the volume of O2 consumed per unit of time
152. Which of the following statements is INCORRECT?
A. in a low protein diet, nitrogen excretion by the kidney decreases
B. in a low protein diet, the maximal urine osmolarity is decreased
C. there is a net negative nitrogen balance following the administration of steroids
D. nitrogen balance becomes negative if a single amino acid is missing from the diet
E. insulin spares the breakdown of muscle protein
Answer: C.there is a net negative nitrogen balance following the administration of steroids
153. Which of the following is an ESSENTIAL fatty acid?
A. myristic acid
B. palmitic acid
C. stearic acid
D. linolenic acid
E. oleic acid
Answer: D.linolenic acid
154. Regarding protein metabolism in starvation, which statement is INCORRECT?
A. glucose has a protein sparing effect by increasing insulin secretion
B. death occurs when protein depletion reaches 50% of normal level
C. total starvation leads to loss of up to 5gms/day of urea nitrogen due to protein catabolism
D. most protein catabolised comes from the liver, spleen and skeletal muscles
E. rapid protein depletion is the terminal phase once fat stores have been almost totally catabolised
Answer: C.total starvation leads to loss of up to 5gms/day of urea nitrogen due to protein catabolism
155. Which of the following is NOT an unsaturated fatty acid?
A. oleic acid
B. arachidonic acid
C. linoleic acid
D. linolenic acid
E. stearic acid
Answer: E.stearic acid
156. Regarding brown fat, which statement is INCORRECT?
A. fat cells have extensive parasympathetic innervation
B. responsible for part of the post-prandial heat production
C. fat cells contain several droplets of fat
D. prominent between and around the scapulae of infants
E. fat cells contain many mitochondria
Answer: A.fat cells have extensive parasympathetic innervation
157. Regarding carbohydrate metabolism in starvation, which statement is INCORRECT?
A. hepatic glycogenolysis precedes skeletal muscle glycogenolysis
B. blood glucose falls less in women due to greater fat stores
C. glycogen stores are exhausted after half to one day
D. blood glucose level is maintained above a level that would produce symptomatic hypoglycaemia
E. skeletal muscle contains about four times as much glycogen as the liver
Answer: B.blood glucose falls less in women due to greater fat stores
158. Regarding lipoproteins, which statement is INCORRECT?
A. VLDL transport cholesterol formed in liver to extrahepatic tissues
B. chylomicrons can cause post-prandial plasma to appear milky
C. LDL are taken up by macrophages
D. oestrogens increase plasma HDL levels
E. elevated IDL levels predispose to atherosclerosis
Answer: A.VLDL transport cholesterol formed in liver to extrahepatic tissues
159. Which of the following does NOT increase the activity of intracellular hormonesensitive lipase?
A. GH
B. PGE
C. thyroxine
D. glucagon
E. cortisol
Answer: B.PGE
160. Which of the following causes a positive nitrogen balance?
A. increased cortisol secretion
B. starvation
C. decreased insulin secretion
D. forced immobilisation
E. increased testosterone secretion
Answer: E.increased testosterone secretion
161. Which statement regarding lipoprotein lipase is INCORRECT?
A. it is not hormone sensitive
B. it requires heparin as a co-factor
C. it is confined to adipose tissue
D. its activity is decreased by stress
E. it clears chylomicrons and VLDL from circulation by degradation of triglyceride
Answer: C.it is confined to adipose tissue
162. Regarding uric acid, which statement is INCORRECT?
A. the majority of filtered uric acid is reabsorbed in the proximal tubule
B. xanthine oxidase catalyses its synthesis
C. may be elevated in leukaemia and pre-eclampsia
D. does not undergo renal tubular secretion
E. its excretion rate can be halved by changing to a purine-free diet
Answer: D.does not undergo renal tubular secretion
163. Regarding ketone bodies, which statement is INCORRECT?
A. formed following ingestion of a high fat/low carbohydrate diet
B. acetoacetate and beta-hydroxybutyrate formation leads to a metabolic acidosis
C. acetone is excreted in the urine
D. readily metabolised by the liver
E. acetone formation leads to ketotic breath
Answer: D.readily metabolised by the liver
164. Nucleotide breakdown releases purines and pyrimidines. Which of the following is NOT their subsequent fate?
A. re-used to form nucleosides, nucleotides and nucleic acids
B. excreted unchanged in urine
C. directly enter the urea cycle
D. pyrimidines are catabolised to carbon dioxide and ammonia
E. purines are catabolised to uric acid
Answer: C.directly enter the urea cycle
165. How many ATP molecules are produced from one molecule of a 6-carbon fatty acid metabolised via the TCA cycle to carbon dioxide and water?
A. 36
B. 38
C. 40
D. 42
E. 44
Answer: E.44
166. Which of the following is NOT a purine?
A. adenine
B. cytosine
C. guanine
D. hypoxanthine
E. xanthine
Answer: B.cytosine
167. Creatinine appears in the urine in significant amounts in all of the following EXCEPT:
A. normal men
B. thyrotoxicosis
C. post-partum
D. poorly controlled diabetes mellitus
E. children
Answer: A.normal men
168. Regarding free fatty acids, which statement is INCORRECT?
A. circulate in plasma bound to globulin
B. they are the major source of energy for cardiac muscle
C. combine with glycerol to form the triglyceride of neutral fat
D. contain an even number of carbon atoms
E. require linkage to carnitine in order to cross mitochondrial membranes prior to oxidation
Answer: A.circulate in plasma bound to globulin
169. Which amino acid is NOT ketogenic (ie CAN’T be converted into acetoacetate)?
A. leucine
B. isoleucine
C. phenylalanine
D. tyrosine
E. proline
Answer: E.proline
170. Regarding cholesterol, which statement is INCORRECT?
A. dietary cholesterol is absorbed in the intestine and incorporated into chylomicrons formed in the mucosa
B. about 20% is in the plasma, with the remainder intracellular
C. negatively feeds back on its synthetic pathway
D. most hepatic synthesised cholesterol is incorporated into VLDL
E. thyroid hormones decrease the plasma cholesterol level
Answer: B.about 20% is in the plasma, with the remainder intracellular
171. How many ATP molecules are produced from one glucose molecule metabolised aerobically via the Embden-Meyerhof pathway and citric acid cycle?
A. 32
B. 34
C. 36
D. 38
E. 40
Answer: D.38
172. Which lipoprotein contains the GREATEST proportion of triglyceride?
A. VLDL
B. IDL
C. chylomicrons
D. LDL
E. HDL
Answer: C.chylomicrons
173. Basal metabolic rate is GREATER in all of the following circumstances EXCEPT:
A. children compared with adults
B. Caucasians compared with Chinese and Indians
C. females compared with males
D. anxiety compared with depression
E. feeding compared with starvation
Answer: C.females compared with males
174. Which lipoprotein contains the GREATEST proportion of cholesterol and cholesterolesters?
A. VLDL
B. IDL
C. chylomicrons
D. LDL
E. HDL
Answer: D.LDL
175. What is the basal metabolic rate of an average sized man per day?
A. 1000 Kcal
B. 2000 Kcal
C. 3000 Kcal
D. 4000 Kcal
E. 5000 Kcal
Answer: B.2000 Kcal
176. Which lipoprotein contains the GREATEST proportion of protein?
A. VLDL
B. IDL
C. chylomicrons
D. LDL
E. HDL
Answer: E.HDL
177. What is the most important factor affecting metabolic rate?
A. muscular exertion
B. recent ingestion of food
C. high or low environmental temperature
D. height, weight and surface area
E. sex
Answer: A.muscular exertion
178. Which of the following are NON ESSENTIAL amino acids?
A. valine
B. leucine
C. isoleucine
D. cysteine
E. methionine
Answer: D.cysteine
179. Regarding plasma protein, all of the following are correct EXCEPT:
A. albumin, globulin and fibrinogen constitute the major plasma proteins in the plasma
B. the fibrinogen polymerises into long fibrin threads during blood coagulation
C. the principal function of albumin is to provide colloid osmotic pressure in the plasma
D. the majority of plasma proteins are formed in the lymphoid tissue
E. rapid loss of plasma proteins may occur during severe burns
Answer: D.the majority of plasma proteins are formed in the lymphoid tissue
180. Factors that predisposes to atherosclerosis includes all of the following EXCEPT:
A. diabetes
B. hypothyroidism
C. smoking
D. male sex
E. female sex hormone
Answer: E.female sex hormone
181. Lipoproteins:
A. chylomicrons are themselves very large lipoproteins composed of cholesterol, phospholipids, triglycerides and proteins
B. VLDL contains a higher concentration of triglycerides and a moderate concentration of cholesterol and proteins
C. HDL contains a very higher concentration of cholesterol and a moderate concentration of phospholipids and triglycerides
D. the majority of the lipoproteins are synthesised in the liver
E. the primary function of the lipoproteins are to transport lipids in the blood from liver to adipose tissue
Answer: C.HDL contains a very higher concentration of cholesterol and a moderate concentration of phospholipids and triglycerides
182. Glycogenolysis:
A. is a process of formation of glycogen in the cell
B. is a process of breakdown of glycogen to reform glucose
C. is the conversion of glucose into fructose
D. is the process of breakdown of galactose
E. is the formation of galactose from fructose
Answer: B.is a process of breakdown of glycogen to reform glucose
183. Regarding ATP:
A. ATP is a combination of adenine, ribose and 3 phosphate radicals
B. ATP are present everywhere in the cytoplasm and nucleoplasm
C. ATP is otherwise called the energy currency of the body
D. ATP becomes GTP after the loss of one phosphate radical
E. ATP is a labile chemical compound that is present in all cells
Answer: D.ATP becomes GTP after the loss of one phosphate radical
184. In the body, metabolism of 10gm protein would produce approximately:
A. 1 Kcal
B. 41 Kcal
C. 410 Kcal
D. 4100 Kcal
E. 41 Cal
Answer: B.41 Kcal
185. Regarding 1,25 dihydroxycholecalciferol (calcitriol):
A. it is formed by the action of sunlight on pre vitamin D3
B. it exerts its action via stimulation of adenylcyclase
C. it decreases calcium reabsorption from kidneys
D. its formation is increased with elevated plasma Ca++ levels
E. it causes increased formation of calbindin-D proteins
Answer: E.it causes increased formation of calbindin-D proteins
186. The following are active components in the peripheral circulation, EXCEPT:
A. T3
B. T4
C. DIT
D. RT3
E. all of the above
Answer: C.DIT
187. Calitriol (1,25-dihydroxycholecalciferol)
A. inhibits Ca++ absorption from the gut
B. is formed in the proximal renal tubules from a less active precursor
C. levels rise in response to increase serum PO4 levels
D. inhibits osteoclasts function
E. inhibits osteoblasts function
Answer: B.is formed in the proximal renal tubules from a less active precursor
188. Stimuli that increase renin secretion include all EXCEPT:
A. hypotension
B. Na+ depletion
C. cardiac failure
D. lying down
E. diuretics
Answer: D.lying down
189. Regarding parathyroid hormone, which is NOT true?
A. it decreases plasma phosphate
B. it is secreted by chief cells of he parathyroid glands
C. it is cleared by Kupffer cells of the liver
D. its secretion is regulated by the level of bound Ca++ in plasma
E. it increases bone reabsorption
Answer: D.its secretion is regulated by the level of bound Ca++ in plasma
190. Which of the following reduce insulin secretion?
A. acetylcholine
B. GIP
C. glucagon
D. adrenaline
E. β ketoacids
Answer: D.adrenaline
191. With regard to the effect of thyroid hormone on the cardiovascular system, which of the following are TRUE?
A. level of noradrenaline are increased
B. β adrenergic receptor affinity is decreased in heart muscle
C. circulating adrenaline levels are decreased
D. thyroid hormone levels alter the ratio of cardiac myosin isoform types
E. none of the above
Answer: D.thyroid hormone levels alter the ratio of cardiac myosin isoform types
192. Stimuli that increase aldosterone secretion and do not effect glucocorticoid secretionincludes all EXCEPT:
A. low Na+ intake
B. high K+ intake
C. standing
D. secondary hyperaldosteronism
E. haemorrhage
Answer: E.haemorrhage
193. Signs and effects of hyperparathyroidism include all EXCEPT:
A. renal stones
B. demineralization of bones
C. Chvostek’s and Trousseau’s signs
D. hypercalcaemia
E. hypophosphataemia
Answer: C.Chvostek’s and Trousseau’s signs
194. Glucagon levels are increased by:
A. secretin
B. somatostatin
C. cholecystokinin
D. free fatty acids
E. ketones
Answer: C.cholecystokinin
195. Insulin release:
A. is inhibited by raised cyclic AMP in pancreatic β cells
B. is not stimulated by blood glucose levels below 6mmol/l
C. is increased by β adrenergic stimulators
D. is inhibited by phosphor diesterase inhibitors
E. is increased by somatostatin
Answer: C.is increased by β adrenergic stimulators
196. Trace elements believed essential to life include all EXCEPT:
A. arsenic
B. cyanide
C. cobalt
D. silicon
E. nickel
Answer: B.cyanide
197. Mono-iodotyrosin (MIT) and diiodotyrosin (DIT) molecules:
A. are deiodinated before joining to form T3 and T4
B. are secreted into plasma alongside T3 and T4
C. are the inactive metabolites of T3 and T4
D. are cleaved from thyroglobulin by proteases in lysosomes
E. are usually excreted in the urine
Answer: D.are cleaved from thyroglobulin by proteases in lysosomes
198. Calcitonin secretion is stimulated by the following EXCEPT:
A. gastrin
B. somatostatin
C. oestrogen
D. cholecystokinin
E. glucagon
Answer: B.somatostatin
199. With regard to gastric acid secretion, all the following are true EXCEPT:
A. acetylcholine stimulates secretion
B. both G protein and direct calcium channels are involved
C. an H+ – K+ antiport transports H+ into the gastric lumen
D. parietal cells have high levels of carbonic anhydrase
E. acid secretion is maintained at constant levels by local feedback mechanisms
Answer: E.acid secretion is maintained at constant levels by local feedback mechanisms
200. Tissues in which insulin does NOT facilitate glucose uptake?
A. red blood cells
B. skeletal muscle
C. cardiac muscle
D. smooth muscle
E. aorta
Answer: A.red blood cells
201. Regarding the “iodide pump” in thyroid cells, which is NOT true?
A. it is stimulated by TSH
B. it depends on Na+ / K+ ATPase activity
C. it pumps iodide into the colloid, after entering the cell down an electrical gradient
D. it pumps iodide against an electrical gradient
E. its activity can be measured with trace doses of radioactive iodine
Answer: C.it pumps iodide into the colloid, after entering the cell down an electrical gradient
202. Which of the following enzymes are missing in the zona glomerulosa?
A. 17 α hydroxylase
B. 11 β hydroxylase
C. 21 β hydroxylase
D. cholesterol desmolase
E. 3 β hydroxysteroid
Answer: A.17 α hydroxylase
203. The effects of hyperthyroidism on the cardiovascular system include all of thefollowing EXCEPT:
A. increased expression of α MHC isoforms in cardiac muscle
B. increased catecholamine plasma levels
C. increased number of β receptors
D. increased affinity of β receptors
E. vasodilation of peripheral vessels
Answer: B.increased catecholamine plasma levels
204. Regarding the control of thyroid secretion:
A. free T3 and T4 exert feedback control on anterior pituitary
B. free T3 and T4 exert feedback control on hypothalamus
C. free T3 and T4 exert feedback control on anterior pituitary and hypothalamus
D. free T3 and T4 do not affect day to day control of their secretion
E. the basal metabolic rate is the most important determinant of thyroid secretion
Answer: C.free T3 and T4 exert feedback control on anterior pituitary and hypothalamus
205. The following are true of chylomicrons EXCEPT:
A. they are large lipoprotein complexes
B. they are part of the exogenous lipid transport system
C. they enter the circulation via the lymphatic ducts
D. they are cleared from the circulation by lipoprotein lipase on the surface of hepatocytes
E. chylomicron remnants are bound to LDL R and endocytosed
Answer: D.they are cleared from the circulation by lipoprotein lipase on the surface of hepatocytes
206. All of the following are true regarding chylomicrons EXCEPT:
A. they contain triglycerides, cholesterol and phospholipids
B. they are formed in the intestinal mucosa
C. they are cleared from the circulation by lipoprotein lipase
D. they are transported to the liver by the portal circulation
E. large numbers after a meal give the plasma a milky appearance
Answer: D.they are transported to the liver by the portal circulation
207. The tissue or organ with the greatest potential for increasing the metabolic rate of thebody is:
A. liver
B. skin
C. adipose tissue
D. skeletal muscle
E. digestive system
Answer: D.skeletal muscle
208. Triglycerides are transported to cells via:
A. chylomicron remnants
B. HDL
C. LDL
D. VLDL
E. none of the above
Answer: D.VLDL
209. Regarding vitamin B12
A. it is a fat soluble vitamin
B. its absorption is inhibited by trypsin
C. it is mainly carried in plasma by attachment to albumin
D. it undergoes enterohepatic circulation
E. none of the above are true
Answer: D.it undergoes enterohepatic circulation
210. Regarding HDL:
A. HDL transports ingested cholesterol from the intestine
B. HDL transports triglycerides from peripheral tissues
C. HDL receptors on macrophages are called scavenger receptors
D. elevated HDL levels are associated with increased risk of atherosclerosis
E. none of the above are correct
Answer: C.HDL receptors on macrophages are called scavenger receptors
211. Regarding free fatty acids in plasma, which of the following is NOT true?
A. they account for less than 10% of total fatty acids in plasma
B. they are complexed with a protein carrier
C. they can be metabolised to CO2 and water in skeletal and cardiac muscle
D. their level in plasma decreases as plasma adrenaline increases
E. they are converted to energy by the citric acid cycle
Answer: D.their level in plasma decreases as plasma adrenaline increases
212. Ubiquitin is:
A. an essential amino acid
B. a polypeptide that tags proteins for degradation
C. a cell membrane glycoprotein
D. a precursor or uric acid
E. none of the above
Answer: B.a polypeptide that tags proteins for degradation
213. In a fasting adult at rest:
A. skeletal muscle metabolises mainly glucose
B. the brain accounts for approximately 40% of glucose utilised
C. blood glucose concentrations are higher in women than in men
D. blood glucose levels are maintained initially by hepatic glycogenolysis
E. ketones are absent from plasma
Answer: D.blood glucose levels are maintained initially by hepatic glycogenolysis
214. Uric acid handling by the kidneys involves:
A. filtration only
B. secretion by tubules only
C. filtration and secretion
D. filtration and reabsorption
E. filtration, reabsorption and secretion
Answer: E.filtration, reabsorption and secretion
215. The following vitamin is fat soluble:
A. niacin
B. B6
C. K
D. pantothenic acid
E. biotin
Answer: C.K
216. With regard to the metabolism of carbohydrates:
A. in the absence of liver glycogen stores, glycogen administration does not cause hyperglycaemia
B. glucocorticoids have a minor effect on gluconeogenesis
C. growth hormone causes increased use of glucose for energy
D. glucose is absorbed by most cells by active sodium glucose co-transport
E. during starvation, stores last for less than 24 hours
Answer: E.during starvation, stores last for less than 24 hours
217. With regard to lipid metabolism:
A. only HDL is formed in the liver
B. fatty acids in the plasma form 1:1 complexes with albumin
C. plasma cholesterol levels rise considerably with an increase in daily ingestion
D. free fatty acids are metabolised in preference to glucose in a non-exercising individual
E. utilisation of fatty acids is stimulated by glucocorticoids
Answer: E.utilisation of fatty acids is stimulated by glucocorticoids
218. With regard to carbohydrate metabolism:
A. the normal fasting glucose is from 3.9 to 11.0mmol/L
B. glucose is phosphylated in cells to glucose-6-phosphate by phosphoenol-pyrunate carboxykinase
C. glycogen, the storage form of glucose, is only in the liver and skeletal muscle
D. glucose can be converted to fats through acetyl CoA which is irreversible
E. none of the above
Answer: D.glucose can be converted to fats through acetyl CoA which is irreversible
219. Which statement regarding glucagon is INCORRECT?
A. it is used as an antidote in symptomatic beta blocker overdosage
B. it is synthesised in the A cells of the pancreatic islets and in small intestinal mucosal cells
C. its major site of metabolism is in the plasma
D. it is synthesised in common with glicentin
E. the exogenous glucagon is associated with nausea and vomiting
Answer: C.its major site of metabolism is in the plasma
220. Which of the following is NOT an action of somatostatin?
A. it inhibits glucagon secretion
B. it is a synaptic transmitter in the retina
C. it inhibits insulin secretion
D. it increases contraction of the gallbladder
E. it inhibits pancreatic polypeptide secretion
Answer: D.it increases contraction of the gallbladder
221. Glucagon increases the secretion of all of the following EXCEPT:
A. catecholamines from a phaeochromocytoma
B. atrial natriuretic peptide
C. growth hormone
D. insulin
E. calcitonin from a medullary carcinoma of the thyroid
Answer: B.atrial natriuretic peptide
222. Regarding the actions of glucagon, which of the following is INCORRECT?
A. it increases blood lactate level
B. it activates hormone-sensitive lipase
C. it has a positive inotropic effect on myocardium
D. large amounts cause intestinal relaxation
E. it decreases renal tubular sodium reabsorption
Answer: A.it increases blood lactate level
223. Which of the following does NOT increase pancreatic polypeptide secretion?
A. protein ingestion
B. fasting
C. exercise
D. acute hypoglycaemia
E. intravenous glucose
Answer: E.intravenous glucose
224. Which iodinated compound is present in GREATEST amounts in the adult thyroidgland?
A. T4
B. DIT
C. MIT
D. T3
E. RT3
Answer: A.T4
225. Regarding the action of glucagon on the liver, which of the following is INCORRECT?
A. it causes glycogenolysis via activation of adenylate cyclase
B. it decreases metabolism of glucose-6-phosphate
C. it causes glycogenolysis via activation of phospholipase C
D. it increases gluconeogenesis from available amino acids
E. it decreases ketone body formation
Answer: E.it decreases ketone body formation
226. Regarding the synthesis of thyroid hormones, which statement is INCORRECT?
A. iodine undergoes rapid oxidation following entry to thyroid cells
B. the “iodine pump” is the major source of iodine for hormone synthesis
C. TSH increases iodine uptake by the thyroid gland
D. thiocyanate and ouabain decrease iodine uptake by the thyroid gland
E. it involves iodination of thyrosine residues in thyroglobulin
Answer: B.the “iodine pump” is the major source of iodine for hormone synthesis
227. Which of the following does NOT inhibit secretion of glucagon?
A. ketones
B. α adrenoceptor agonists
C. secretin
D. amino acids
E. somatostatin
Answer: D.amino acids
228. Which plasma protein has the greatest thyroxine binding capacity?
A. α 1-acid glycoprotein
B. thyroxine-binding pre-albumin
C. albumin
D. thyroxine-binding globulin
E. orosomucoid
Answer: C.albumin
229. Which of the following does NOT increase secretion of glucagon?
A. diabetes mellitus
B. β adrenoceptor agonists
C. GABA
D. starvation
E. exercise
Answer: C.GABA
230. Which plasma protein has the greatest thyroxine-binding affinity?
A. α 1-acid glycoprotein
B. thyroxine-binding pre-albumin
C. albumin
D. thyroxine-binding globulin
E. orosomucoid
Answer: D.thyroxine-binding globulin
231. Regarding insulin, which statement is INCORRECT?
A. it consists of two polypeptide chains linked by two disulphide bridges
B. the majority of exogenous insulin is metabolised by the liver
C. it is not the only molecule responsible for insulin-like activity in the blood
D. it increases intracellular potassium concentration
E. exercise increases the affinity of its receptors for insulin
Answer: B.the majority of exogenous insulin is metabolised by the liver
232. Which iodinated compound is present in the SMALLEST amounts in the adult thyroidgland?
A. T4
B. DIT
C. MIT
D. T3
E. RT3
Answer: E.RT3
233. Which of the following hormones does NOT increase the hepatic output of glucose?
A. growth hormone
B. adrenaline
C. glucagon
D. noradrenaline
E. cortisol
Answer: A.growth hormone
234. Which thyroid hormone has the longest plasma half-life?
A. T4
B. DIT
C. MIT
D. T3
E. RT3
Answer: A.T4
235. Regarding the action of insulin on adipose tissue, which of the following isINCORRECT?
A. it induces lipoprotein lipase which actively hydrolyses triglyceride from circulating lipoproteins
B. it reduces circulating free fatty acids
C. it promotes triglyceride storage in adipocytes
D. it directly inhibits intracellular lipase
E. its effects appear to involve phosphorylation of lipases
Answer: E.its effects appear to involve phosphorylation of lipases
236. Which of the following tissues possess FEW thyroid hormone receptors?
A. liver
B. testis
C. kidney
D. heart
E. skeletal muscle
Answer: B.testis
237. Which glucose transporter is responsible for insulin-mediated glucose uptake instriated muscle and adipose tissue?
A. glut 1
B. glut 2
C. glut 3
D. glut 4
E. glut 5
Answer: D.glut 4
238. Where are the receptors located by which thyroid hormones mediate most of theireffects?
A. cell membrane
B. outer mitochondrial membrane
C. nuclear chromatin
D. inner mitochondrial membrane
E. cytoplasm
Answer: C.nuclear chromatin
239. Regarding the action of insulin in skeletal muscle, which of the following isINCORRECT?
A. it decreases protein catabolism
B. it induces glucogen synthase
C. it decreases ketone uptake
D. it increases amino acid uptake
E. it decreases the release of gluconeogenic amino acids
Answer: C.it decreases ketone uptake
240. Which thyroid hormone possesses the GREATEST biological activity?
A. T4
B. DIT
C. MIT
D. T3
E. RT3
Answer: D.T3
241. Which glucose transporter is responsible for the facilitated diffusion of glucose intopancreatic B cells?
A. glut 1
B. glut 2
C. glut 3
D. glut 4
E. glut 5
Answer: B.glut 2
242. Regarding the effects of thyroid hormones, which of the following does NOT occur?
A. it increases metabolic rate
B. it directly stimulates sodium-potassium ATPase
C. it increases protein and fat catabolism
D. it increases body temperature
E. it increases cerebral oxygen consumption
Answer: E.it increases cerebral oxygen consumption
243. Regarding the action of insulin on the liver, which of the following is INCORRECT?
A. it increases gluconeogenesis
B. it decreases glycogenolysis
C. it increases synthesis of triglyceride and VLDL
D. it decreases cyclic AMP
E. it increases phosphate uptake
Answer: A.it increases gluconeogenesis
244. Which statement regarding the thyroid gland and its hormones is INCORRECT?
A. thyroid hyperactivity is associated with an increase in plasma catecholamines
B. iodide trapping by thyroid cells is an active process
C. thyroid hormones enter cells by diffusion across the cell membrane
D. thyroid hormones cause an increase in 2,3 – DPG
E. thyroid hormones increase growth hormone secretion
Answer: A.thyroid hyperactivity is associated with an increase in plasma catecholamines
245. Regarding the secretion of insulin, which statement is INCORRECT?
A. insulin is not required for glucose to enter pancreatic B cells
B. it involves closure of ATP-sensitive potassium channels
C. it is a biphasic process involving two pools of insulin
D. it involves opening of voltage-sensitive calcium channels
E. glucose enters pancreatic B cells by combining with glut 4
Answer: E.glucose enters pancreatic B cells by combining with glut 4
246. Which of the following do NOT increase TSH secretion?
A. TRH
B. glucocorticoids
C. infants exposed to cold temperature
D. acute psychosis
E. night time
Answer: B.glucocorticoids
247. Which of the following does NOT inhibit insulin secretion?
A. somatostatin
B. atropine
C. propranolol
D. gastrin
E. phenytoin
Answer: D.gastrin
248. Which of the following does NOT increase intestinal calcium absorption?
A. hypocalcaemia
B. parathyroid hormone (PTH)
C. glucocorticoids
D. hypervitaminosis D
E. protein in diet
Answer: C.glucocorticoids
249. Which of the following does NOT stimulate insulin secretion?
A. acetoacetate
B. glucagon
C. hypokalaemia
D. acetylcholine
E. theophylline
Answer: C.hypokalaemia
250. Which of the following does NOT decrease intestinal calcium absorption?
A. hypercalcaemia
B. decreased PTH
C. hypovitaminosis D
D. growth hormone
E. phytic acid and oxalate in intestine
Answer: D.growth hormone
251. Regarding the insulin receptor, which statement is INCORRECT?
A. it is present even in cells which do not increase their glucose intake in response to insulin
B. insulin binds to the β subunit on the outer surface of the cell membrane
C. it is a tetramer of two α and two β subunits
D. the binding of insulin decreases the activity of tyrosine kinase on the intracellular end of the receptor
E. the complex of insulin and receptor become internalised by the cell
Answer: B.insulin binds to the β subunit on the outer surface of the cell membrane
252. Which of the following does NOT increase plasma calcium?
A. parathyroid hormone
B. vitamin D
C. growth hormone
D. thyroxine
E. calcitonin
Answer: E.calcitonin
253. Which of the following is NOT associated with an increase in erythropoietinsecretion?
A. aminophylline
B. renal cell carcinoma
C. cobalt salts
D. thyroxine
E. adenosine
Answer: A.aminophylline
254. Which of the following does NOT increase parathyroid hormone secretion?
A. high plasma magnesium
B. low plasma calcium
C. high plasma phosphate
D. β-adrenergic discharge
E. cyclic AMP
Answer: A.high plasma magnesium
255. Regarding erythropoietin, which statement is INCORRECT?
A. its secretion increases within minutes to hours in response to hypoxia
B. it causes pro-erythroblasts to mature more rapidly into erythrocytes
C. the spleen and salivary glands secrete, but don’t synthesise it
D. it inhibits apoptosis in erythroid stem cells
E. the adult liver is able to synthesise enough for normal erythropoiesis in the absence of both kidneys
Answer: E.the adult liver is able to synthesise enough for normal erythropoiesis in the absence of both kidneys
256. Which statement regarding parathyroid hormone (PTH) is INCORRECT?
A. it is continuously secreted by the parathyroid glands
B. it is synthesised and secreted by the oxyntic cells
C. it is rapidly cleaved in the Kupffer cells of the liver
D. it increases osteoclasts activity in bone
E. it increases formation of 1,25-dihydroxycholecalciferol
Answer: B.it is synthesised and secreted by the oxyntic cells
257. Regarding endothelins, which statement is INCORRECT?
A. they can cause dose-dependent vasoconstriction in most vascular beds
B. they activate phospholipase C
C. they are structurally similar to vasoactive intestinal contractor
D. they have negative inotropic effect
E. there are low concentrations present in blood
Answer: D.they have negative inotropic effect
258. Which statement regarding calcitonin is INCORRECT?
A. it is secreted by parafollicular cells of the thyroid gland
B. it inhibits osteoclastic bone resorption
C. total thyroidectomy is usually associated with hypercalcaemia
D. it decreases renal tubular calcium and phosphate reabsorption
E. it is only secreted when plasma calcium concentration exceeds 9.5mg/100ml
Answer: C.total thyroidectomy is usually associated with hypercalcaemia
259. Regarding atrial natriuretic peptide, which statement is INCORRECT?
A. cardiac innervation is not required for secretion to occur
B. its action is terminated by receptor-mediated endocytosis
C. its filtration fraction is decreased
D. it is secreted by heart, lung and brain
E. glucocorticoids increase its secretion
Answer: C.its filtration fraction is decreased
260. Regarding the role of vitamin D in calcium metabolism, which of the following isINCORRECT?
A. it increases renal tubular calcium and phosphate reabsorption
B. it causes an increase in synthesis of calcium-binding protein
C. it increases bone resorption
D. it decreases bone formation
E. it increases intestinal calcium and phosphate absorption
Answer: D.it decreases bone formation
261. Atrial natriuretic peptide decreases formation of all of the following EXCEPT:
A. aldosterone
B. cyclic GMP
C. renin
D. vasopressin
E. angiotensin III
Answer: B.cyclic GMP
262. Which of the following does NOT increase aldosterone secretion?
A. constriction of the IVC in the thorax
B. ACTH
C. surgery
D. hyperkalaemia
E. lying supine from the standing position
Answer: E.lying supine from the standing position
263. Which of the following does NOT increase secretion of atrial natriuretic peptide?
A. β-adrenoceptor agonists
B. immersion in water up to the neck
C. exercise
D. endothelin
E. changing from erect position to supine
Answer: A.β-adrenoceptor agonists
264. Regarding aldosterone, which statement is INCORRECT?
A. it responds to changes in plasma sodium more strongly than changes in plasma potassium
B. it is only synthesised in the zona glomerulosa of the adrenal cortex
C. its main action is to increase the synthesis of sodium-potassium pumps
D. angiotensins II and III have about equal mineralocorticoid stimulating activity
E. it acts via a cytoplasmic receptor that has equal affinity for cortisol
Answer: A.it responds to changes in plasma sodium more strongly than changes in plasma potassium
265. A 15-year-old girl suffers from a malabsorption syndrome characterised by the malabsorption of fat. In which vitamin is she MOST likely to be deficient?
A. niacin
B. B6
C. K
D. pantothenic acid
E. biotin
Answer: C.K
266. Thyroxine (T4):
A. secretion is regulated by positive feedback at the hypothalamus
B. is transported principally by albumin in the blood
C. causes increased LDLD in plasma
D. is physiologically more active than T3
E. increases β receptors in the cardiovascular system
Answer: E.increases β receptors in the cardiovascular system
267. Regarding insulin:
A. it increases amino acid uptake
B. its absorption is not affected by the site of injection
C. it causes reduced K+ uptake by cells
D. it increases protein catabolism
E. it is secreted by the α cells in the islets of Langerhan
Answer: A.it increases amino acid uptake
268. The content of chylomicrons includes:
A. aproprotein E and aproprotein A
B. cholesterol 30%, protein 20%, triglyceride 50%
C. lethicin 10%, cholesterol 25%, triglyceride 65%
D. protein 2%, cholesterol 5%, triglyceride 90%
E. the enzyme protein phospholipase
Answer: D.protein 2%, cholesterol 5%, triglyceride 90%
269. Regarding calcium metabolism:
A. the adult human body contains 15% of its body mass as calcium
B. calcium is passively absorbed from the intestinal brush border
C. oestrogen inhibits osteoclasts
D. TNF inhibits osteoclasts
E. corticosteroids stimulate osteoblasts
Answer: C.oestrogen inhibits osteoclasts
chapter:
General Physiology
270. Regarding cellular components:
A. peroxisomes are larger than lysosomes
B. pH of lysosomes is higher than the rest of the cytoplasm
C. microfilaments are hollow
D. myosin 1 molecules are characteristically found in muscle cells
E. microfilaments are made up of actin
Answer: E.microfilaments are made up of actin
271. Na+ -K+ -ATPase is an example of a/an:
A. symport
B. uniport
C. biport
D. antiport
E. airport
Answer: D.antiport
272. Which decreases Na+ -K+ -ATPase pump activity?
A. thyroid hormones
B. dopamine
C. G-actin
D. intracellular sodium
E. insulin
Answer: B.dopamine
273. Given that a person weighs 60kg and their haematocrit is 40%, their totalblood volume is:
A. 6L
B. 5L
C. 4L
D. 3L
E. cannot be calculated with the given information
Answer: B.5L
274. What percentage of body weight is plasma?
A. 2%
B. 5%
C. 8%
D. 15%
E. 20%
Answer: B.5%
275. ECF volume can be estimated using:
A. inulin
B. D2O
C. Evan’s blue
D. radioactive chromium
E. iron isotopes
Answer: A.inulin
276. The number of molecules in a mole is:
A. 1 X 1026
B. 6 X 1026
C. 4 X 1026
D. 1 X 1023
E. 6 X 1023
Answer: E.6 X 1023
277. The molecular mass of a substance is expressed in:
A. moles
B. Daltons
C. equivalents
D. osmoles
E. grams
Answer: B.Daltons
278. Regarding mitochondria:
A. genome inheritance is strictly maternal
B. the citric acid cycle occurs at the outer membrane
C. the space between the two membranes is called the matrix
D. the mutation rate for mitochondrial DNA is less than for nuclear DNA
E. involutions of the outer membrane are called cristae
Answer: A.genome inheritance is strictly maternal
279. Which volume of distribution is evaluated with which substance?
A. plasma – D2O
B. RBC volume – 51Cr
C. ECF – Evans Blue
D. Interstitial fluid – Inulin
E. ICF – mannitol
Answer: B.RBC volume – 51Cr
280. Which is correct?
A. blood volume is 8% total body weight
B. 2/3 total body weight is ECF
C. 75% of ECF is blood plasma
D. water content of lean tissue is 25%
E. total body water increases with increasing age
Answer: A.blood volume is 8% total body weight
281. For mitochondria, which is TRUE?
A. NADH-DH, 5DH, bc, cox synthesise ATP
B. the matrix is between the inner and outer mitochondrial DNA
C. mitochondrial DNA is not transmitted paternally
D. 99% of mitochondrial proteins are encoded by mitochondrial DNA
E. ATP synthetase is powered by an electron gradient
Answer: C.mitochondrial DNA is not transmitted paternally
282. Which is TRUE?
A. the cytoskeleton is composed of hydroxyapatites
B. the mitotic spindle is composed of actin microtubules
C. myosin is the most abundant protein in cells
D. colchicine stabilises microtubules preventing organelle movement
E. actin-myosin interaction allows cells to move
Answer: E.actin-myosin interaction allows cells to move
283. For the genome, which is TRUE?
A. the human genome encodes 3 X 109 genes
B. adenine binds to cytosine and guanine to thymine
C. uracil replaces thymine in RNA
D. 3% of DNA are introns
E. haploid DNA in germ cells is single stranded
Answer: C.uracil replaces thymine in RNA
284. For transmembrane movement, which is TRUE?
A. exocytosis requires Ca2+ and energy
B. Na+ -K+ -ATPase is an example of facilitated diffusion
C. amiloride activates epithelial Na+ channels
D. clathrin is essential for vesicle exocytosis
E. water can only enter cells via water channels
Answer: A.exocytosis requires Ca2+ and energy
285. For the Erlanger and Gasser classification, which is TRUE?
A. Sunday morning syndrome mainly affects C fibres
B. local anaesthetics primarily affect A fibres
C. preganglionic autonomic fibres are type B
D. C fibres have the largest diameter
E. B fibres are the least susceptible to hypoxia
Answer: C.preganglionic autonomic fibres are type B
286. For the glial cells, which is TRUE?
A. one schwann cell can myelinate up to 40 neurons
B. oligodenotocytes are the scavenger cells of the CNS
C. microglia are the scavenger cells of the PNS
D. there are up to three glial cells per neuron in the nervous system
E. protoplasmic astrocytesase found in grey matter
Answer: E.protoplasmic astrocytesase found in grey matter
287. For cardiac muscle, which is FALSE?
A. HERG really is the acronym for human ether-a-go-go related gene
B. intercolated discs are calcified structures within cardiac muscle cells
C. resting membrane potential is -90mV
D. cardiac muscle requires continuous supply of O2 to function
E. cardiac muscle action potential time decreases with increasing heart rate
Answer: B.intercolated discs are calcified structures within cardiac muscle cells
288. For neurotransmitters, which is TRUE?
A. acetylcholine is synthesised by true cholinesterase
B. atropine blocks muscarinic cholinergic receptors
C. catecholamines are formed from VMA (vanillylmandelic acid)
D. adrenaline has a higher affinity for α rather than β adrenergic receptors
E. dopamine is formed by COMT from tryptophan
Answer: B.atropine blocks muscarinic cholinergic receptors
289. Regarding body water, which is FALSE?
A. 1/3 total body weight is extra and 2/3 intra cellular
B. 60% of body weight is water
C. plasma is 8% and total blood 10%, of body weight
D. of extracellular fluid, 25% is vascular, 75% extravascular
E. interstitial fluid is 15% of body weight
Answer: C.plasma is 8% and total blood 10%, of body weight
290. Chemical composition, which is TRUE?
A. pH is the negative natural logarithm of [H+]
B. pH 5 to pH 6 involves tenfold increase in [H+]
C. pH remains 7.4 +/- 0.05 in ECF, stabilised by buffer
D. H2O and CO2 H2CO3 H+ and HCO3-, adding H+ shifts the equilibrium to the right, while adding ??? shifts it to the left
E. the Donnan effect does not contribute significantly to the balance of electrolyte between intra and extra vascular compartment
Answer: C.pH remains 7.4 +/- 0.05 in ECF, stabilised by buffer
291. Nerve fibres, which is FALSE?
A. 70% of energy requirement of nerves is used in maintaining polarity across the recytlemina by action of Na-K ATPase
B. metabolic rate of nerves doubles in max action
C. “C” type fibres are non-myelinated and include some of the sympathetic preganglionic fibres
D. “A” and “B” fibres are all myelinated
E. effects of local anaesthetic are maximal in “C” fibres
Answer: C.“C” type fibres are non-myelinated and include some of the sympathetic preganglionic fibres
292. Regarding skeletal muscle, which is FALSE?
A. metabolic rate of muscle may increase 100 times in maximal activity
B. muscle cells can be excited chemically, mechanically and electrically, to produce action potentials in the cell membrane
C. actin is a myosin-binding protein which is a molecular motor, converting ATP energy to monomers
D. mitochondria are packed in between myofibrils
E. T tubules occur over the junction of I and A bands
Answer: C.actin is a myosin-binding protein which is a molecular motor, converting ATP energy to monomers
293. More on muscles; which is TRUE?
A. skeletal muscle cells act as syncytram, though intercellular communications
B. some skeletal muscles are not subject to voluntary control
C. smooth muscle contains regularly discharging pacemaker
D. a variant of smooth muscle is found in the eye, which resembles skeletal muscle
E. cardiac muscle does not contain regular striation
Answer: D.a variant of smooth muscle is found in the eye, which resembles skeletal muscle
294. More on muscles; which is FALSE?
A. T tubules are extensions of extracellular space
B. “cystems’ of SR are in contact with T-tubules
C. myosin molecules combine to form thick filaments while actin, tropomyosin, and the troponins the t…..
D. an individual muscle cell is a myofibril, containing myofilaments
E. the sarcolemnia transmits action potentials
Answer: D.an individual muscle cell is a myofibril, containing myofilaments
295. In muscle construction, which is TRUE?
A. only contraction is energy requiring, not relaxing
B. sequestering of Ca2+ causes separation of actin-myosin bands and muscle relaxation
C. ATPase clefts are on the tips of the myosin beads
D. ryanodine receptors are voltage gated Ca2+ chains
E. Troponin T inhibits the interaction of actin and myosin
Answer: B.sequestering of Ca2+ causes separation of actin-myosin bands and muscle relaxation
296. Action potentials:
A. travel along neurons at a set velocity
B. are only seen in neurons
C. are generated initially by action of K+ voltage gated channels
D. result from variation in Na+ and K+ membrane permeability
E. are unidirectional impulses
Answer: D.result from variation in Na+ and K+ membrane permeability
297. The Na+ K+ ATPase pump:
A. utilises ATP to pump out 2 Na+ ions for every 3 K+ ions
B. activity is altered by insulin, aldosterone and thyroid hormones
C. is only found in muscle and nervous tissue
D. is made of α, β, and δ subunits
E. ATP binds to the α subunit causing a protein configuration change
Answer: B.activity is altered by insulin, aldosterone and thyroid hormones
298. Which is TRUE?
A. active transport is the major method for transport of glucose into cells
B. facilitated diffusion utilises ATP to transport ions against their chemical or electrical gradients
C. an example of an active transporter is the K+ H+ ATPase found in the gastric mucosa
D. the H+ K+ ATPase is an example of an electrogenic pump
E. none of the above
Answer: C.an example of an active transporter is the K+ H+ ATPase found in the gastric mucosa
299. The golgi apparatus, which is TRUE?
A. is found only in secretory cells
B. vesicles containing newly synthesised proteins bind to trans side of the apparatus
C. constitutive pathway of cell secretion is responsible for further processing and storage of proteins
D. is responsible for glycorylation of proteins
E. none of the above
Answer: E.none of the above
300. With respect to protein synthesis:
A. each amino acid found in human protein has its own individual single transfer RNA
B. pre mRNA processing occurs in the cytoplasm prior to binding to ribosomes on the endoplasmic retic???
C. each gene has regulatory, promoter, coding and non coding regions which are all transcribed into pre mRNA
D. introns no recognised physiological function
E. the promoter site of a gene is the site where RNA polymerase binds
Answer: E.the promoter site of a gene is the site where RNA polymerase binds
301. Which is TRUE?
A. polymerase chain reaction may be used to repair damaged DNA
B. restriction fragment length polymorphism detects differences in DNA sequences between different individuals
C. protein encoding genes make up only 15% of the human genome
D. the only difference between DNA and RNA is the substitution of uracil for thymine
E. the haploid human genome is made up of 3 X 106 base pairs
Answer: B.restriction fragment length polymorphism detects differences in DNA sequences between different individuals
302. Action potentials in skeletal muscle:
A. travel along muscle fibres at varying rates
B. have larger retratory periods compared to nerves
C. causes uptake of Ca++ into sacroplasmic reticulum
D. results in sustained contraction of muscle fibres
E. the haploid human genome is made up of 3 X 106 base pairs
Answer: B.have larger retratory periods compared to nerves
303. Regarding membrane potential:
A. it is only found in nervous tissue
B. Na+/K+ pump does not contribute to the membrane potential
C. its magnitude does not change from tissue to tissue
D. the membrane potential is negative inside in relation to the outside
E. it is mainly caused by leaking Na+/K+ channels
Answer: D.the membrane potential is negative inside in relation to the outside
304. Gamma amino butyric acid:
A. is an excitatory mediator in the brain
B. it is formed by decarboxylation of glutamates
C. there are three different classes of GABA receptors
D. it is mostly excreted unchanged in the urine
E. is the main mediator in glutamate metabolism
Answer: B.it is formed by decarboxylation of glutamates
305. Substance P:
A. is a carbohydrate
B. is a polypeptide found in intestine and nervous tissue
C. is a beta II amino acid residue mainly found in the liver
D. it is not involved in the neuroendocrine system
E. it is a lipid
Answer: B.is a polypeptide found in intestine and nervous tissue
306. Opioid peptides:
A. are not formed from precursors
B. morphine is an example of opioid peptides
C. they form the opioid receptors in the brain
D. are mainly found in the brain and gastrointestinal
E. they are excreted unchanged almost always
Answer: D.are mainly found in the brain and gastrointestinal
307. Regarding the autonomic nervous system:
A. does not have a reflex arc like somatic nervous system
B. dopamine is the main transmitter
C. cholinergic division of the autonomic nervous system increases activity of the intestinal musculature and increases gastric secretion
D. norepinepherine is metabolised by pseudocholinesterase
E. it is not involved with visceral sensation
Answer: C.cholinergic division of the autonomic nervous system increases activity of the intestinal musculature and increases gastric secretion
308. With respect to blood volume:
A. the greater proportion is present in the arterial system
B. the pulmonary vessels contain 50%
C. the systemic capillaries and arterioles contain 7%
D. the heart contains 20%
E. the aorta contains 20%
Answer: C.the systemic capillaries and arterioles contain 7%
309. Blood pressure:
A. fluctuates in the aorta between 180 and 20mmHg
B. is approaching 0mmHg at the right atrium
C. is half in the pulmonary arteries of that in the aorta
D. is greater in large veins than the vena cava
E. drops significantly at capillary level
Answer: B.is approaching 0mmHg at the right atrium
310. With respect to blood flow:
A. during laminar flow, blood moves at greater velocity adjacent to the vessel wall
B. turbulent flow can occur in long straight vessels
C. during turbulent flow, there is less resistance to flow
D. the tendency for turbulent flow increases inversely with the velocity of blood flow
E. turbulent flow does not normally occur in the aorta
Answer: B.turbulent flow can occur in long straight vessels
311. As a percentage of total blood volume, which of the following values areCORRECT?
A. 40% is in the pulmonary circulation
B. 13% is in the systemic arteries
C. 20% is in the systemic arterioles and capillaries
D. 30% is in the veins
E. none of the above are correct
Answer: B.13% is in the systemic arteries
312. Which is NOT correct about reflex mechanisms acting on the circulation?
A. the baroreceptors in the carotid bodies are stimulated when blood pressure increases
B. the Bainbridge reflex causes increase in heart rate
C. the Cushing reflex is a special central nervous system ischaemic response resulting from increased intracranial pressure
D. the maximum firing per change in pressure of the carotid baroreceptors occurs at a mean arterial pressure of 90mmHg
E. the glossopharyngeal nerve is involved in baroreceptor reflex system
Answer: A.the baroreceptors in the carotid bodies are stimulated when blood pressure increases
313. When the cholinergic vagal fibres to nodal tissues are stimulated:
A. the membrane becomes hyper-polarised
B. the slope of the pre-potential is decreased
C. acetylcholine decreases conductance to Ca++ via muscarinic receptors
D. acetylcholine increases the permeability of nodal tissues to K+ via muscarinic receptors
E. all of the above are true
Answer: E.all of the above are true
314. Heart rate is accelerated by:
A. decreased activity of baroreceptors in the left ventricle
B. increased activity of baroreceptors in the pulmonary circulation
C. increased intracranial pressure
D. expiration
E. increased activity of baroreceptors in the arteries
Answer: A.decreased activity of baroreceptors in the left ventricle
315. Regarding the physical characteristics of the circulation:
A. arterioles have a strong muscular wall but can close completely
B. the arterial system contains the greatest volume of blood at any given time
C. the aorta has a greater total cross sectional area than the venae cavae
D. velocity is directly proportional to the cross sectional area of the blood vessel
E. Reynold’s number represents a measure of laminar blood flow
Answer: A.arterioles have a strong muscular wall but can close completely
316. Regarding a coronary blood flow:
A. systolic blood flow in subendocardial arteries is greater than in the epicardial
B. less than 50% of oxygen is removed during passage when in the resting state
C. the coronary circulation is well supplied by parasympathetic vasodilatory fibres
D. sympathetic vasoconstrictory fibres predominate in epicardial vessels
E. none of the above
Answer: D.sympathetic vasoconstrictory fibres predominate in epicardial vessels
317. Active transport of Na+/K+ accounts for what percentage of energy utilised incells and neurons?
A. 20% cells, 50% neurons
B. 24% cells, 50% neurons
C. 24% cells, 70% neurons
D. 30% cells, 70% neurons
E. 30% cells, 90% neurons
Answer: C.24% cells, 70% neurons
318. Human DNA – what proportion codes for proteins?
A. 3%
B. 13%
C. 23%
D. 33%
E. 53%
Answer: A.3%
319. Comparing nerve fibre types – which is FALSE?
A. C fibres are most susceptible to local anaesthetic
B. A fibres are least susceptible to local anaesthetic
C. B fibres are found preganglionic – autonomic
D. Aδ fibres transmit motor to muscle spindles
E. some C fibres transmit postganglionic sympathetic impulses
Answer: D.Aδ fibres transmit motor to muscle spindles
320. Nicotinic receptors, which is FALSE?
A. are found on sympathetic ganglia
B. are found at the neuromuscular junction
C. are activated by ACh
D. cause activation of a G protein and ↑cAMP
E. cause influx of Na+ via open Na+ channels
Answer: D.cause activation of a G protein and ↑cAMP
321. Serotonin is noted in all but:
A. sexual behaviour
B. obesity
C. platelet aggregation
D. mood
E. vomiting
Answer: A.sexual behaviour
322. With respect to the ascending pathways of sensation within the spinal cord:
A. the ??? columns connect with the medial branches (crosses midline)
B. the central spinothalamic tract carries pain/temp fibres
C. the lateral spinothalamic tract has small fibres medially
D. gracile fasiculatus contains fibres from thoracic and cervical nerves
E. proprioception is transmitted in the lateral spinothalamic tract
Answer: A.the ??? columns connect with the medial branches (crosses midline)
323. With respect to the EEG and brain wave activity – which is FALSE?
A. the α rhythm (adults) has a frequency of 18-30/second
B. infants have a faster β rhythm than adults
C. the frequency of the α rhythm can be decreased with hypoglycaemia, hypothermia and increased ???
D. young adult – 25% sleep is REM sleep
E. REM sleep is characterised by no muscle tone, but increased extraocular movement
Answer: B.infants have a faster β rhythm than adults
324. Which of the following decreases basal metabolic rate?
A. recent ingestion of food
B. stress
C. increased thyroid hormones
D. sleep
E. lactation
Answer: D.sleep
325. Which of the following is an example of a low energy phosphate compound:
A. creatine phosphate
B. UTP
C. acetyl CoA
D. glucose-6 phosphate
E. ATP
Answer: D.glucose-6 phosphate
326. Creatinuria occurs in measurable amounts in all but:
A. women during and after pregnancy and occasionally in non-pregnant women
B. normal men
C. starvation
D. thyrotoxicosis
E. poorly controlled diabetes mellitus
Answer: B.normal men
327. Plasma lipids and lipid transport:
A. apoprotein B48 occurs in VLDL
B. apoprotein B166 and apoprotein C occurs in chylomicrons
C. lecithin cholesterol acyltrasferase is responsible for transferring cholesterol esters from HDL to…
D. chylomicron remnants travel from the intestine within lymphatic fluid in the thoracic duct
E. one half of all LDL molecules is taken up by macrophages and other cells by means other than the LDL receptor
Answer: C.lecithin cholesterol acyltrasferase is responsible for transferring cholesterol esters from HDL to…
328. Adrenal insufficiency may cause all but which of the following?
A. inability to excrete a water load
B. personality changes
C. sodium loss with circulatory insufficiency
D. hypoglycaemia in the presence of fasting
E. leukocytosis
Answer: E.leukocytosis
329. Hyperaldosteronism:
A. causes low plasmic Na+ and high H+
B. retains acid H+ ions and can cause acidosis
C. doesn’t cause oedema due to the escape phenomenon
D. may cause hypocalcaemic nephropathy
E. may be caused by high sodium intake
Answer: C.doesn’t cause oedema due to the escape phenomenon
330. Bone:
A. osteoblasts are multinucleate
B. osteoclasts attach to bone via integins
C. compact bone makes up 60% of a long bone
D. osteoblasts secrete large quantities of type IV collagen and other bone matrix proteins
E. oestrogens inhibit osteoblasts and stimulate osteoclasts
Answer: B.osteoclasts attach to bone via integins
331. Daily water turnover in the gastrointestinal tract:
A. the stomach contributes about 2500ml resorption
B. jejunum resorbs 1300ml of the water
C. the colon absorbs the bulk of the water load
D. the ??? toxin causes achenyl cyclase therefore ↑cAMP and ↑ Clsecretion, ↓ ???
E. stool balance (average) is 500ml
Answer: D.the ??? toxin causes achenyl cyclase therefore ↑cAMP and ↑ Clsecretion, ↓ ???
332. Functional anatomy of the kidney – which is TRUE?
A. 5 million nephrons in each human kidney
B. pores in terestrated kidneys are 170-190nm in diameter
C. mesengial cells are located between the basal lumina and podocytes
D. glomerular membrane permits passage of small (???) neutral substances
E. proximal tubule is 100nm long
Answer: D.glomerular membrane permits passage of small (???) neutral substances
333. Functional anatomy of the kidney – which is FALSE?
A. total length of the nephrons ranges from 45-65mm
B. the macula densa is ??? tubular epithelium of the collecting duct
C. juxtaglomerular cells are found in the walls of the different arteriole
D. intercolated cells are involved in acid secretion and bicarbonate transport
E. total glomerular capillary endothelium across which filtration occurs, is 0.8m2
Answer: B.the macula densa is ??? tubular epithelium of the collecting duct
334. Regulation of renal blood flow – which is FALSE?
A. angiotensin II constricts the afferent arteriole and efferent arteriole
B. noradrenaline constricts intertubular arteries and afferent arterioles
C. dopamine causes vasodilation in renal vessels and natriuresis
D. ACh – renal vasodilation
E. prostaglandins increase blood flow to the cortex and decrease it in the medulla
Answer: A.angiotensin II constricts the afferent arteriole and efferent arteriole
335. All but which of the following cause contraction of the mesengial cells?
A. endothelins
B. angiotensin II
C. ADH
D. noradrenaline
E. cAMP
Answer: E.cAMP
336. All but which of the following are involved in the movement of Na+/Cl- across the apical membrane of the proximal tubules?
A. Na+ / 2Cl- / K+ co-transporter (CT)
B. Na+/ glucose CT
C. Na+/P??? CT
D. Cl- / base exchanges
E. Na+ / H+ exchanges
Answer: A.Na+ / 2Cl- / K+ co-transporter (CT)
337. B nerve fibres:
A. provide motor supply to intrafusal muscle fibres
B. are usually the first fibres affected by local anaesthetics
C. are 12-20umol in diameter
D. are unmyelinated
E. provide pre-ganglionic autonomic supply
Answer: E.provide pre-ganglionic autonomic supply
338. Ionic:
A. movement across an impermeable membrane occurs due to an osmotic gradient
B. equilibrium potential can be determined using the Nernst equation
C. movement across the capillary wall is not affected by the Donnan effect
D. valency determines osmotic effect in an ideal solution
E. forms of weak acids cross cell membranes easily
Answer: B.equilibrium potential can be determined using the Nernst equation
339. Steroid hormones:
A. open ion channels in cell membrane
B. act via cytoplasmic or nuclear receptors
C. increase intracellular cAMP
D. increase tyrosine kinase activity of transmembrane receptors
E. act via a serpentine receptor
Answer: B.act via cytoplasmic or nuclear receptors
340. Cardiac muscle fibres:
A. develop tetany only at very high stimulation frequencies
B. develop less tension when stretched due to decreased actin-myosin overlap
C. can derive only 5% of basal caloric requirement from fat
D. have a T-system located at the A-I junctions
E. remain absolutely refractory until the membrane potential repolarises to – 50mV
Answer: E.remain absolutely refractory until the membrane potential repolarises to – 50mV
341. Glomeruli:
A. minimally filters protein, so plasma protein concentration is not altered
B. are supplied by an extensive anastomotic arterial network
C. lie distal to the juxtaglomerular apparatus
D. each receive approximately 20-25% of resting cardiac output
E. do not filter appreciable albumin since membrane pores are too small
Answer: C.lie distal to the juxtaglomerular apparatus
342. The distal tubule:
A. absorbs most of the filtered sodium ions in the presence of aldosterone
B. absorbs glucose in the normal state
C. absorbs most of the filtered water in the presence of ADH
D. secretes hydrogen via secondary active transport
E. is almost entirely impermeable to urea
Answer: E.is almost entirely impermeable to urea
343. Regarding vitamin D metabolism:
A. 25-hydroxycholecalciferol is converted to 1,25-dihydroxycholecalciferol in the distal convoluted tubule of the kidney
B. 1,25-dihydroxycholecalciferol receptors can be found in skin
C. when calcium levels are high, 24,25-dihydroxycholecalciferol levels are also high
D. transport in plasma is by binding to haemoglobin
E. formation of 25-hydroxycholecalciferol is tightly regulated
Answer: B.1,25-dihydroxycholecalciferol receptors can be found in skin
344. Regarding protein metabolism:
A. NH4 + is formed by reductive deamination of amino acids
B. most of the body’s urea is formed in the kidney
C. phosphorylcreatine is formed in the liver
D. creatinuria occurs normally in children
E. purines and pyrimidines are mainly sourced from dietary intake
Answer: D.creatinuria occurs normally in children
345. Which pattern of laboratory findings in the tale below is most consistent with a diagnosis of diabetes insipidis? 24 Hr Urine Volume Ketones Glucose Protein
A. 4.0 + 0 0
B. 6.2 2+ 4+ 0
C. 1.6 0 0 4+
D. 6.4 0 0 0
E. 5.0 0 0 3+
Answer: D.6.4 0 0 0
346. Angiotensin H causes:
A. greater constriction of efferent than afferent arterioles
B. greater constriction of afferent than efferent arterioles
C. constriction of afferent arterioles only
D. constriction of efferent arterioles only
E. has no effect on arteriolar constriction
Answer: A.greater constriction of efferent than afferent arterioles
347. With regard to tuboglomerular feedback:
A. the GFR increases when flow through the distal tubule increases
B. the macula densa on the afferent arteriole is the sensor
C. the afferent arteriole is constricted by thromboxane A2
D. it is designed to maintain Na+ reabsorption
E. it does not operate in individual nephrons
Answer: C.the afferent arteriole is constricted by thromboxane A2
348. What is the clearance of a substance when its concentration in plasma is 1mg/ml, its concentration in urine is 10mg/ml and the urine flow is 2ml/min
A. 2ml/min
B. 10ml/min
C. 20ml/min
D. 200ml/min
E. clearance cannot be determined from the information given
Answer: C.20ml/min
349. Regarding the proximal tubule, the following statements are true EXCEPT:
A. Na is co-transported out of the tubule with glucose
B. Na is actively transported into the intercellular spaces by Na-K ATPase
C. the cells are characterised by a brush border and tight junctions
D. vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane
E. water moves passively out of the tubule along osmotic gradients
Answer: D.vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane
chapter:
Renal
350. With respect to the counter current system:
A. the loops of Henle act as counter current exchanges
B. solutes diffuse out of vessels conducting blood towards the cortex
C. water diffuses out of ascending vessels
D. water diffuses into the collecting ducts
E. counter current exchange is passive and can operate even if counter current multiplication ceases
Answer: B.solutes diffuse out of vessels conducting blood towards the cortex
351. With regard to the effect of hormones on renal tubules, which is CORRECT?
A. aldosterone increases K reabsorption from the distal tubule
B. angiotensin II increases H+ secretion from the proximal tubules
C. ADH increases water reabsorption in the proximal tubule
D. atrial naturetic peptide decreases Na+ reabsorption from the proximal tubules
E. parathyroid hormone increases phosphate reabsorption
Answer: B.angiotensin II increases H+ secretion from the proximal tubules
352. The thin ascending loop of Henle is:
A. relatively permeable to water
B. relatively impermeable to Na+
C. permeable to both water and Na+
D. relatively impermeable to water
E. relatively impermeable to both water and Na+
Answer: D.relatively impermeable to water
353. Action potential initiation in the sinoatrial and atrioventricular nodes results from:
A. Na+ influx
B. K+ influx
C. Ca++ influx
D. Na+ and Ca++ influx
E. increased K+ conductance
Answer: C.Ca++ influx
354. Regarding isometric ventricular reaction:
A. it occurs late in diastole
B. ventricular filling occurs
C. intraventricular pressure remains constant during this phase
D. it ends when the AV valve close
E. it ends when the AV valve open
Answer: E.it ends when the AV valve open
355. Local vasoconstriction results from:
A. increased potassium concentration
B. increased magnesium concentration
C. increased sodium concentration
D. decrease in pH
E. increased calcium concentration
Answer: E.increased calcium concentration
356. In compensated low output cardiac failure:
A. venous resistance is decreased
B. cardiac contractility is increased
C. mean systemic filling pressure is decreased
D. right atrial pressure is decreased
E. venous return is decreased
Answer: D.right atrial pressure is decreased
357. With regard to ascending to high altitudes:
A. there is a linear decrease in inspired oxygen pressures with increasing altitude
B. the partial pressure of water vapour in moist inspired air decreases with PiO2
C. at 19,200m, barometric pressure = 47mmHg, PiO2 then is approx 9mmHg
D. at peak at Mt Everest, barometric pressure = 380mmHg, PiO2 is approx 70mmHg
E. in permanent residents of the Andes, arterial and venous PO2 is half normal levels
Answer: D.at peak at Mt Everest, barometric pressure = 380mmHg, PiO2 is approx 70mmHg
358. A 28-year-old lady has taken an overdose of sedatives causing her to hypoventilate. Given that her arterial PCO2 is now doubled to 80mmHg, which of the following is most likely to be correct, given that she is breathing room air at normal barometric pressures?
A. arterial PO2 will be approximately 70mmHg
B. arterial PO2 will be approximately 35mmHg
C. arterial Hb O2 saturation will be approximately 50%
D. arterial Hb O2 saturation will be approximately 80%
E. arterial Hb O2 saturation will be approximately 27%
Answer: D.arterial Hb O2 saturation will be approximately 80%
359. Which of the following has the greatest effect on the ability of the blood to transport O2?
A. the capacity of the blood to dissolve O2
B. the amount of Hb in the blood
C. the pH of the plasma
D. the CO2 content of red blood cells
E. the temperature of the blood
Answer: B.the amount of Hb in the blood
360. The Haldane effect describes:
A. the shift to the right of the O2 dissociation curve caused by increased PCO2
B. the enhanced loading of CO2 iii the presence of deoxygenated Hb
C. the shift of chloride ions into red blood cells to balance HCO3 shift from those cells
D. the action of carbonic anhydrase on carbonic acid
E. none of the above
Answer: B.the enhanced loading of CO2 iii the presence of deoxygenated Hb
361. With regard to CO2 carriage in the blood:
A. dissolved CO2 has an insignificant role in the carriage of CO2 in the blood
B. HCO3 production is fast in plasma
C. ionic dissociation of carbonic acid in the red cell is fast without an enzyme
D. the CO2 concentration in blood is independent of the saturation of haemoglobin with oxygen
E. the majority of CO2 is carried in the blood in the forms of dissolved CO2 and carbamino-compounds
Answer: C.ionic dissociation of carbonic acid in the red cell is fast without an enzyme
362. Substances cleared from the circulation by the lungs include all the followingEXCEPT:
A. angiotensin H
B. serotonin
C. leukotrienes
D. bradykinin
E. prostaglandin
Answer: A.angiotensin H
363. With regard to the normal Hb-ox-y-en dissociation curve, which is the most likelyto be CORRECT?
A. when arterial PO2 = 60mmHg, Hb saturation is ∼ 80%
B. when arterial PO2 = 40mmHg, Hb saturation is ∼ 75%
C. when arterial PO2 = 30mmHg, Hb saturation is ∼ 40%
D. acidosis shifts the curve to the left
E. decreased PCO2 shifts the curve to the right
Answer: B.when arterial PO2 = 40mmHg, Hb saturation is ∼ 75%
364. Increased lung compliance is associated with:
A. increasing age
B. increasing pulmonary venous pressure
C. high expanding pressures
D. interstitial fibrosis
E. low lung volumes associated with hypoventilation
Answer: A.increasing age
365. The following physiological events that occur in the body are listed in random sequence:
a. decreased CSF pH
b. increased PaCO2
c. increased CSF PCO2
d. stimulation of medullary chemoreceptors
e. increased PACO2
What is the usual sequence?
A. a, b, c, d, e
B. d, a, c, b, e,
C. c, d, e, b, a,
D. e, b, c, a, d,
E. e, c, b, d, a
Answer: D.e, b, c, a, d,
366. In relation to acid base balance in the body:
A. respiratory compensation in metabolic alkalosis is limited by carotid and aortic chemoreceptor response
B. HCO3 concentration will decrease in compensated respiratory acidosis
C. the rate of renal H+ secretion is not affected by PCO2 in respiratory acidosis
D. chloride excretion is decreased in respiratory acidosis
E. hepatic glutamine synthesis is decreased in chronic metabolic acidosis
Answer: A.respiratory compensation in metabolic alkalosis is limited by carotid and aortic chemoreceptor response
367. The functions of tropomyosin in skeletal muscle include:
A. releasing Ca++ after an action potential
B. sliding on actin to produce shortening
C. binding to myosin during contraction
D. acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin
E. generating ATP which passes to the contractile mechanism
Answer: D.acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin
368. Regarding the autonomic nervous system:
A. does not have a reflex like somatic nervous system
B. has dopamine as the main transmitter
C. has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion
D. neurotransmitter noradrenaline is metabolised by pseudocholinesterase
E. is not involved with visceral sensation
Answer: C.has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion
369. Lymph flow is:
A. an average 500ml/hr into the circulation
B. proportional to interstitial fluid pressure
C. increased with decreased interstitial fluid protein
D. decreased with contraction of muscles
E. decreased with elevated capillary pressure
Answer: B.proportional to interstitial fluid pressure
370. Regarding the intracellular fluid, which is NOT CORRECT?
A. it accounts for 40% of body weight
B. its volume can be estimated using radio-active inulin
C. it contains more protein (in mg/L water) than extracellular fluid
D. the composition of intracellular fluid varies with the nature and function of the cell
E. all of the above are true
Answer: B.its volume can be estimated using radio-active inulin
371. Regarding extracellular volume maintenance:
A. control of sodium balance is the major mechanism maintaining ECF volume
B. a rise in ECF volume stimulates vasopressin secretion
C. osmotic stimuli over-ride volume stimuli in the regulation of vasopressin secretion
D. vasopressin causes Na+ retention by the kidney
E. angiotensin II inhibits aldosterone secretion
Answer: A.control of sodium balance is the major mechanism maintaining ECF volume
372. Regarding renal compensation in respiratory acidosis and alkalosis:
A. the rate of HCO3 reabsorption is inversely proportional to the arterial PCO2
B. in respiratory acidosis, HCO3 reabsorption is reduced
C. changes in plasma chloride concentration are proportional to CHO3 concentration
D. in respiratory alkalosis, renal H+ secretion is increased
E. HCO3 reabsorption depends upon the rate of H+ secretion by the renal tubular cells
Answer: E.HCO3 reabsorption depends upon the rate of H+ secretion by the renal tubular cells
373. Regarding calcium metabolism:
A. approximately 60% of filtered calcium is reabsorbed by the kidney
B. absorption of calcium in the gastrointestinal tract is mainly by passive diffusion
C. the extent of Ca++ binding by plasma proteins is inversely proportionate to the plasma protein level
D. levels of 1,25-dihydroxycholecalciferol fall in the presence of increased plasma Ca++
E. the majority of calcium present in bone is readily exchangeable
Answer: D.levels of 1,25-dihydroxycholecalciferol fall in the presence of increased plasma Ca++
374. Toxins that increase the cyclic AMP content of the intestinal mucosa cause diarrhoea because they:
A. increase Cl- secretion into the intestinal lumen
B. increase Na+ absorption in the small intestine
C. increase K+ secretion into the colon
D. increase Na+/K+ co-transport K+ secretion into the colon
E. none of the above
Answer: A.increase Cl- secretion into the intestinal lumen
chapter:
Nervous System
375. The action potential of a neuron:
A. is initiated by efflux of Na+
B. is terminated by efflux of K+
C. declines in amplitude as it moves along the axon
D. results in transient reversal of the concentration gradient of Na+ across the cell membrane
E. is not associated with any net movement of Na+ or K+ across the cell membrane
Answer: B.is terminated by efflux of K+
376. Which of the following is NOT synthesised in post-ganglionic sympatheticneurons:
A. L-dopa
B. dopamine
C. noradrenaline
D. adrenaline
E. acetylcholine
Answer: C.noradrenaline
chapter:
Nerves and Muscles
377. With reference to the action potential:
A. decreasing the external Na+ concentration increases the size of the action potential
B. decreasing the external K+ concentration decreases the resting membrane potential
C. increasing the external Na+ concentration decreases the resting membrane potential
D. decreasing the external K+ concentration has little effect on the resting membrane potential
E. none of the above are true
Answer: E.none of the above are true
378. In the Erlanger and Gasser classification of nerve fibres:
A. C fibres have the fastest conduction velocity
B. Aγ fibres are responsible for touch and pressure
C. C fibres are most susceptible to local anaesthetics
D. Aα fibres have the fastest conduction velocity and the longest absolute refractory period
E. A fibres are most susceptible to hypoxia
Answer: C.C fibres are most susceptible to local anaesthetics
379. Regarding neurotrophins:
A. NGF and BDNF share the same receptor
B. the structure of the β subunit of NGF resembles that of insulin
C. CNTF is necessary for the growth and maintenance of sympathetic neurons
D. disruption of GDNF by gene knockout causes a marked loss of cutaneous mechanoreceptors
E. none of the above are true
Answer: B.the structure of the β subunit of NGF resembles that of insulin
380. Regarding cardiac muscle:
A. cardiac muscle has high ATPase activity
B. only the α MHC isoform is found in the atria
C. resting membrane potential is about -70mV
D. force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors
E. mutations of the human ether-a-go-go gene causes minks to shake their legs uncontrollably
Answer: D.force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors
381. Which of the following does not decrease smooth muscle membrane potential?
A. acetylcholine
B. stretch
C. cold
D. noradrenaline
E. parasympathetic stimulation
Answer: D.noradrenaline
382. In regard to plasma volume:
A. it contributes to 10% of body weight
B. can easily be measured by radioisotope chromium
C. if the plasma volume is known, the blood volume can be calculated by multiplying100-HCT/100
D. measured by injecting Evans blue
E. the average plasma volume is 500ml
Answer: D.measured by injecting Evans blue
383. Which of the following is FALSE?
A. the ECF represents 20% of body weight
B. the blood volume represents 8% of the body weight
C. the 2/3 of the body water is in ICF
D. 18% of the body weight is protein
E. the transcellular fluids contribute to 5% of the body weight
Answer: E.the transcellular fluids contribute to 5% of the body weight
384. Which of the following is FALSE?
A. diffusion depends on concentration gradient of the solutes
B. osmotic pressure of a solution is inversely related to the volume of the solution
C. when 5% dextrose is infused, it becomes hypotonic to the plasma in the body
D. osmolality is defined as osmotically active particles in 1L of solution
E. osmolality is defined as a number of osmotically active particles in 1kg of solvent
Answer: D.osmolality is defined as osmotically active particles in 1L of solution
385. Regarding cell membrane, which of the following is FALSE?
A. the diameter of the cell membrane is about 7.5nm
B. 50% of the cell membrane is made up of proteins
C. the main lipids of the cell membrane are phospholipids
D. the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane
E. the proteins in the cell membrane function as carriers, ion channels, enzymes and receptors
Answer: D.the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane
386. Regarding mitochondria, which of the following is TRUE?
A. 99% of mitochondrial proteins are products of mitochondrial DNA
B. the outer membrane of the mitochondria is folded to form cristae
C. the space between the outer and inner mitochondrial space is called matrix space
D. it is the sperm which contributes to the formation of mitochondria in the zygote
E. the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space
Answer: E.the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space
387. Which is FALSE?
A. fast fibres have small number of mitochondria
B. fast fibres are called white muscles
C. the glycolic processes are more important in energy supply in fast fibres
D. slow fibres are also called red fibres
E. fast fibres have more extensive blood supply than slow fibres
Answer: E.fast fibres have more extensive blood supply than slow fibres
388. Smooth muscles differ from skeletal muscle by:
A. not having actin/myosin
B. not having striated appearance
C. not using ATP for contraction
D. not using Ca2+ for contraction
E. not having sarcoplasmic reticulum
Answer: B.not having striated appearance
389. Which of the following is absent in smooth muscle?
A. tropomysin
B. actin
C. myosin
D. troponin
E. mitochondria
Answer: D.troponin
390. The highest number of voltage gated Na+ channels are found in:
A. initial segment of axon
B. nodes of Ranvier
C. cell body
D. terminal buttons
E. myeline sheath
Answer: A.initial segment of axon
391. Which of the following nerve fibres is most susceptible to hypoxia?
A. group B
B. group C
C. group A – α
D. dorsal root
E. somatic motor
Answer: A.group B
392. Which of the following is most susceptible to pressure?
A. group A – motor
B. group C
C. group B
D. pre ganglionic-autonomic
E. muscle spindle fibres
Answer: A.group A – motor
393. Regarding nerve action potential, which is TRUE?
A. normal resting membrane potential is -40mV
B. initial rapid depolarisation is due to rapid influx of Ca2+ via fast channels
C. during depolarisation, Na+ permeality is greater than K+ permeality
D. hyperpolarisation is due to continuous opening of Na+ channels
E. plateau is formed by slow Ca2+ channels
Answer: C.during depolarisation, Na+ permeality is greater than K+ permeality
394. Which is FALSE regarding secondary active transport?
A. it always transports substances in one direction
B. energy required is obtained by Na+ /K+ ATPase pump
C. a good example is Na+ / glucose co-transport
D. Na+ / Ca2+ antiport is an example of secondary active transport
E. secondary active transport occurs in renal tubules
Answer: A.it always transports substances in one direction
395. Which is TRUE?
A. steroids act via cAMP
B. insulin acts via IP3
C. EGF+ erythropoietin act via cAMP
D. thyroid hormones act via G proteins
E. retinoic acid act via intracellular receptor → transcription of genes
Answer: E.retinoic acid act via intracellular receptor → transcription of genes
396. Na+ / K+ ATPase pump – which is FALSE?
A. it is electrogenic in nature
B. it is important in maintaining cell volume
C. plays a major role in secondary active transport
D. it is the main factor which determine the resting membrane potential
E. it is an example of primary active transport
Answer: D.it is the main factor which determine the resting membrane potential
397. Regarding serotonin:
A. the highest concentration is in the brain
B. formed by hydroxylation and decarboxylation of tyrosine
C. catabolised by COMT
D. some receptors are ion channels
E. mediates smooth muscle relaxation
Answer: D.some receptors are ion channels
398. GABA:
A. decreases Cl- conductance
B. is broken down by glutamate decarboxylase (GA????)
C. there are five receptor subtypes
D. benzodiazepines bind to the β subunit of the GABA receptor
E. is involved in 20% of CNS synapses
Answer: E.is involved in 20% of CNS synapses
399. Which is NOT present in high concentrations, at the active zone of synapses?
A. syntaxin
B. catecholamine vesicles
C. neuropeptide vesicles
D. synaptobrevin
E. calcium channels
Answer: C.neuropeptide vesicles
400. Which is not a ligand-gated ion channel?
A. nicotinic receptor
B. GABAA receptor
C. glycine receptor
D. NMDA receptor
E. 5-HT1 receptor
Answer: E.5-HT1 receptor
401. Which drug is NOT involved in facilitating Cl- conductance?
A. benzodiazepines
B. progesterone
C. oestrogen
D. barbiturates
E. alcohol
Answer: C.oestrogen
402. Regarding skeletal muscle:
A. isotonic contraction does no work
B. calcium is released from troponin during contraction
C. the resting membrane potential is -70mV
D. treppe occurs in skeletal muscle only
E. white muscle has short twitch durations
Answer: E.white muscle has short twitch durations
403. Regarding cardiac muscle:
A. gap junctions provide high resistance bridges
B. T system of tubules located at A-I junctions
C. calcium binds to calmodulin
D. tetany is not possible due to the latch bridge mechanism
E. ↑cAMP leads to ↑ force of contraction
Answer: E.↑cAMP leads to ↑ force of contraction
404. Regarding smooth muscle:
A. tropomyosin is absent
B. the resting membrane potential is -90mV
C. there is a highly developed sarcoplasmic reticulum
D. there are no spike potentials
E. dense bodies are attached to the cell membrane
Answer: E.dense bodies are attached to the cell membrane
405. Regarding synapses:
A. large vesicles contain ACh
B. Na+ influx triggers fusion / exocytosis of vesicles
C. I PSP can be produced by closing K channels
D. the synaptic cleft is 100-150nm
E. neurotransmitters migrate down the axon by fast axoplasmic transport
Answer: E.neurotransmitters migrate down the axon by fast axoplasmic transport
406. Regarding acetylcholine:
A. it is oxidised to choline and acetate by acetylcholinesterase
B. nicotinic receptors are blocked by atropine
C. it is the main excitatory transmitter in the spinal cord
D. it is secreted by the adrenal medulla
E. tetanus blocks its release at the NMJ
Answer: E.tetanus blocks its release at the NMJ
407. Regarding synaptic structure / function:
A. small clear vesicles in the presynaptic tunnel contain catecholamines
B. tetanus toxin causes spastic paralysis by blocking release of ACh at NMJ
C. chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses
D. the EPSP is an all-or-none response
E. An I-PSP can be produced by localised increase in membrane permeability to Cl-
Answer: C.chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses
408. Transmitters – all are true EXCEPT:
A. angiotensin II is a neurotransmitter of the polypeptidillars
B. glutamate is an inhibitory amino acid
C. glucagons is found in hypothalamus and retina
D. vasopressin is found in posterior pituitary, medulla, spinal cord
E. serotonin is an amine
Answer: B.glutamate is an inhibitory amino acid
409. Neurotransmitters:
A. atropine blocks effect of acetylcholine at ???? receptor
B. reaction between active acetate and choline is catalysed by acetylcholinesterase
C. nicotinic cholinergic receptors are serpentine receptors
D. the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa
E. MAOA is found in nerve endings and platelets
Answer: D.the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa
chapter:
Nervous System
410. Regarding muscle spindles:
A. are composed of extrafusal fibres
B. receive δ efferents
C. all subtypes send afferents via “flower spray” ended 1a nerves
D. nuclear chain fibres show dynamic response
E. afferent discharge decreased with muscle stretch
Answer: B.receive δ efferents
411. Regarding the dorsal column:
A. carries ipsilateral pain and temperature
B. ascends to the nuclei gracillis and ?????
C. receives efferents from contralateral stimuli
D. sacral efferents lie laterally
E. runs anteriorly in the cord
Answer: B.ascends to the nuclei gracillis and ?????
412. Temperature sensation:
A. respond to compartitive temp gradient ??? skin
B. cold receptors predominate
C. warm receptors respond 30° – 100°
D. afferents carried via the dorsal column
E. warm and cold afferents carried via Ad fibre
Answer: B.cold receptors predominate
413. Regarding visual receptors:
A. rods predominate in the jovea
B. rhodopsin is the primary pigment of rods
C. lie anterior (superficial) to their neural pathway
D. colour blindness is an autosomal recessive gene
E. supplied by retinal vessels
Answer: B.rhodopsin is the primary pigment of rods
414. Regarding sound and hearing:
A. high pitched sounds are detected at the apex of the cochlear
B. Harr cells are bathed in endolymph
C. defected by hair cells found within the tectorium membrane
D. 95% of afferent neurones → outer ??? cells
E. supplied by retinal vessels
Answer: E.supplied by retinal vessels
415. Regarding noradrenergic stimulation:
A. miosis occurs
B. increases blood flow to the skin
C. increases thresholds in the reticular formation
D. causes erection in males
E. elevates free fatty acid levels
Answer: D.causes erection in males
416. Regarding cholinergic stimulation:
A. causes amylase secretion from salivary glands
B. decreases secretion from pancreatic ?????
C. relaxes the gallbladder
D. has no effect on renal arterioles
E. relaxes bronchial smooth muscle
Answer: D.has no effect on renal arterioles
417. The emotional component to pain is due to activation of:
A. post central gyrus
B. sylvian fissure
C. hippocampus
D. cingulated cortex
E. calcavine fissure
Answer: A.post central gyrus
418. The chemical agent that initiates impulses in pain fibres is:
A. ATP
B. substance P
C. Ca2+
D. H+
E. K+
Answer: B.substance P
419. Regarding thermoceptors:
A. there are more warm receptors than cold receptors
B. cold receptors respond to 10-38°C
C. afferents for cold receptors are C fibres only
D. afferents found in the ventral spinothalamic tract
E. respond to the temperature gradient across the skin
Answer: C.afferents for cold receptors are C fibres only
420. Regarding body temperature:
A. humans are poikilothermic
B. oral temperature is usually higher than rectal temperature
C. it is usually lowest at 6am
D. children have more precise temperature regulation
E. emotion has no effect on core temperature
Answer: E.emotion has no effect on core temperature
421. Regarding the hypothalamus:
A. it has neural connections with the anterior pituitary gland
B. it integrates the vomiting reflex
C. the anterior hypothalamus responds to cold
D. it controls circadian rhythms via the supraoptic nuclei
E. it has osmoreceptors in the anterior hypothalamus to stimulate thirst and vasopressin release
Answer: B.it integrates the vomiting reflex
422. Regarding the vomiting reflex, which is INCORRECT?
A. it is integrated by the medilla
B. breath is held in expiration
C. the glottis closes
D. it involves salivation
E. there are afferents from vestibular nuclei
Answer: B.breath is held in expiration
423. Herring bodies are:
A. nuclei of the hypothalamus
B. secretory granules in the posterior pituitary
C. circumventricular organs
D. neurons connecting vestibular nuclei with the vomiting centre
E. vesicles containing ACTH, TSH, GH, FSH, CH and PRL
Answer: C.circumventricular organs
424. The neurotransmitter secreted by primary afferent fibres for severe pain is:
A. glutamate
B. acetylcholine
C. substance P
D. opioid peptides
E. noradrenaline
Answer: D.opioid peptides
425. Regarding rods and cones:
A. Na+ channels are closed in the dark
B. light striking the outer segments results in a depolarising receptor potential
C. the receptor potentials are all-or-nothing
D. rhodopsin is a serpentine receptor
E. acetylcholine is released from the synaptic terminal
Answer: C.the receptor potentials are all-or-nothing
426. The visual cortex is situated at the:
A. parieto-occipital sulcus
B. cuneus
C. calcanine fissure
D. lateral geniculate body
E. angular gyrus
Answer: D.lateral geniculate body
427. In the visual pathway:
A. the lateral geniculate bodies are made up of t layers
B. fibres for reflex pupillary constriction leave the optic nerve at the optic chiasm
C. pituitary tumours can cause homonymous hemianopia
D. macular sparing may or may not occur with lesions in the geniculocalcanine tract
E. binasal visual field fibres decussate at the opticchiasm
Answer: D.macular sparing may or may not occur with lesions in the geniculocalcanine tract
428. When a normal innervated skeletal muscle is stretched, the initial response is contraction, but with increasing stretch, the muscle suddenly relaxes because:
A. with strong stretch, the efferent discharge is decreased
B. with strong stretch, the discharge from the annulospiral endings of afferent nerve fibres is inhibited
C. with strong stretch, there is decreased activity in the afferent nerve fibres from the Golgi tendon organs
D. with strong stretch, there is increased activity in the afferent nerve fibres from the Golgi tendon organs
E. because of reciprocal innervation, there is increased discharge in the afferent nerve fibres from the antagonists to the stretched muscle
Answer: E.because of reciprocal innervation, there is increased discharge in the afferent nerve fibres from the antagonists to the stretched muscle
429. In a polysynaptic reflex, which of the following happen when the strength of the adequate stimulus is increased?
A. the amplitude of the motor response is increased
B. the motor response spreads to include other muscles and even other limbs
C. there is increased inhibition of stretch reflexes
D. the duration of the motor response increases
E. all of the above are true
Answer: A.the amplitude of the motor response is increased
430. A tumour causing external compression to the anterior cervical spinal cord would beexpected to:
A. impair pressure and pain sensation mostly from sacral and lumbar areas
B. impair fine touch and vibration mostly from sacral and lumbar areas
C. impair pain only from cervical areas
D. impair vibration sense only from cervical areas
E. impair joint position from sacral areas only
Answer: D.impair vibration sense only from cervical areas
431. Which of the following need to be intact for normal stereognosis:
A. dorsal columns
B. parietal lobe
C. pressure pathways
D. all of the above
E. none of the above
Answer: B.parietal lobe
432. Bitemporal hemianopia is most likely to be caused by a lesion at the:
A. optic nerve
B. optic chiasm
C. optic tract
D. optic radiation
E. visual cortex
Answer: D.optic radiation
433. Regarding temperature regulation, which is NOT true?
A. the anterior hypothalamus contains temperature sensitive cells
B. shivering is activated by the posterior hypothalamus
C. the anterior hypothalamus controls mechanisms activated by heat
D. horripilation acts to increase heat production
E. fever is produced by the action of cytokines on the hypothalmus
Answer: E.fever is produced by the action of cytokines on the hypothalmus
434. When a visual stimulus falls on a given point in the retina for a long time:
A. the image becomes more clearly focused
B. there is adaptation in the visual cortex
C. the discharge rate in the bipolar cells increases
D. the pupils constrict
E. the image fades and disappears
Answer: A.the image becomes more clearly focused
435. Which of the following affect visual activity?
A. cataracts
B. vitamin A deficiency
C. astigmatism
D. contrast between stimulus and background
E. all of the above
Answer: E.all of the above
436. The ‘tympanic reflex’:
A. is activated by foreign bodies in the external auditory canal
B. results in vertigo
C. is activated by high-pitched sounds only
D. results in the decreased transmission of sound
E. none of the above
Answer: D.results in the decreased transmission of sound
437. Regarding pain transmission, which is NOT true?
A. ‘fast pain’ fibres are Aδ fibres
B. ‘slow pain’ fibres are C fibres
C. substance P is the central transmitter
D. all impulses pass through the central horn
E. pain sensation results from over-stimulation of other sensory modalities
Answer: E.pain sensation results from over-stimulation of other sensory modalities
438. Which is NOT a part of the basal ganglia?
A. caudate nucleus
B. cuneate nucleus
C. substantia nigra
D. putamen
E. globus pallidum
Answer: B.cuneate nucleus
439. With regard to pain pathways, all the following are true EXCEPT:
A. peripheral afferents are transmitted along A (delta) and C fibres
B. an intact cerebral cortex is necessary for pain sensation
C. the synaptic transmitter released by primary afferent fibres subserving pain is substance P
D. afferent fibres subserving pain sensation from viscera reach the CNS by both sympathetic and parasympathetic pathways
E. the sensory organs for pain are marked nerve endings
Answer: B.an intact cerebral cortex is necessary for pain sensation
440. Cerebellar disease in humans causes all of the following EXCEPT:
A. dysmetria
B. scanning speech
C. lead pipe rigidity
D. rebound phenomenon
E. dysdiadockokinesia
Answer: C.lead pipe rigidity
441. The righting reflex is pronounced after sectioning of the neural axis above whichlevel:
A. spinal cord
B. medulla
C. mid-brain
D. subcortical nuclei
E. all above intact but decerebellate
Answer: C.mid-brain
442. Regarding muscle spindles, which is NOT true?
A. they contain nuclear bag and nuclear chain fibres
B. they receive a motor supply via Aγ fibres
C. they discharge more upon stretching of the muscle
D. they are responsible for the inverse stretch reflex
E. they relay information to the cord via Ia fibres
Answer: D.they are responsible for the inverse stretch reflex
443. The action potential of a neuron (influx):
A. is initiated by efflux of Na+
B. is terminated by efflux of K+
C. declines in amplitude as it moves along the axon
D. results in transient reversal of the concentration (?electrical) gradient of Na+ across the cell membrane
E. is not associated with any net movement of Na+ of K+ across the cell membrane
Answer: E.is not associated with any net movement of Na+ of K+ across the cell membrane
444. The functions of tropomyosin in skeletal muscle include:
A. releasing Ca2+ after an action potential
B. sliding on actin to produce shortening
C. binding to myosin during contraction
D. acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin
E. generating ATP which passes to the contractile mechanism
Answer: D.acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin
445. Regarding the autonomic nervous system:
A. it does not have a reflex arch like the somatic nervous system
B. it has dopamine as the main transmitter
C. it has cholinergic division which increases activity of the intestinal musculature and increases gastric excretion
D. neurotransmitter noradrenaline is metabolised by pseudocholinesterase
E. it is not onvolved with visceral sensation (?involved)
Answer: C.it has cholinergic division which increases activity of the intestinal musculature and increases gastric excretion
446. Which of the following does NOT act via an intracellular receptor?
A. atrial natriuretic peptide
B. cortisol
C. thyroxine
D. aldosterone
E. retinoic acid
Answer: E.retinoic acid
447. Steps involved in skeletal muscle contraction include all of the following EXCEPT:
A. binding of acetylcholine to nicotinic receptors
B. increased Na+ and K+ conductance in end plate membrane
C. spread of depolarisation along T tubules
D. binding of calcium to troponin T, with uncovering of its actin-myosin binding site
E. CTP (cytidine triphosphate)
Answer: E.CTP (cytidine triphosphate)
448. Regarding the resting membrane potential in peripheral nerves:
A. membrane permeability of potassium ions via K+ leak channels produces the resting potential
B. a decrease in extracellular Ca2+ decreases excitability
C. decreasing external Na+ concentration lowers the resting membrane potential
D. changing the external Na+ concentration has no effect on the action potential
E. decreasing the external K+ concentration increases the resting membrane potential
Answer: A.membrane permeability of potassium ions via K+ leak channels produces the resting potential
449. Regarding excitation-contraction coupling in skeletal muscle, which statement isINCORRECT?
A. calcium ions bind to troponin T
B. troponin I – tropomyosin complex constitutes a “relaxing protein”
C. each cycle of attachment and detachment shortens muscle length by about 1%
D. ATP is the immediate source of energy
E. globular head of myosin – II possesses actin binding site
Answer: A.calcium ions bind to troponin T
450. Microglia:
A. are involved with myelin production
B. are scavenger cells
C. are performed in the brain
D. are important in GABA uptake
E. induce capillaries to form tight junctions and thus the blood brain barrier
Answer: B.are scavenger cells
451. The action potential:
A. is always monophasic
B. has an absolute refractory period lasting to the start of the after depolarisation
C. has a relative refractory period lasting until repolarisation is complete
D. requires opening of voltage gated Na+ channels
E. results in ↓ K+ conductance
Answer: D.requires opening of voltage gated Na+ channels
452. Which of the following nerve fibre types is MOST sensitive to hypoxia?
A. A-alpha
B. A-beta
C. A-delta
D. B
E. C
Answer: D.B
453. Regarding smooth muscle contractility, which statement is INCORRECT?
A. increased by acetylcholine
B. decreased by activation of phospholipase C
C. increased by cold
D. decreased by cAMP
E. increased by stretch
Answer: B.decreased by activation of phospholipase C
454. Regarding smooth muscle, which statement is INCORRECT?
A. multi-unit smooth muscle is present in the jejunum
B. may exhibit pacemaker potentials
C. mechanical response is much slower than striated muscle
D. the membrane potential is unstable
E. functions as a syncytium in viscera
Answer: A.multi-unit smooth muscle is present in the jejunum
455. A sarcomere:
A. contains two separate halves of an A-band and an I-band
B. is the space between two A-bands
C. is between two Z-lines
D. has the T-system of the sarcotubular system at sarcomere junctions
E. contracts when the troponin molecule binds to the myosin head
Answer: C.is between two Z-lines
456. Type I muscle fibres:
A. have fast glycolytic rates
B. have low oxidative capacity
C. are more commonly found in muscle that performs explosive work
D. do not have a very high glycolytic capacity
E. are not abundant in endurance athletes
Answer: D.do not have a very high glycolytic capacity
457. Regarding cardiac muscle, which statement is INCORRECT?
A. resting membrane potential is about -90mV
B. energy source at rest is mainly fat
C. mechanical response lasts about twice as long as electrical response
D. tetanus cannot occur
E. it has an all-or-nothing contractile response
Answer: C.mechanical response lasts about twice as long as electrical response
458. Regarding denervation:
A. it causes skeletal muscle hypertrophy
B. does not lead to fibrillation
C. causes hyposensitivity to acetylcholine in skeletal muscle
D. smooth muscle is able to contract if it occurs in vivo
E. causes fasciculations
Answer: D.smooth muscle is able to contract if it occurs in vivo
459. Which of the following nerve fibre types is MOST sensitive to pressure?
A. A-beta
B. A-gamma
C. A-delta
D. B
E. C
Answer: A.A-beta
460. Regarding decerebration:
A. decerebration produces spinal shock
B. decerebrate rigidity is spasticity due to diffuse facilitation of stretch reflex
C. there is increased rate of discharge in the α afferent neurons
D. spasticity produced by decerebration is more marked in flexor muscles
E. most commonly produces upper limb flexion and lower limb extension
Answer: B.decerebrate rigidity is spasticity due to diffuse facilitation of stretch reflex
461. Which of the following nerve fibre types has the LARGEST diameter?
A. C
B. A-alpha
C. B
D. A-gamma
E. A-beta
Answer: B.A-alpha
462. The following are NOT energy sources of muscle:
A. phosphorylcreatine
B. fatty acids
C. glucose
D. glycogen
E. creatine
Answer: E.creatine
463. Regarding sensory organ stimulation, which statement is INCORRECT?
A. adaptation occurs over the temperature range 20-40°C
B. pain is sensed by naked nerve endings
C. pacinian corpuscles are rapidly adapting touch-pressure receptors
D. naked nerve endings can detect all four cutaneous sensory modalities
E. any given nerve ending can signal more than one sensory modality
Answer: E.any given nerve ending can signal more than one sensory modality
464. Regarding neurotransmitters, which of the following is INCORRECT?
A. glutamate is excitatory
B. GABA is inhibitory at presynaptic neurons
C. glycine is excitatory at postsynaptic neurons
D. GHB (gamma hydroxybutyrate) is inhibitory
E. aspartate is excitatory
Answer: C.glycine is excitatory at postsynaptic neurons
465. The stretch reflex:
A. is classically initiated by tapping on the quadriceps muscle
B. is initiated by stretch of the muscle
C. involves impulses being conducted from the muscle spindle to the motor cortex
D. involves extrafusal fibres stimulating annulospiral and flowerspray sensory fibres
E. involves gamma afferents of leksell
Answer: B.is initiated by stretch of the muscle
466. Which of the following is NOT present in smooth muscle cells?
A. actin
B. myosin-II
C. tropomyosin
D. almodulin
E. troponin
Answer: E.troponin
467. Regarding the structure of cardiac muscle, which statement is INCORRECT?
A. T-system lies at Z-lines
B. functions as a syncytium due to the presence of tight junctions
C. intercalated discs occur at Z-lines
D. contains large numbers of elongated mitochondria
E. thin filaments include troponin T, C and I
Answer: B.functions as a syncytium due to the presence of tight junctions
468. Regarding the cardiac muscle action potential, which statement is INCORRECT?
A. sodium ions enter via “fast” channels in phase 0
B. chloride ions may enter cell during phase 1
C. sodium ions enter via “slow” channels in phase 2
D. relative refractory period ends in phase 3
E. class I anti-arrhythmics reduce the slope of phase 4
Answer: A.sodium ions enter via “fast” channels in phase 0
469. Which of the following nerve fibre types represents the efferent limb of the musclespindle reflex arc?
A. A-alpha
B. A-beta
C. A-gamma
D. A-delta
E. B
Answer: C.A-gamma
470. Regarding neuromuscular transmission, which statement is INCORRECT?
A. smooth muscle cells possess synapses en passant
B. about 10 times as much acetylcholine as is required is released at skeletal muscle neuromuscular junctions
C. antibodies can develop to calcium channels in nerve endings at neuromuscular junctions
D. more than one nerve fibre ends on each end-plate in skeletal muscle
E. acetylcholine is released by exocytosis
Answer: D.more than one nerve fibre ends on each end-plate in skeletal muscle
471. Regarding the structure of skeletal muscle, which statement is INCORRECT?
A. thick filaments consist of myosin
B. actin forms a double helix
C. thin filaments include tropomyosin
D. troponin-I inhibits interaction between actin and myosin
E. T-system lies at Z-lines
Answer: E.T-system lies at Z-lines
472. Which of the following nerve fibre types has the fastest conduction velocity?
A. B
B. A-delta
C. A-beta
D. A-gamma
E. C
Answer: C.A-beta
473. Regarding the nerve fibre action potential, which statement is INCORRECT?
A. does not involve calcium ions
B. after-depolarisation commences when repolarisation is 70% complete
C. total number of ions involved is minute compared to the total number present
D. spike potential peaks at sodium equilibrium potential
E. firing level (threshold) is at about -55mV
Answer: D.spike potential peaks at sodium equilibrium potential
474. Which of the following nerve fibre types is MOST sensitive to local anaestheticblockade?
A. A-alpha
B. A-gamma
C. A-delta
D. B
E. C
Answer: E.C
475. Regarding neurotoxins, which statement is INCORRECT?
A. tetrodotoxin is a sodium channel blocker
B. tetraethylammonium is a potassium channel blocker
C. tetanospasmin interferes with GABA release
D. botulinum toxin blocks release of acetylcholine
E. latrotoxin causes explosive release of acetylcholine
Answer: C.tetanospasmin interferes with GABA release
476. Regarding conduction of nerve impulses, which statement is INCORRECT?
A. it is an active, self-propagating process
B. salutatory conduction occurs in unmyelinated neurons
C. axons can conduct impulses in either direction
D. conduction velocity is proportional to nerve fibre diameter
E. “current sink” occurs in neuronal cell membrane ahead of impulse
Answer: B.salutatory conduction occurs in unmyelinated neurons
477. B nerve fibres transmit impulses of which modality?
A. proprioception
B. preganglionic autonomic
C. temperature
D. postganglionic sympathetic
E. somatic motor
Answer: B.preganglionic autonomic
478. Regarding nerve fibres, which statement is INCORRECT?
A. resting membrane potential is about -90mV
B. action potentials are generated at the initial segment in spinal motor neurons
C. myelin produces up to 50 times faster conduction of impulses
D. membrane is more permeable to potassium than sodium at rest
E. sodium channels are highly concentrated at the nodes of ranvier
Answer: A.resting membrane potential is about -90mV
479. Regarding skeletal muscle, which statement is INCORRECT?
A. resting membrane potential is about -90mV
B. resting length is the length at which active tension in the muscle is maximal
C. total glycogen stored is about 0.4kg
D. energy source at rest is mainly glucose
E. resting heat production is due to basal metabolic processes
Answer: D.energy source at rest is mainly glucose
480. Which of the following nerve fibre types has the LEAST myelin?
A. A-alpha
B. A-beta
C. A-gamma
D. B
E. C
Answer: E.C
481. A-alpha nerve fibres transmit impulses of which modality?
A. proprioception
B. pain
C. pressure
D. touch
E. motor to muscle spindles
Answer: A.proprioception
482. Unmyelinated neurons:
A. do not have Schwann cells associated with them
B. display salutatory conduction
C. constitute most of the cell population in the human central nervous system
D. do not occur in humans
E. none of the above are true
Answer: E.none of the above are true
483. In skeletal muscle:
A. thick filaments which are made up of myosin and tropomyosin are lined up to form A bands
B. the dark A band has a light H band in its centre which in turn has an M line in its middle
C. think filaments are made up of actin, tropomyosin and troponin and form the H band
D. Z lines are connected to the thick filaments
E. during contraction, the width of the A band reduces
Answer: C.think filaments are made up of actin, tropomyosin and troponin and form the H band
484. Dorsal root (type C) fibres:
A. conduct proprioception
B. are amongst the largest of the nerve fibres
C. are the fibres most susceptible to hypoxia
D. administration of lignocaine suppresses transmission in C fibres before affecting A fibres
E. are myelinated
Answer: D.administration of lignocaine suppresses transmission in C fibres before affecting A fibres
485. Saltatory conduction:
A. only occurs in myelinated neurons
B. is slower than non-saltatory conduction
C. is unaffected by local anaesthetics
D. does not occur with anti-dromic conduction
E. is directly proportional in rate to the size of the action potential
Answer: A.only occurs in myelinated neurons
486. A motor unit is made up of:
A. a flexor muscle and an extensor muscle
B. a single skeletal muscle and all the motor neurons that supply it
C. a single motor neuron and all the muscle fibres it innervates
D. a large bundle of muscle fibres
E. all the motor neurons in which responses are observed after maximal stimulation
Answer: C.a single motor neuron and all the muscle fibres it innervates
487. The role of calcium in excitation/contraction couple in skeletal muscle is:
A. by binding troponin C it uncovers the binding site of actin to interact with the myosin head
B. by binding troponin I, it uncovers the binding site of actin to interact with the myosin head
C. by binding to tropomyosin, it allows troponic to bind to myosin
D. by binding to troponin C, it allows the myosin head to disengage resulting in relaxation
E. it causes depolarisation to spread along the tubules
Answer: A.by binding troponin C it uncovers the binding site of actin to interact with the myosin head
488. A decrease in extracellular K+:
A. makes the resting membrane more negative in nerve cells
B. causes a similar effect in nerve cells as a decrease in extracellular Na+
C. has little effect in nerve cell membrane potential
D. may decrease nerve cell action potential size
E. cause a similar effect in nerve cells as an increase in extracellular Ca++
Answer: E.cause a similar effect in nerve cells as an increase in extracellular Ca++
489. Tetanic contraction of skeletal muscle:
A. occurs because of the short refractory period of skeletal muscle
B. is due to increased calcium available for binding to troponin C
C. enables a tension development of approximately four times that of individual twitch contraction
D. occurs only with isometric contractions
E. has the same mechanism of that of cardiac muscle
Answer: C.enables a tension development of approximately four times that of individual twitch contraction
490. With respect to nerve fibre types:
A. the speed on conduction is inversely proportional to the diameter of the fibre
B. C fibres are more susceptible to local anaesthetics than A fibres
C. Aδ fibres are concerned primarily with somatic motor function
D. pain may be relayed by all fibre types
E. Aδ fibres are efferent only
Answer: B.C fibres are more susceptible to local anaesthetics than A fibres
491. In visceral smooth muscle:
A. Ca2+ for contraction is released from sarcoplasmic reticulum
B. membrane potential has a resting value of -90mV
C. the excitation contraction coupling time is rapid (<10ms)
D. muscle contracts when stretched in absence of innervation
E. binding of acetylcholine to nicotine receptors increases Ca2+ influx
Answer: D.muscle contracts when stretched in absence of innervation
492. Inhibitory post synaptic potentials involve:
A. localised increase in membrane permeability to Na+
B. localised decrease in membrane permeability to Cl-
C. localised increase in membrane permeability to PO4
D. localised increase in membrane permeability to Cl-
E. localised decrease in membrane permeability to K+
Answer: D.localised increase in membrane permeability to Cl-
493. In skeletal muscle relaxation:
A. there is a spread of depolarisation along T tubules
B. Ca2+ is released from troponin
C. there is increase Na+ and K+ conduction in the end plate membranes
D. a resting membrane potential of -65mV is finally reached
E. Mg2+ has a crucial role
Answer: B.Ca2+ is released from troponin
494. Regarding synapses:
A. the synaptic cleft is 30-50mm wide
B. transmitters are released from synaptic knobs secondary to Na+ triggers
C. the amount of transmitter released is proportionate to Ca2+ efflux
D. acetylcholine is present in granulated vesicles in synaptic knob
E. the EPSP is caused by Na+ influx
Answer: E.the EPSP is caused by Na+ influx
495. Which of the following is inhibitory neurotransmitter?
A. gallamine
B. acetylcholine
C. glutamate
D. glycine
E. aspartate
Answer: D.glycine
496. Which of the following nerves is NOT of fibre type A?
A. proprioception
B. touch
C. motor to muscle spindles
D. somatic motor
E. dorsal root pain and temperature
Answer: E.dorsal root pain and temperature
497. Which nerve fibre is MOST susceptible to local anaesthetics?
A. proprioception
B. touch
C. motor to muscle spindles
D. somatic motor
E. dorsal root pain and temperature
Answer: E.dorsal root pain and temperature
498. Which nerves have the biggest diameter and faster conduction velocity?
A. group A alpha
B. group A beta
C. group A gamma
D. group A delta
E. group C
Answer: A.group A alpha
499. In excitation-contraction of skeletal muscle, calcium binds to:
A. tropomyosin
B. myosin
C. troponin I
D. troponin C
E. troponin T
Answer: D.troponin C
500. Myosin binding sites on actin are normally covered by:
A. troponin I
B. troponin C
C. troponin T
D. tropomyosin
E. ryanodine molecule
Answer: D.tropomyosin
501. With regard to skeletal muscle, which is INCORRECT?
A. the terminal cisterns of sarcoplasmic reticulum lie in contact with T tubules
B. the T tubules surround the muscle at its Z lines
C. the Z line lies within the I band
D. the M line is due to a central bulge in each of the thick filaments
E. the area between two adjacent Z lines is called a sarcomere
Answer: B.the T tubules surround the muscle at its Z lines
502. Noradrenaline:
A. is the main neurotransmitter of the parasympathetic nervous system
B. acts as sympathetic neuromuscular junctions in skeletal muscle and vascular smooth muscle
C. is secreted by the adrenal medulla
D. causes pupillary constriction
E. reduces blood pressure
Answer: C.is secreted by the adrenal medulla
503. Acetylcholine:
A. is a major neurotransmitter in the spinal cord
B. is degraded within the neuromuscular end-plate by dehydration
C. is important in the stimulation of pancreatic function
D. is the neurotransmitter involved in vagal stimulation of the heart
E. is antagonised by neostigmine
Answer: C.is important in the stimulation of pancreatic function
504. The functions of tropomyosin in skeletal muscle include:
A. releasing Ca2+ after an action potential
B. sliding on actin to produce shortening
C. binding to myosin during contraction
D. acting as a “releasing protein” at rest by covering up the sites where myosin binds to actin
E. generating ATP which passes to the contractile mechanism
Answer: D.acting as a “releasing protein” at rest by covering up the sites where myosin binds to actin
505. Membrane potential:
A. is only found in nervous tissue
B. is not contributed to by the Na+ /K+ pump
C. magnitude does not change from tissue to tissue
D. is negative inside in relation to the outside
E. is mainly caused by leaking Na+ / K+ channels
Answer: D.is negative inside in relation to the outside
506. Gamma amino butyric acid:
A. is an excitatory mediator in the brain
B. is formed by decarboxylation of glutamate
C. acts at three different classes of GABA receptors
D. is mostly secreted unchanged in the urine
E. is the main mediator in glutamate
Answer: B.is formed by decarboxylation of glutamate
507. Substance P:
A. is a carbohydrate
B. is a polypeptide found in the intestine and nervous tissue
C. is a β II amino acid residue mainly found in the liver
D. is not involved in the neuroendocrine system
E. is a lipid
Answer: B.is a polypeptide found in the intestine and nervous tissue
508. Opioid peptides:
A. are not formed from precursors
B. include morphine as an example
C. form the opioid receptors in the brain
D. are mainly found in the brain and gastrointestinal tract
E. are almost always excreted unchanged
Answer: D.are mainly found in the brain and gastrointestinal tract
509. Regarding the autonomic nervous system:
A. does not have a reflex arc like somatic nervous system
B. has dopamine as the main transmitter
C. has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion
D. neurotransmitter noradrenaline is metabolised by pseudocholinesterase
E. is not involved with visceral sensation
Answer: C.has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion
510. Contraction of skeletal muscle is initiated by Ca++ binding to:
A. tropomyosin
B. myosin
C. actin
D. troponin C
E. troponin I
Answer: D.troponin C
511. The stretch reflex in skeletal muscle:
A. is a feedback reflex aimed at maintaining muscle length
B. is a polysynaptic reflex
C. maintains muscle strength at various levels of muscle strength
D. is not elicited in the knee jerk which occurs after tapping
E. none of the above are true
Answer: A.is a feedback reflex aimed at maintaining muscle length
512. Excitary amino acids in the brain are:
A. glutamate and GABA
B. GABA and glycine
C. glutamate and glycine
D. glycine and aspartate
E. glutamate and aspartate
Answer: E.glutamate and aspartate
513. The opioid δ receptor is involved in:
A. analgesia
B. respiratory depression
C. miosis
D. dependence
E. all of the above
Answer: A.analgesia
514. With regard to contraction and relaxation of skeletal muscle, all of the following aretrue EXCEPT:
A. contraction involves the release of K+ from the terminal cisterns
B. relaxation involves the release of Ca2+ from troponin
C. prior to contraction, increase Na+ and K+ conduction occurs in the end-plate membrane
D. relaxation involves cessation of the interaction between actin and myosin
E. contraction involves inward spread of depolarisation along T tubules
Answer: A.contraction involves the release of K+ from the terminal cisterns
515. Regarding nerve fibres:
A. type C myelinated fibres in the dorsal root conduct impulses concerning pain and temperature
B. type A α unmyelinated fibres conduct impulses concerning proprioception
C. type A β unmyelinated fibres conduct impulses concerning light touch
D. type A γ unmyelinated fibres conduct impulses to muscle spindles
E. type B myelinated fibres are located in preganglionic autonomic region
Answer: E.type B myelinated fibres are located in preganglionic autonomic region
516. With regard to chemoreceptors, all of the following are true EXCEPT:
A. the medullary chemoreceptors respond to a change in blood pCO2
B. the medullary chemoreceptors respond to blood (H+)
C. the predominant peripheral chemoreceptors are located in the carotid and aortic bodies
D. the peripheral chemoreceptors respond to pO2
E. the peripheral chemoreceptors respond to blood (H+)
Answer: B.the medullary chemoreceptors respond to blood (H+)
517. In the autonomic nerve system, β antagonism results in:
A. constriction of the renal vasculature
B. decreased velocity of conduction in the atrioventricular node
C. decreased velocity of conduction in the HIS/Purkinje system
D. decreased ventricular contractility
E. increased insulin and glucagon secretion
Answer: E.increased insulin and glucagon secretion
518. The reticular activating system:
A. has depressed conduction during anaesthesia
B. is located in the pons
C. is a simple collection of parallel nerve fibres
D. has no input from the cranial nerves
E. is electrically isolated from the cerebral cortex
Answer: A.has depressed conduction during anaesthesia
chapter:
Renal
519. Which substance is 60 times more concentrated in urine than in plasma?
A. glucose
B. creatinine
C. sodium
D. urea
Answer: D.urea
520. Regarding the anatomy of the kidney:
A. the afferent arteriole is smaller than the efferent
B. the kidney contains 1.3 million nephrons
C. there are three layers separating the blood in the arteriole from the glomerular filtrate
D. podocytes are contractile and regulate GFR
Answer: B.the kidney contains 1.3 million nephrons
521. Regarding the glomerulus filtration fx:
A. it allows passage of molecules up to 4nm diameter freely, and up to 8nm with some difficulty depending on charge
B. positively charged molecules pass more easily than neutral
C. endothelial pores have a greater diameter than podocyte filtration slits
D. the basal lamina contains interruptions
Answer: A.it allows passage of molecules up to 4nm diameter freely, and up to 8nm with some difficulty depending on charge
522. The renal tubule:
A. all sections are lined with cuboidal epithelial cells with luminal microvilli
B. the thick loop of Henle rises to lie adjacent to its glomerulus
C. there are a greater number of juxtamedullary nephrons than cortical
D. the lacis cells of the juxtaglomerular apparatus secrete renin
Answer: B.the thick loop of Henle rises to lie adjacent to its glomerulus
523. Regarding glomerular blood supply:
A. the efferent arterioles are branches of the interlobular arterioles
B. the descending vasa recta vessels contain fenestrated endothelium to assist urea transport
C. the efferent arterioles empties into the peritubular network
D. the glomerular capillaries drain into the efferent vein
Answer: C.the efferent arterioles empties into the peritubular network
524. If [urine]PAH = 14mg/ml, urine flow = 0.9ml/min and [plasma]PAH = 0.02mg/ml
i) What is the clearance of PAH?
ii) If the extraction ratio of PAH is 0.9, what is the renal blood flow (Hct=45%)?
A. ClPAH = 630, renal blood flow = 1273ml/min
B. ClPAH = 630, renal blood flow = 700mb/min
C. ClPAH = 77, renal blood flow = 155mb/min
D. ClPAH = 777mb/min, renal blood flow = 1569mb/min
Answer: A.ClPAH = 630, renal blood flow = 1273ml/min
525. Renal blood pressure:
A. the pressure drop across the glomerulus is about 20mmHg
B. pressure in the renal vein is about 15mmHg
C. the glomerular capillary pressure is about 80% that of arterial
D. the greatest drop in pressure (percentage wise) is from the efferent arteriole to the peritubular capillary
Answer: D.the greatest drop in pressure (percentage wise) is from the efferent arteriole to the peritubular capillary
526. Regarding renal innervation:
A. transplanted kidneys initially have reduced concentrating ability because of lack of innervation of the juxtaglomerular cells and therefore decreased renin secretion
B. norepinephrine acts directly on α receptors on the juxtaglomerular cells
C. renal blood flow increases during exercise
D. autoregulation of renal blood flow can be disrupted by angiotensin-II inhibitors when renal perfusion is low
Answer: D.autoregulation of renal blood flow can be disrupted by angiotensin-II inhibitors when renal perfusion is low
527. The glomerular filtration rate:
A. is usually in the order of 125mL/min for an average healthy male
B. is equal to the clearance of creatinine
C. is indirectly related to filtration coefficient
D. is determined by [urine]inulin
Answer: A.is usually in the order of 125mL/min for an average healthy male
528. Which of the following will cause an increase in GFR?
A. dehydration
B. ureteral obstruction
C. afferent arteriole constriction
D. hypoproteinaemia
Answer: D.hypoproteinaemia
529. Na+ resorption does not occur in which part of the nephron?
A. proximal convoluted tubule
B. thin descending loop of Henle
C. thick ascending loop of Henle
D. distal convoluted tubule
E. collecting duct
Answer: B.thin descending loop of Henle
530. Which is NOT resorbed via cotransport with Na+ in the PCT?
A. lactate
B. phosphate
C. hydrogen
D. amino acids
E. collecting duct
Answer: C.hydrogen
531. Fanconi’s syndrome of decreased levels of ATP in the tubular epithelium of the PCT:
A. decreases Na+ extrusion from the cell into the interstitium
B. causes increased phosphate absorption
C. causes metabolic alkalosis
D. results in decreased amino acid excretion
E. collecting duct
Answer: A.decreases Na+ extrusion from the cell into the interstitium
532. Anti-diuretic hormone controls the concentration of urine,
A. and can concentrate urine to up to 2500mosm/kg H??? H2O
B. in its absence, the collecting duct is impermeable to water
C. causing the ultimate resorption of up to 99.7% of the filtrate
D. by causing upregulation of aquaporin-1 channels
E. collecting duct
Answer: C.causing the ultimate resorption of up to 99.7% of the filtrate
533. Regarding H+ renal excretion:
A. the distal convoluted tubule brush border contains carbonic anhydrase
B. H+ secretion occurs in all segments of the nephrons
C. H+ + NH3 →NH4+ is the most significant tubular buffering reaction
D. CO2 is recycled / resorbed in the PCT to allow enhanced acid secretion
E. collecting duct
Answer: D.CO2 is recycled / resorbed in the PCT to allow enhanced acid secretion
534. In the nervous control of the bladder which nerves do NOT play a role in micturition?
A. sympathetic nerves from L2 in hypogastric nerve
B. somatic motor neurons in pudendal nerve
C. sensory neurons to S2/3 in pelvic nerves
D. parasympathetic supply in pelvic nerves
E. collecting duct
Answer: A.sympathetic nerves from L2 in hypogastric nerve
535. Which is the least significant buffering system in the blood?
A. H+ + plasma protein HProt
B. H+ +HPO4 2- H2PO4-
C. H+ + HCO3 – H2CO3
D. H+ + Hb HHb
E. collecting duct
Answer: B.H+ +HPO4 2- H2PO4-
536. In which body compartment is the bicarb buffering system least important?
A. intracellular
B. interstitial
C. CSF
D. blood
E. collecting duct
Answer: A.intracellular
537. In which state is extracellular buffering more important than intracellular?
A. respiratory acidosis
B. respiratory alkalosis
C. metabolic acidosis
D. metabolic alkalosis
E. collecting duct
Answer: D.metabolic alkalosis
538. Renal acid secretion is enhanced by:
A. respiratory acidosis
B. respiratory alkalosis
C. hyperkalaemia
D. carbonic anhydrase inhibition
E. collecting duct
Answer: A.respiratory acidosis
539. Carbonic anhydrase is not inhibited by:
A. cyanide
B. zinc
C. azide
D. sulphide
E. collecting duct
Answer: B.zinc
540. What increases GFR:
A. moderate constriction of efferent arterioles
B. moderate constriction of afferent arterioles
C. increased Bowman’s capsule pressure
D. increased glomerular capillary osmotic pressure
E. collecting duct
Answer: A.moderate constriction of efferent arterioles
541. What increases the anion gap:
A. increased concentration of Mg2+
B. decreased concentration of plasma proteins
C. decreased concentration of lactate
D. increased concentration of ketoacids
E. collecting duct
Answer: D.increased concentration of ketoacids
542. Which is CORRECT?
A. humans have approximately 1.3 million nephrons
B. glomerular membrane excludes substances greater than 4nm in diameter
C. total area of glomerular capillary endothelium is 8m2
D. nephrons length is 45-65mm
E. collecting duct
Answer: D.nephrons length is 45-65mm
543. Which of the following is TRUE?
A. U/P ratio for creatinine is 150mg/dl
B. U/P ratio for glucose is 10
C. Na concentration in the urine usually exceeds over 150mg/dl
D. the usual glucose excretion in the urine is 100mg/dl
E. collecting duct
Answer: A.U/P ratio for creatinine is 150mg/dl
544. Which of the following is FALSE?
A. proximal convoluted tubular cells have lateral intercellular spaces
B. the cells in the descending loop of Henle have large numbers of mitochondria
C. the ascending loop of Henle contributes to the formation of juxtaglomerular apparatus
D. in humans only 15% of the nephrons have long loops
E. collecting duct
Answer: B.the cells in the descending loop of Henle have large numbers of mitochondria
545. Regarding tubular function:
A. 90% of the water is absorbed by the proximal convoluted tubule
B. renal threshold for glucose is 300mg/dl
C. the main mechanism of the Na reabsorption from the tubular fluid to proximal convoluted tubule is via Na/K/ATP a pump
D. the main mechanism of Na absorption in the ascending loop of Henle is via cotransport of Na/K/2Cl:
E. collecting duct
Answer: D.the main mechanism of Na absorption in the ascending loop of Henle is via cotransport of Na/K/2Cl:
546. The maximum effect of vasopressin occurs at:
A. distal convoluted tubule
B. proximal convoluted tubule
C. cortical part of the collecting duct
D. medullary part of collecting duct
E. thick ascending limb of loop of Henle
Answer: C.cortical part of the collecting duct
547. Regarding the buffer system in the tubular fluid, which one is TRUE?
A. the main buffer system is H2PO4
B. the main mechanism of H+ secretion in the proximal tubule is via proton pump
C. dibasic phosphate buffer is most effective at proximal convoluted tubule
D. the H+ secretion at proximal tubule is mediated Na/K/ATPase
E. thick ascending limb of loop of Henle
Answer: D.the H+ secretion at proximal tubule is mediated Na/K/ATPase
548. Regarding the renin-angiotensin system, which is CORRECT?
A. renin has many functions including the formation of angiotensin I from angiotensinogen
B. after nephrectomy, circulating levels of prorenin fall
C. renin is formed in the juxtaglomerular cells of the kidney
D. active renin has a half-life in the circulation of 40 minutes or less
E. prorenin is biologically active
Answer: C.renin is formed in the juxtaglomerular cells of the kidney
549. All of the following increase renin secretion EXCEPT:
A. sodium depletion
B. diuretics
C. hypertension
D. cardiac failure
E. cirrhosis
Answer: C.hypertension
550. All of the following factors inhibit renin secretion EXCEPT:
A. prostaglandins
B. angiotensin II
C. vasopressin
D. increased afferent arteriolar pressure
E. increased Na+ and Cl- reabsorption across the macular densa
Answer: A.prostaglandins
551. Which of the following blood gas results is consistent with a three-week residence at 4000m altitude, after previously living at sea-level? pH HCO3 – (meq/L) pCO2
A. 7.40 24.1 40
B. 7.50 30.1 40
C. 6.96 5.0 23
D. 7.34 33.5 64
E. 7.48 18.7 26
Answer: E.7.48 18.7 26
552. In a resting adult, the kidneys receive how much of the cardiac output?
A. 15%
B. 20%
C. 25%
D. 30%
E. 35%
Answer: C.25%
553. Which of the following is INCORRECT regarding regulation of renal blood flow?
A. noradrenaline constricts the renal vessels
B. dopamine causes renal vasodilation and natriuresis
C. angiotensin II exerts a constrictor effect on the efferent arterioles
D. prostaglandins increase blood flow in the renal cortex and decrease blood flow in the renal medulla
E. acetylcholine produces renal vasoconstriction
Answer: E.acetylcholine produces renal vasoconstriction
554. Erythropoietin:
A. is produced in the juxtaglomerular cells of the kidney
B. production is stimulated by theophylline
C. secretion is facilitated by the acidosis that develops at high altitude
D. has a half-life in the circulation of about 5 hours
E. is produced predominantly in the spleen in neonates
Answer: D.has a half-life in the circulation of about 5 hours
555. Mesengial cell contraction is stimulated by:
A. ANP
B. dopamine
C. PGE2
D. cAMP
E. angiotensin II
Answer: E.angiotensin II
556. Ethanol’s action as a diuretic occurs by:
A. inhibition of vasopressin secretion
B. inhibition of the action of vasopressin on the collecting duct
C. production of an osmotic diuresis
D. decreasing tubular reabsorption of Na and increasing GFR
E. inhibition of the Na+ -K+ -Cl- cotransporter in the medullary thick ascending limb of the loop of Henle
Answer: B.inhibition of the action of vasopressin on the collecting duct
557. With regard to diuretics:
A. frusemide acts on the thick ascending limb of the loop of Henle
B. antagonists to V2 vasopressin receptors act on the early portion of the distal convoluted tubule
C. thiazides act primarily on the thick ascending limb of the loop of Henle
D. loop diuretics act on the collecting ducts
E. aldosterone antagonists act on the early portion of the distal convoluted tubule
Answer: A.frusemide acts on the thick ascending limb of the loop of Henle
558. In the presence of vasopressin, most filtered water is absorbed in the?
A. proximal tubule
B. loop of Henle
C. distal tubule
D. cortical collecting system
E. medullary collecting system
Answer: A.proximal tubule
559. Which pattern of laboratory findings in the tale below is most consistent with a diagnosis of diabetes insipidis? 24 Hr Urine Vol Ketones Glucose Protein
A. 4.0 + 0 0
B. 6.2 2+ 4+ 0
C. 1.6 0 0 4+
D. 6.4 0 0 0
E. 5.0 0 0 3+
Answer: D.6.4 0 0 0
560. On which of the following does aldosterone exert its greatest effect?
A. glomerulus
B. proximal tubule
C. thin portion of loop of Henle
D. thick portion of look of Henle
E. cortical collecting system
Answer: E.cortical collecting system
561. What is the clearance of a substance when its concentration in plasma is 1mg/ml, itsconcentration in urine is 10mg/ml and the urine flow is 2ml/min?
A. 2ml/min
B. 10ml/min
C. 20ml/min
D. 200ml/min
E. clearance cannot be determined from the information given
Answer: C.20ml/min
562. Glucose reabsorption occurs in the:
A. proximal tubule
B. loop of Henle
C. distal tubule
D. cortical collecting system
E. medullary collecting system
Answer: A.proximal tubule
563. As urine flow increases during osmotic diuresis:
A. the osmolality of urine falls
B. the osmolality of urine increases
C. the osmolality of urine approaches that of plasma
D. the osmolality of urine is unchanged
E. the osmolality of urine depends primarily on other factors
Answer: C.the osmolality of urine approaches that of plasma
564. Which of the following is NOT true regarding the voiding reflex?
A. it involves parasympathetic fibres
B. it remains intact in the period of spinal shock following transaction of the spinalcord
C. it occurs when the bladder volume reaches 300-400mls
D. it is integrated in the sacral segments of the spinal cord
E. its threshold is altered by inhibitory fibres from the brainstem
Answer: B.it remains intact in the period of spinal shock following transaction of the spinalcord
565. Which of the following substances is NOT actively secreted in to the tubular lumen by the proximal renal tubule?
A. urate
B. para-amino hippuric acid
C. catecholamines
D. sodium
E. creatinine
Answer: D.sodium
566. Angiotensin II causes:
A. greater constriction of efferent than afferent arterioles
B. greater construction of afferent than efferent arterioles
C. constriction of afferent arterioles only
D. constriction of efferent arterioles only
E. has no effect on arteriolar constriction
Answer: A.greater constriction of efferent than afferent arterioles
567. With regard to the effect of hormones on renal tubules, which is CORRECT?
A. aldosterone increases potassium reabsorption from the distal tubule
B. angiotensin II increases hydrogen ion secretion from the proximal tubules
C. ADH increases water reabsorption in the proximal tubule
D. atrial naturetic peptide decreases sodium reabsorption from the proximal tubules
E. parathyroid hormone increases phosphate reabsorption
Answer: B.angiotensin II increases hydrogen ion secretion from the proximal tubules
568. With regard to tuboglomerular feedback:
A. the GFR increases when flow through the distal tubule increases
B. the macula densa on the afferent arteriole is the sensor
C. the afferent arteriole is constricted by thromboxane A2
D. it is designed to maintain sodium reabsorption
E. it does not operate in individual nephrons
Answer: C.the afferent arteriole is constricted by thromboxane A2
569. The primary reason for the decreased medullary hypertonicity associated withosmotic diuresis is:
A. an associated increased urine volume
B. the limiting concentration gradient for sodium reabsorption is reached
C. tubular fluid has an increased sodium concentration
D. the total amount of sodium reaching the loop of Henle is increased
E. the associated maximal vasopressin secretion
Answer: B.the limiting concentration gradient for sodium reabsorption is reached
570. With respect to renal handling of glucose:
A. glucose is reabsorbed from within the distal tubule by co-transport
B. glucose is reabsorbed from within the proximal tubule by facilitated diffusion
C. glucose is always completely reabsorbed
D. movement of glucose from tubular epithelial cells is by passive diffusion
E. none of the above
Answer: E.none of the above
571. Creatinine:
A. is synthesised in the liver from methionine, glycine and anganine
B. is converted directly to creatine
C. has variable excretion from day to day
D. creatinuria occurs normally in the elderly and in pregnant women
E. all of the above
Answer: D.creatinuria occurs normally in the elderly and in pregnant women
572. The thin ascending loop of Henle is:
A. relatively permeable to water
B. relatively impermeable to sodium ion
C. permeable to both water and sodium ion
D. relatively impermeable to water
E. relatively impermeable to both water and sodium ion
Answer: D.relatively impermeable to water
573. The primary effect of angiotensin II on renal vasculature is:
A. constriction of efferent arterioles
B. enhanced prostaglandin mediated increased blood flow to the renal cortex
C. enhanced catecholamine mediated afferent arteriolar vasoconstriction
D. enhanced catecholamine mediated afferent vasodilatation
E. constriction of interlobular arteries
Answer: A.constriction of efferent arterioles
574. What percentage of filtered sodium is reabsorbed by the kidney?
A. 1%
B. 93%
C. 99%
D. 50%
E. 100%
Answer: C.99%
575. Tuboglomerular feedback refers to:
A. the process of increased sodium reabsorption associated with an increased glomerular filtration
B. changes in peri-tubular oncotic pressure associated with changes in glomerular filtration
C. decreased glomerular filtration associated with increased flow through the loop of Henle
D. increased glomerular filtration associated with decreased peri-tubular oncotic pressure
E. thromboxane A2 mediated increased sodium reabsorption associated with increased renal blood flow
Answer: C.decreased glomerular filtration associated with increased flow through the loop of Henle
576. Frusemide acts mainly at:
A. proximal tubule
B. thin limb of loop of Henle
C. thick limb of loop of Henle
D. distal tubule
E. collecting duct
Answer: C.thick limb of loop of Henle
577. At which site does tubular fluid osmolality exceed that of plasma by the greatestamount?
A. proximal tubule
B. thin limb of loop of Henle
C. thick limb of loop of Henle
D. distal tubule
E. collecting duct
Answer: B.thin limb of loop of Henle
578. At which site is sodium ion NOT actively reabsorbed?
A. proximal tubule
B. thin limb of loop of Henle
C. thick limb of loop of Henle
D. distal tubule
E. collecting duct
Answer: B.thin limb of loop of Henle
579. At which site(s) is potassium ion secreted?
A. distal tubule and collecting duct
B. proximal tubule and distal tubule
C. think limb of loop of Henle only
D. thin limb and thick limb of loop of Henle
E. none of the above
Answer: A.distal tubule and collecting duct
580. At which site does chlorthiazide act?
A. proximal tubule
B. thin limb of loop of Henle
C. thick limb of loop of Henle
D. distal tubule
E. collecting duct
Answer: D.distal tubule
581. The cortical portion of the collecting duct has the capacity to reabsorb approximately 10% of the filtered water. Which substance is most important in regulating this effect?
A. angiotensin II
B. histamine
C. vasopressin
D. sodium
E. prostaglandins
Answer: C.vasopressin
582. With respect to GFR:
A. clearance of p-amino hippuric acid is used to determine GFR
B. inulin cannot be used to measure GFR
C. GFR is usually reduced in ureteric obstruction
D. filtration pressure changes with change in blood pressure
E. contraction of mesangial cells increases GFR
Answer: C.GFR is usually reduced in ureteric obstruction
583. With respect to the loop of Henle:
A. the ascending limb is highly permeable to water
B. the descending limb is impermeable to water
C. the thick ascending limb co-transports sodium, potassium and chloride out of the lumen
D. tubular fluid becomes concentrated as it passes through the ascending limb
E. the ascending limb removes approximately 15% of filtered water
Answer: C.the thick ascending limb co-transports sodium, potassium and chloride out of the lumen
584. Mesangial cells:
A. are specialised cells that are characterised by numerous pseudopodia
B. are made to contract by dopamine
C. are made to contract by angiotensin II
D. lie within the renal medulla
E. decrease the area for filtration when they relax
Answer: C.are made to contract by angiotensin II
585. Regarding the proximal tubule, the following statements are true EXCEPT:
A. sodium is co-transported out of the tubule with glucose
B. sodium is actively transported into the intercellular spaces by Na-K-ATPase
C. the cells are characterised by a brush border and tight junctions
D. vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane
E. water moves passively out of the tubule along osmotic gradients
Answer: D.vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane
586. Renal autoregulation of GFR helps prevent large fluctuations in GFR despite wide variations in arterial blood pressure. With regard to autoregulation, which is TRUE?
A. the macula densa cells sense change in afferent arteriolar pressure
B. falling GFR results in a feedback to decrease efferent arteriolar pressure
C. falling GFR results in an increase in renin secretion from macula densa cells
D. decreased macula densa concentration of NaCl results in dilatation of afferent arterioles
E. decreased GFR decreases NaCl reabsorption in the ascending loop of Henle
Answer: D.decreased macula densa concentration of NaCl results in dilatation of afferent arterioles
587. Aldosterone has its principle effect in the:
A. proximal convoluted tubule
B. descending loop of Henle
C. thick ascending loop of Henle
D. distal convoluted tubule
E. collecting ducts
Answer: E.collecting ducts
588. 85% of NaHCO3 in the filtrate is reabsorbed in the:
A. proximal convoluted tubule
B. descending loop of Henle
C. thick ascending loop of Henle
D. distal convoluted tubule
E. collecting ducts
Answer: A.proximal convoluted tubule
589. Thiazide diuretics exert their main effect in the:
A. proximal convoluted tubule
B. descending loop of Henle
C. thick ascending loop of Henle
D. distal convoluted tubule
E. collecting ducts
Answer: D.distal convoluted tubule
590. Ethacrynic acid exerts its principle effect in the:
A. proximal convoluted tubule
B. descending loop of Henle
C. thick ascending loop of Henle
D. distal convoluted tubule
E. collecting ducts
Answer: C.thick ascending loop of Henle
591. When considering fluid balance, which of the following is INCORRECT?
A. the minimum daily fluid output may normally be estimated by measuring the urine output and adding 500ml
B. urine output is always the single largest contributor to fluid output
C. fluid intake and output may be altered in response to a change in extracellular osmolarity
D. fluid intake and output may be altered in response to a change in extracellular volume
E. the hypothalamus is an important regulator of fluid intake
Answer: B.urine output is always the single largest contributor to fluid output
592. Which of the following does NOT stimulate erythropoietin secretion?
A. cobalt salts
B. thromboxanes
C. androgens
D. adenosine
E. prostaglandins
Answer: B.thromboxanes
593. Glomerular filtration rate is best measured using:
A. inulin
B. glucose
C. PAH
D. urea
E. creatinine
Answer: A.inulin
594. “Renal dose” dopamine increases glomerular filtration rate by:
A. dilating the renal arteries
B. dilating the vasa recta
C. constricting the efferent arteriole
D. relaxing glomerular perivascular mesangial cells
E. all of the above
Answer: D.relaxing glomerular perivascular mesangial cells
595. Regarding the kidney:
A. the glomerular filtration rate is 125mls/hr
B. the renal threshold for glucose 300mg/dL
C. glucose transport is an example of secondary active transport
D. the blood flow in the renal medulla is greater than in renal cortex
E. a high protein diet decreases renal blood flow
Answer: C.glucose transport is an example of secondary active transport
596. Which of the following substances is not excreted by the kidney in a normal adult on an average diet?
A. K+
B. uric acid
C. creatinine
D. glucose
E. urea
Answer: D.glucose
597. Which of the following statements regarding erythropoietin is INCORRECT in an adult?
A. half-life of about 5 hours
B. hypoxia can increase secretion within minutes
C. is secreted by spleen and salivary glands
D. is secreted in adequate amounts by liver in absence of kidneys
E. is a glycoprotein
Answer: D.is secreted in adequate amounts by liver in absence of kidneys
598. “Renal dose” dopamine is:
A. 1-2 mcg/kg/min
B. 1-5 mcg/kg/min
C. 1-10 mcg/kg/min
D. 1-20 mcg/kg/min
E. greater than 20 mcg/kg/min
Answer: D.1-20 mcg/kg/min
599. Frusemide acts as a diuretic primarily by:
A. inhibiting Na+ /K+ /Cl- co-transport in loop of Henle
B. inhibiting action of vasopressin on collecting duct
C. decreasing H+ secretion with resultant increase in Na+/K+ excretion
D. inhibiting vasopressin secretion
E. inhibiting Na+/K+ exchange in collecting ducts by inhibiting the action of aldosterone
Answer: A.inhibiting Na+ /K+ /Cl- co-transport in loop of Henle
600. Regarding the osmolality of renal tubular fluid, is it?
A. hypotonic in loop of Henle
B. isotonic in proximal tubule
C. hypertonic in distal tubule
D. hypotonic in collecting duct
E. hypotonic in proximal tubule
Answer: B.isotonic in proximal tubule
601. Which of the following statements regarding renal tubular glucose absorption isINCORRECT?
A. binds to SGLT-2 in luminal membrane
B. example of secondary active transport
C. transported out of luminal cell by GLUT-2
D. about 100% reabsorption in proximal tubule if less than transport maximum
E. linked to sodium reabsorption
Answer: A.binds to SGLT-2 in luminal membrane
602. Which of the following does NOT increase renal tubular sodium reabsorption?
A. cortisol
B. oestrogen
C. growth hormone
D. insulin
E. glucagon
Answer: E.glucagon
603. Regarding renal handling of glucose, which is INCORRECT?
A. transport maximum varies depending on sex
B. proximal tubular absorption is an example of a symport mechanism
C. not all nephrons handle glucose filtration and reabsorption equally
D. phlorhizin inhibits distal tubular reabsorption
E. GLUT-2 transports glucose into interstitial fluid
Answer: D.phlorhizin inhibits distal tubular reabsorption
604. Regarding renal handling of sodium, which is INCORRECT?
A. more than 95% of filtered sodium is reabsorbed
B. proximal tubular reabsorption is an example of secondary active transport
C. aldosterone increases reabsorption despite increasing GFR
D. glucocorticoids may increase or decrease urinary excretion
E. renal oxygen consumption is directly proportional to sodium reabsorption
Answer: C.aldosterone increases reabsorption despite increasing GFR
605. Which of the following agents cause relaxation of mesangial cells of the glomerulus?
A. angiotensin II
B. dopamine
C. endothelins
D. vasopressin
E. noradrenaline
Answer: B.dopamine
606. Regarding renal handling of bicarbonate ion, which is INCORRECT?
A. small size of bicarbonate ion affects reabsorption
B. reabsorption is reciprocally related to chloride ion reabsorption in proximal tubule
C. most reabsorption occurs in proximal tubule
D. reabsorption requires carbonic anhydrase
E. reabsorption is decreased by ECF expansion
Answer: A.small size of bicarbonate ion affects reabsorption
607. Regarding renal handling of ammonia, which is INCORRECT?
A. ammonia is not filtered at the glomerulus
B. ammonia is synthesised in proximal and distal tubules
C. glutaminase plays a role in ammonia excretion
D. non-ionic diffusion of ammonia maintains a concentration gradient for further diffusion
E. ammonia diffusion can increase up to 30 fold
Answer: E.ammonia diffusion can increase up to 30 fold
608. Regarding renal handling of calcium, which is INCORRECT?
A. metabolic acidosis decreases reabsorption
B. growth hormone increases reabsorption
C. calcium is actively reabsorbed
D. about 60% of filtered calcium load is reabsorbed in proximal tubules
E. glucocorticoids increase calcium reabsorption
Answer: B.growth hormone increases reabsorption
609. Regarding renal handling of chloride, which is INCORRECT?
A. about 25% of filtered load is actively reabsorbed in thick ascending limb
B. proximal tubular reabsorption is reciprocally related to bicarbonate reabsorption
C. it is actively secreted in distal tubule
D. two chloride per sodium are reabsorbed in thick ascending limb
E. chloride-hydroxide antiport are present in the kidney
Answer: C.it is actively secreted in distal tubule
610. Regarding glomerular filtration:
A. the glomerular filtration rate varies les than the renal plasma flow
B. inulin is stored in the kidney
C. sialoproteins in the glomerular capillary wall are positively charged
D. dopamine causes contraction of mesangial cells
E. changes in renal blood flow do not affect glomerular filtration rate
Answer: A.the glomerular filtration rate varies les than the renal plasma flow
611. Regarding renal handling of phosphate, which is INCORRECT?
A. no tubular secretion occurs
B. most reabsorption occurs actively in proximal tubule
C. parathyroid hormone inhibits tubular reabsorption
D. less than 5% of filtered load is excreted
E. phosphate is a much more powerful buffer in tubular fluid than in blood
Answer: D.less than 5% of filtered load is excreted
612. Regarding renal handling of hydrogen ion, which is INCORRECT?
A. acetazolamide decreases tubular secretion
B. aldosterone increases distal tubular secretion
C. much more acid secretion occurs in proximal than distal tubule
D. lowest tubular fluid pH achievable is 4.5
E. secondary active transport mechanism operates in distal tubule
Answer: E.secondary active transport mechanism operates in distal tubule
613. In diabetes insipidis:
A. percentage of filtered water reabsorbed is increased compared to normal
B. there is a net gain of water in excess of solute (L/day)
C. urine volume (L/day) is decreased
D. urine concentration (msom/L) is markedly reduced
E. glomerular flow (ml/min) is increased
Answer: D.urine concentration (msom/L) is markedly reduced
614. Which site of diuretic action is INCORRECT?
A. antidiuretic hormone antagonists act in collecting duct
B. loop agents act in thin ascending limb
C. carbonic anhydrase inhibitors act in proximal tubule
D. thiazides act in early distal tubule
E. aldosterone antagonists act in cortical collecting tubule
Answer: B.loop agents act in thin ascending limb
615. Which of the following statements regarding angiotensin is INCORRECT?
A. angiotensin II has a half-life of about 1-2 minutes
B. angiotensin I is physiologically inactive
C. angiotensin III has equivalent pressor activity to angiotensin II
D. angiotensinogen mainly comes from the liver
E. angiotensin converting enzyme is a dipeptidyl carboxypeptidase angiotensin converting enzyme
Answer: C.angiotensin III has equivalent pressor activity to angiotensin II
616. Regarding renal tubular function:
A. Na+ is actively transported out of the thin portions of the loop of Henle
B. Na+ -K+ ATPase pumps Na+ out of the renal tubule
C. Cl- is transported only by co-transport
D. glucose is reabsorbed mainly in the distal tubule
E. penicillin is not actively secreted into tubular fluid
Answer: B.Na+ -K+ ATPase pumps Na+ out of the renal tubule
617. Regarding the actions of angiotensin II, which is INCORRECT?
A. selective renal efferent arteriolar constriction
B. acts on CNS without crossing blood-brain barrier
C. contract mesangial cells
D. direct positive chronotropic action on heart
E. increases conversion of cholesterol to pregnenelone
Answer: D.direct positive chronotropic action on heart
618. Normal values for renal function include all of the following EXCEPT:
A. filtration fraction =0.2
B. 22% of cardiac output
C. GFR = 180 litres/day
D. RPF = 900 litres/day
E. Tm glucose = 450 mg/minute
Answer: E.Tm glucose = 450 mg/minute
619. Regarding renal handling of potassium, which is INCORRECT?
A. 10 to 15% of filtered load may be excreted in urine
B. two potassium per sodium are reabsorbed in thick ascending limb
C. excretion decreased in acidosis
D. distal tubular secretion is capable of “adaptation” depending on demand
E. aldosterone increases distal tubular secretion in exchange for sodium
Answer: B.two potassium per sodium are reabsorbed in thick ascending limb
620. Normal urinary values include all of the following EXCEPT:
A. albumin ≤ 150mg/day
B. pH = 4.5 to 8.0
C. volume = 0.5 to 2.4 litres/day
D. specific gravity = 1.010 to 1.035
E. osmolality = 3 to 1400 millismol/litres
Answer: A.albumin ≤ 150mg/day
621. Regarding the kidney:
A. prostaglandins decrease blood flow in renal cortex
B. acetylcholine produces renal vasoconstriction
C. angiotensin II causes constriction of efferent arterioles
D. angiotensin II causes constriction of afferent arterioles
E. glomerular capillary pressure normally is about 100mmHg
Answer: C.angiotensin II causes constriction of efferent arterioles
622. Glucose reabsorption is most marked in which segment of the glomerulus?
A. the proximal convoluted tubule
B. the distal convoluted tubule
C. the descending loop of Henle
D. the ascending loop of Henle
E. the collecting system
Answer: A.the proximal convoluted tubule
623. Why is NSAIDs use a relative contraindication in patients with chronic renal failure?
A. direct toxic effects on proximal tubule
B. direct toxic effects on collecting ducts
C. indirect toxic effects on loop of Henle
D. inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in arterioles
E. inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in main renal arteries
Answer: D.inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in arterioles
624. Characteristics of a substance suitable for measuring GFR do NOT include:
A. freely filtered
B. not toxic
C. no effect on filtration rate
D. not metabolised
E. of low molecular weight
Answer: E.of low molecular weight
625. Amino acid reabsorption is most marked in which segment of the glomerulus?
A. the proximal convoluted tubule
B. the distal convoluted tubule
C. the descending loop of Henle
D. the ascending loop of Henle
E. the collecting duct
Answer: A.the proximal convoluted tubule
626. Which of the following substances would NOT cause contraction of mesangial cells?
A. angiotensin II
B. dopamine
C. vasopressin
D. histamine
E. platelet activating factor
Answer: B.dopamine
627. Chloride may be reabsorbed in the nephron by:
A. passive reabsorption
B. active co-transport with K+ and Na+
C. OH- /Cl- antiport
D. all of the above
E. none of the above
Answer: D.all of the above
628. Which of these factors do NOT affect GFR?
A. renal blood flow
B. ureteral obstruction
C. dehydration
D. a neutral molecule measuring 4 manometer
E. angiotensin II effects on mesangial cells
Answer: D.a neutral molecule measuring 4 manometer
629. The collecting duct is the main site of action for which of the following drugs?
A. ethanol
B. demeclocycline
C. thiazide diuretics
D. ethacrynic acid
E. caffeine
Answer: B.demeclocycline
630. Which is NOT true of osmotic diuresis?
A. osmotic diuresis is due to the quantity of unreabsorbed solutes
B. decreased water reabsorption in proximal tubules and loops
C. reduced Na+ reabsorption as the limiting concentration gradient is exceeded
D. net loss of Na+ in urine
E. normal water reabsorption in proximal portion of tubules
Answer: E.normal water reabsorption in proximal portion of tubules
631. Which of these is NOT a factor affecting acid secretion?
A. intracellular PCO2
B. carbonic anhydrase level
C. K+ concentration
D. aldosterone concentration
E. none of the above
Answer: E.none of the above
632. Regarding the kidney:
A. glucose is reabsorbed mainly in distal tubule
B. normal GFR is 125ml/hour
C. glomeruli filter 180L fluid per day
D. Na+ is actively transported out of think loop of Henle
E. ethanol promotes vasopressin secretion
Answer: C.glomeruli filter 180L fluid per day
633. Regarding renal blood flow:
A. blood flow greatest to medulla
B. pressure in renal vein is about 20mmHg
C. angiotensin II constricts efferent arterioles
D. prostaglandins increase blood flow in cortex and medulla
E. renal blood flow = renal plasma flow x 1 haematocrit
Answer: C.angiotensin II constricts efferent arterioles
634. Osmolality of tubular fluid:
A. isotonic in proximal tubule
B. isotonic in loop of Henle
C. hypertonic in ascending limb loop of Henle
D. hypotonic in collecting duct
E. hypotonic in proximal tubule
Answer: A.isotonic in proximal tubule
635. Regarding the kidney and urine formation:
A. specific gravity is measure of osmolality
B. thin ascending limb relatively impermeable to water
C. thin ascending limb relatively impermeable to Na+ Cl-
D. water diuresis begins about 1 hour after ingestion of a water load
E. high protein diet does not affect concentrating ability of kidney
Answer: B.thin ascending limb relatively impermeable to water
636. Regarding tubular reabsorption in kidney:
A. glucose and amino acids passively reabsorbed
B. Cl- mainly actively reabsorbed
C. only passive reabsorption occurs in proximal tubule
D. urea is not passively reabsorbed
E. Na+ actively reabsorbed in most parts of tubule
Answer: E.Na+ actively reabsorbed in most parts of tubule
637. In the presence of vasopressin, most filtered water is absorbed in the:
A. proximal tubule
B. loop of Henle
C. distal tubule
D. cortical collecting system
E. medullary collecting system
Answer: A.proximal tubule
638. All of the following affect glomerular filtration, EXCEPT:
A. changes in renal flood flow
B. urethral obstruction
C. dehydration
D. oedema outside the renal capsule
E. glomerular capillary permeability
Answer: D.oedema outside the renal capsule
639. The thick ascending limb of the loop of Henle:
A. is impermeable to water
B. has maximal permeability to NaCl
C. is relatively permeable to water
D. is impermeable to NaCl
E. is a site where there is no active transport of sodium
Answer: A.is impermeable to water
640. In the normal bladder, micturition:
A. is initiated by the pelvic nerves
B. is co-ordinated in the lumbar portion of the spinal cord
C. is initiated at a volume of 600mls
D. is significantly affected by sympathetic nerves
E. is not facilitated at the level of the brain stem
Answer: A.is initiated by the pelvic nerves
641. All the following statements regarding the atrial natriuretic peptide (ANP) are trueEXCEPT:
A. it causes natriuresis
B. it lowers blood pressure
C. circulating ANP has a short half-life
D. ANP has the greatest affinity for the ANPR-B receptor of the glomerulus
E. it is released when atrial muscle is stretched
Answer: D.ANP has the greatest affinity for the ANPR-B receptor of the glomerulus
642. Which part of the renal tubule is Na+ NOT actively transported out of?
A. proximal convoluted tubule
B. thin portions of the loop of Henle
C. thick ascending limb of loop of Henle
D. distal convoluted tubule
E. collecting duct
Answer: B.thin portions of the loop of Henle
643. Where is the macula densa located?
A. afferent arteriole
B. efferent arteriole
C. proximal convoluted tubule
D. thick ascending limb of loop of Henle
E. distal convoluted tubule
Answer: D.thick ascending limb of loop of Henle
644. What percentage of cardiac output goes to the kidneys at rest?
A. 10%
B. 15%
C. 25%
D. 35%
E. 45%
Answer: C.25%
645. Which factor increases renal blood flow?
A. α1 adrenergic stimulation
B. α2 adrenergic stimulation
C. reduced systemic blood pressure
D. exercise
E. lying down
Answer: E.lying down
646. Angiotensin II:
A. constricts afferent arterioles only
B. constricts efferent arterioles only
C. constricts afferent and efferent arterioles
D. dilates afferent arterioles
E. dilates efferent arterioles
Answer: C.constricts afferent and efferent arterioles
647. Regarding nephrons permeability:
A. glomerular capillaries are 100 times more permeable than skeletal muscle capillaries
B. anionic substances are more permeable than neutral substances
C. N (?normal) glomerular concentration of albumin is 0.2% of plasma concentration
D. neutral substances are freely filtered with diameters < 8nm
E. 100mg/d of protein is filtered at the glomerulus
Answer: C.N (?normal) glomerular concentration of albumin is 0.2% of plasma concentration
648. Where does glucose reabsorption occur?
A. proximal convoluted tubule
B. thin descending limb of loop of Henle
C. thick ascending limb of loop of Henle
D. distal convoluted tubule
E. collecting duct
Answer: A.proximal convoluted tubule
649. Vasopressin acts as the:
A. proximal convoluted tubule
B. loop of Henle
C. distal convoluted tubule
D. cortical portion of the collecting duct
E. medullary portion of the collecting duct
Answer: D.cortical portion of the collecting duct
650. Regarding the bladder:
A. the external urethral sphincter is made up of smooth muscle cells
B. the internal urethral sphincter does not encircle the urethra
C. pelvic nerves (S2-S4) supply the external sphincter
D. when the bladder is stretched, tension is maintained
E. relaxation of the internal urethral sphincter assists micturition
Answer: B.the internal urethral sphincter does not encircle the urethra
651. Which substance relaxes mesangial cells?
A. angiotensin II
B. ADH
C. noradrenaline
D. thromboxane A2
E. ANP
Answer: E.ANP
652. Concerning the kidneys:
A. normal glomerular filtration rate is 250ml/minute
B. normal renal plasma flow is 125ml/minute
C. normal filtration fraction is 0.19
D. blood flow is normally higher in the medulla than the cortex
E. normal blood volume in the kidneys at any one time is 250ml
Answer: C.normal filtration fraction is 0.19
653. Regarding renal handling of substances:
A. urea is filtered, but not secreted
B. most sodium is resorbed in the loop of Henle
C. creatinine is not filtered, but is resorbed
D. potassium is filtered, but not secreted
E. chloride is secreted and resorbed
Answer: A.urea is filtered, but not secreted
654. Which of the following is transported via active transport?
A. chloride
B. hydrogen
C. glucose
D. urea
E. bicarbonate
Answer: B.hydrogen
655. Concerning the respiratory exchange ration (R)
A. it falls during exercise
B. it falls in metabolic acidosis
C. the stomach has a positive R during secretion of acid
D. it rises after ingestion of alkali
E. at steady state, it equals the respiratory quotient
Answer: E.at steady state, it equals the respiratory quotient
656. Regarding fat metabolism, all are true EXCEPT:
A. brown fat is characterised by a H+ short circuit protein in the mitochondria
B. heparin is a cofactor for lipoprotein lipase
C. ketone bodies accumulate in diabetic ketoacidosis due to reduced removal from the circulation
D. the essential fatty acids are used to produce autocoids
E. there is no major pathway for converting fat to carbohydrate
Answer: D.the essential fatty acids are used to produce autocoids
657. Triiodothyronine:
A. is less potent than thyroxine
B. deficiency causes yellow skin due to keratin buildup
C. acts via a tyrosine kinase predominantly
D. causes an increase in Na+ /K+ ATPase activity
E. in both, deficiency but no excess leads to muscle weakness
Answer: E.in both, deficiency but no excess leads to muscle weakness
658. Mesangial cells:
A. have a role in the control of GFR
B. are similar to other endothelial cells in the vascular tree
C. are responsible for tubuloglomerular balance
D. contract in response to dopamine
E. relax in response to vasopressin
Answer: A.have a role in the control of GFR
659. With regard to water excretion:
A. 280 l is filtered per day
B. it is impossible to excrete more than 23 l/day
C. most regulation is via manipulation of the gradients along the loop of Henle
D. vasopressin acts to insert water channels into the basolateral cell membrane of the collecting ducts
E. water reabsorption in the collecting ducts can alter by a factor of 2.5 dependent on the presence of vasopressin
Answer: E.water reabsorption in the collecting ducts can alter by a factor of 2.5 dependent on the presence of vasopressin
660. All of the following are transported across renal tubular cell membranes by secondary active transport, using the energy of the active transport of Na+ , EXCEPT:
A. glucose
B. lactate
C. citrate
D. H+
E. K+
Answer: E.K+
661. Regarding the control of GFR:
A. increasing ANP causes contraction of mesangial cells
B. glomerular cap are less permeable than skeletal
C. oedema of kidney causes increase in renal intent po????
D. efferent arterioles have low reninlard
E. hypoproteinaemia increases GFR
Answer: C.oedema of kidney causes increase in renal intent po????
662. Regarding osmotic diuresis:
A. is secondary to decreased ADH
B. results in hypertonic urine
C. increased water reabsorption in PCT
D. may be seen in patients with diabetes ketoacidosis
E. may be seen in patients with diabetes insipidis
Answer: D.may be seen in patients with diabetes ketoacidosis
663. Effective renal plasma flow is best measured using:
A. inulin
B. glucose
C. PAH
D. urea
E. creatinine
Answer: C.PAH
664. Substance X is freely filtered by the glomerulus and is not reabsorbed, nor secreted nor metabolized.
If – serum x concentration = 0.020 mg/ml
renal artery x concentration = 0.020 mg/ml
renal vein x concentration = 0.002 mg/ml
urine x concentration = 14 mg/ml
urine flow = 54 ml/hr
lymphatic x concentration = 0.00001 mg/ml
haematocrit = 0.45
Then the CLEARANCE of X is:
A. 10.5 ml/min
B. 630 ml/min
C. 10.5 mg/min
D. 630 mg/min
E. 60 ml/min
Answer: B.630 ml/min
665. Substance X is freely filtered by the glomerulus and is not reabsorbed, nor secreted nor metabolized.
If – serum x concentration = 0.020 mg/ml
renal artery x concentration = 0.020 mg/ml
renal vein x concentration = 0.002 mg/ml
urine x concentration = 14 mg/ml
urine flow = 54 ml/hr
lymphatic x concentration = 0.00001 mg/ml
haematocrit = 0.45
Renal plasma flow is:
A. 10.5 ml/min
B. 630 ml/min
C. 700 ml/min
D. 11.7 ml/min
E. 21.2 ml/min
Answer: C.700 ml/min
666. Substance X is freely filtered by the glomerulus and is not reabsorbed, nor secreted nor metabolized.
If – serum x concentration = 0.020 mg/ml
renal artery x concentration = 0.020 mg/ml
renal vein x concentration = 0.002 mg/ml
urine x concentration = 14 mg/ml
urine flow = 54 ml/hr
lymphatic x concentration = 0.00001 mg/ml
haematocrit = 0.45
Renal blood flow is:
A. 10.5 ml/min
B. 21.2 ml/min
C. 11.7 ml/min
D. 700 ml/min
E. 1273 ml/min
Answer: E.1273 ml/min
667. Substance X is freely filtered by the glomerulus and is not reabsorbed, nor secreted nor metabolized.
If – serum x concentration = 0.020 mg/ml
renal artery x concentration = 0.020 mg/ml
renal vein x concentration = 0.002 mg/ml
urine x concentration = 14 mg/ml
urine flow = 54 ml/hr
lymphatic x concentration = 0.00001 mg/ml
haematocrit = 0.45
The GFR is:
A. 10.5 ml/min
B. 700 ml/min
C. 11.7 ml/min
D. 630 ml/min
E. 778 ml/min
Answer: D.630 ml/min
chapter:
Respiration
668. Which is CORRECT?
A. voluntary control of breathing originates in the pons/medulla
B. automatic breathing control descends to the respiratory musculature via the corticospinal tract
C. the reciprocal innervation in automatic breathing is via descending pathways rather than spinal reflexes
D. automatic fibres descend to innervate the external intercostal muscles at each thoracic level to mediate expiration
E. there is no output to the phrenic nerves during expiration
Answer: C.the reciprocal innervation in automatic breathing is via descending pathways rather than spinal reflexes
669. Which abolishes automatic respiration? Destruction of:
A. pre-Bottzinger complexes
B. ventral gp respiratory neurons
C. dorsal gp respiratory neurons
D. section at the inferior border of the pons
E. transaction rostral to the pons
Answer: A.pre-Bottzinger complexes
670. Which does not stimulate carotid bodies?
A. carbon monoxide poisoning
B. cyanide poisoning
C. hypoxia
D. hypercapnia
E. increased H+ concentration
Answer: A.carbon monoxide poisoning
671. All of the following shift the Hb dissociation curve to the right during exerciseEXCEPT:
A. increased 2,3 DPG
B. increased pCO2
C. increased temperature
D. decreased pO2
E. increased H+ concentration
Answer: D.decreased pO2
672. Hypoxia at high altitudes:
A. is a form of stagnant hypoxia
B. causes symptoms of cyanosis
C. causes severe symptoms in an unacclimatised person at 3,000m
D. can always be reversed with 100% O2
E. increased H+ concentration
Answer: B.causes symptoms of cyanosis
673. Regarding surfactant:
A. infant respiratory distress syndrome can be adequately treated with administration of phospholipids alone
B. cigarette smokers have the same amount of surfactant as non-smokers
C. the phospholipid film is formed by tubular myelin
D. infant respiratory distress syndrome is caused by insufficient surfactant that prevents the alveoli from expanding at first inspiratory effort
E. formation of the phospholipid film is greatly facilitated by the carbohydrate in surfactant
Answer: C.the phospholipid film is formed by tubular myelin
674. Regarding the work of breathing during quiet inspiration:
A. elastic work = 80%
B. viscous resistance = 7%
C. airway resistance = 13%
D. when tidal volume versus intrapleural pressure in quiet inspiration are plotted, a straight line results
E. the amount of elastic work required to inflate the whole respiratory system is more than the amount required to inflate the lungs alone
Answer: B.viscous resistance = 7%
675. Regarding gas exchange in the lungs:
A. PaO2 in pulmonary capillaries is the same as PaO2 in the aorta
B. diffusing capacity for O2 (DLO2) increases from 25→65ml/min/mmHg during exercise
C. DLO2 is unaffected by beryllium poisoning and sarcoidosis
D. CO2 retention is frequently a problem in patients with alveolar fibrosis
E. decreased secretion of PDGF by alveolar macrophages causes pulmonary fibrosis
Answer: B.diffusing capacity for O2 (DLO2) increases from 25→65ml/min/mmHg during exercise
676. Regarding gas exchange in the lungs:
A. N2O is diffusion limited
B. CO is perfusion limited
C. O2 is between N2O and CO but at rest, is perfusion limited
D. diffusing capacity of the lung for a gas is inversely proportionate to the surface area of the alveolocapillary membrane and directly proportional to its thickness
E. at rest, it takes blood 0.25secs to traverse the pulmonary capillaries
Answer: C.O2 is between N2O and CO but at rest, is perfusion limited
677. Regarding bronchial tone:
A. substance P causes bronchoconstriction
B. constriction is caused by sympathetic discharge
C. dilation is caused by parasympathetic discharge
D. maximal bronchoconstriction occurs at 4am
E. VIP causes bronchoconstriction
Answer: A.substance P causes bronchoconstriction
678. Regarding pulmonary function, which of the following is NOT true?
A. FRC = ERV + RV
B. IRV in men is about 3,3L
C. RV in women is about 1.1L
D. inspiratory capacity in men = 4.8L
E. total lung capacity = 6L in men, 4.2L in women
Answer: D.inspiratory capacity in men = 4.8L
679. Regarding the glottis:
A. when laryngeal adductors are paralysed there is inspiratory stridor
B. abductors contract early in inspiration
C. when abductors are paralysed, aspiration pneumonia may result
D. the adductors are supplied by the vagus nerves, the abduction by the hypoglossal nerve
E. in animals with bilateral cervical vagotomy, pulmonary oedema is purely secondary to aspiration
Answer: B.abductors contract early in inspiration
680. Regarding oxygen transport:
A. Haemoglobin S has glutamic acid instead of valine in the β chains
B. the O2 saturation of Hb is the percentage of available binding sites that do not have O2 attached
C. the oxygenated form of Hb is the T state
D. cyanosis is more obvious in anaemic patients
E. normal P50 is 27mmHg
Answer: E.normal P50 is 27mmHg
681. Regarding the O2 dissociation curve:
A. O2 affinity of Hb is reduced when the curve is shifted to the left
B. decreased 2,3-DPG shifts the curve to the right
C. the Bohr effect is attributed to the action of PCO2 on H+ concentration
D. temperature has no effect on the curve
E. 2,3-DPG levels are reduced at altitude
Answer: C.the Bohr effect is attributed to the action of PCO2 on H+ concentration
682. Diffusion is inversely proportional to:
A. the diffusion constant
B. tissue area
C. solubility of the gas
D. square root of the molecular weight
E. the difference in partial pressure
Answer: D.square root of the molecular weight
683. In exercise:
A. oxygen consumption is about 6L/min in a moderately fit subject
B. the respiratory exchange ratio rises to 0.8
C. diffusing capacity increases 3-fold
D. the change in cardiac output is only about a sixth of the increase in ventilation
E. the oxygen dissociation curve moves to the left
Answer: C.diffusing capacity increases 3-fold
684. Central respiratory chemoreceptors:
A. are located in the medulla near exit of cranial nerve X, XI
B. respond directly to changes in external PCO2
C. respond directly to changes in arterial PO2
D. are located on dorsal surface of medulla
E. respond to pH of CSF
Answer: E.respond to pH of CSF
685. Respiratory peripheral chemoreceptors:
A. carotid bodies respond to PO2, PCO2, and pH
B. peripheral chemoreceptor response to arterial PCO2 is more important than central chemoreceptor response
C. aortic bodies are located within the aortic valve ring
D. drop in PO2 < 100mmHg causes increase in firing rate
E. carotid bodies respond to venous PO2
Answer: D.drop in PO2 < 100mmHg causes increase in firing rate 686. Ventilatory response to CO2 is reduced by all EXCEPT: A. sleep B. barbiturate overdose C. increasing age D. decreasing the work of breathing E. trained athletes and divers discuss D.decreasing the work of breathing 687. The surface area of the lungs is: A. three times the area of skin B. ten times the area of skin C. 30 times the area of skin D. 100 times the area of skin E. none of the above discuss C.30 times the area of skin 688. Site of most / major airway resistance is: A. trachea B. main bronchi C. large bronchi D. medium sized bronchi E. bronchioles discuss D.medium sized bronchi 689. The volume of the anatomical dead space is: A. 50mL B. 100mL C. 150mL D. 200ml E. 300ml discuss C.150mL 690. Which respiratory volume is INCORRECT? A. tidal volume is the normal breathing volume B. vital capacity is the volume from maximal inspiration followed by maximal expiration C. residual volume is the volume remaining in lungs after maximal expiration D. functional residual capacity is the volume after normal inspiration E. total lung capacity is the vital capacity plus residual volume discuss D.functional residual capacity is the volume after normal inspiration 691. The diffusion constant is proportional to: A. tissue thickness B. square root of the molecular weight C. difference in partial pressures D. tissue area E. gas solubility discuss E.gas solubility 692. Mean pressure (mmHg) in the main pulmonary artery is: A. 2 B. 5 C. 8 D. 15 E. 25 discuss D.15 693. Regarding pulmonary blood flow: A. increased arterial pressure leads to increased pulmonary vascular resistance B. localised vasoconstriction is directly due to arterial PO2 hypoxia C. regional differences are due to hydrostatic pressure differences D. at the apex Pa>Pv>PA
E. pulmonary arteries and veins have transmural pressures equal to alveolar pressure
Answer: C.regional differences are due to hydrostatic pressure differences
694. Which is not inactivated by the lungs?
A. serotonin
B. bradykinin
C. leukotrienes
D. prostaglandin E2
E. vasopressin
Answer: E.vasopressin
695. Regarding the alveolar gas equation:
A. the respiratory quotient nears 1.0 with exercise
B. PIO2= barometric pressure – water vapour pressure
C. PACO2 > PaCO2
D. PAO2 is normally 150mmHg
E. remains valid if there is CO2 present in the inspired gas
Answer: A.the respiratory quotient nears 1.0 with exercise
696. The amount of O2 in blood with a PaO2 of 100mmHg is:
A. 0.003ml O2/100ml
B. 0.3ml O2/100ml
C. 3ml O2/100ml
D. 3ml O2/mL
E. 0.3ml O2/L
Answer: B.0.3ml O2/100ml
697. Regarding the O2 dissociation curve:
A. increased PCO2 has a direct effect on the curve, shifting it to the right
B. 2,3-DPG levels rise as altitude
C. the deoxy form of Hb is in the relaxed state
D. CO moves the curve to the left as it has 100 times the affinity of O2 for Hb
E. P50 is at a PO2 of 40mmHg
Answer: B.2,3-DPG levels rise as altitude
698. Which respiratory principle is INCORRECT?
A. Fick’s law states that “the volume of gas per unit time that moves across a sheet of tissue is proportional to the area of the sheet, but inversely proportional to its thickness”
B. the Bohr effect is “the effect of PCO2 on the O2 dissociation curve due to the action of PCO2 on H+ concentration”
C. Henry’s law states that “the amount of gas dissolved is proportional to the partial pressure of that gas”
D. the chloride shift is “the diffusion of HCO3 – in to the cell, with the outward diffusion of Cl- ions to maintain electrical neutrality”
E. the Haldane effect is that deoxygenation of the blood increases its ability to carry CO2
Answer: D.the chloride shift is “the diffusion of HCO3 – in to the cell, with the outward diffusion of Cl- ions to maintain electrical neutrality”
699. Given a PCO2 = 600mmHg and a HCO3- = 28mEq/l there is a:
A. metabolic acidosis
B. metabolic acidosis with renal compensation
C. respiratory acidosis
D. respiratory acidosis with renal compensation
E. respiratory alkalosis
Answer: C.respiratory acidosis
700. Regarding the elastic properties of the lung:
A. the lung volume at any given pressure during inflation is larger than during deflation
B. the area under the pressure-volume curve is known as the compliance
C. surface tension is the force acting across an imaginary line in the surface of the liquid
D. pressure generated in an alveolus equals 4T/R
E. surfactant, produced by Type I alveolar cells, reduces surface tension in alveoli
Answer: C.surface tension is the force acting across an imaginary line in the surface of the liquid
701. Halving the radius of an airway increases resistance:
A. 2-fold
B. 4-fold
C. 8-fold
D. 16-fold
E. has no effect on resistance
Answer: D.16-fold
702. The major site of resistance in the bronchial tree is the:
A. segmental bronchii
B. medium-sized bronchii
C. small bronchii
D. large bronchioles
E. terminal bronchioles
Answer: B.medium-sized bronchii
703. Lung compliance increases with:
A. asthma
B. alveolar oedema
C. pulmonary hypertension
D. atelectasis
E. pulmonary fibrosis
Answer: A.asthma
704. The ventilatory response to CO2 is increased by:
A. sleep
B. increasing age
C. trained athlete
D. morphine
E. decreased PO2
Answer: E.decreased PO2
705. Normally the FEV1 is what percentage of FVC?
A. 50%
B. 60%
C. 70%
D. 80%
E. 90%
Answer: D.80%
706. The calibre of extra-alveolar vessels is primarily determined by:
A. the difference between alveolar pressure and the pressure within them
B. the pressure in the pulmonary artery
C. the lung volume
D. the cardiac output
E. the patient’s fluid status
Answer: C.the lung volume
707. Which statement regarding hyperbaric oxygen therapy is INCORRECT?
A. males eliminate carboxy haemoglobin faster than females
B. gas around the body is normal air compressed to the same high pressure
C. it produces marked increases in dissolved oxygen in the blood
D. oxygen is administered at up to 3 atmospheres pressure
E. toxicity includes optic neuritis
Answer: A.males eliminate carboxy haemoglobin faster than females
708. All of the following are features of acclimatisation to high altitude EXCEPT:
A. shift to the right of the oxygen dissociation curve
B. increased number of capillaries in peripheral tissues
C. pulmonary vasodilation
D. polycythaemia
E. increased maximum breathing capacity
Answer: C.pulmonary vasodilation
709. Which of the following statements is TRUE?
A. pulmonary stretch receptors lie within the airway epithelial cells
B. J receptors, when stimulated, cause slow deep breathing
C. irritant receptors, when stimulated, send impulses up the vagus in unmyelinated fibres
D. irritant receptors are rapidly adapting
E. increased maximum breathing capacity
Answer: D.irritant receptors are rapidly adapting
710. Which one of the following statements regarding ventilation is INCORRECT?
A. tidal volume in the average human is 500ml
B. anatomical dead space is the volume of the conducting airway and is about 160ml
C. upper regions of the lung ventilate better than the lower regions
D. you can measure physiological dead space via Bohr’s method to get what is called a Bohr equation which is: VD PACO2-PECO2 VT PACO2
E. None of the above
Answer: C.upper regions of the lung ventilate better than the lower regions
711. The diffusion capacity (DI) of the lung accounts for:
A. P1-P2
B. area of lung
C. the thickness
D. diffusion constant
E. all of the above
Answer: A.P1-P2
712. Regarding movement to high altitude, which statement is INCORRECT?
A. hyperventilation occurs due to hypoxic stimulation of peripheral chemoreceptors
B. pro-erythroblasts mature into erythrocytes more rapidly than normal
C. renal bicarbonate excretion increases
D. increased numbers of mitochondria appear in the tissues
E. FiO2 decreases with increasing altitude
Answer: E.FiO2 decreases with increasing altitude
713. Metabolic functions of the lung include all of the following EXCEPT:
A. conversion of AI to AII by ACE
B. metabolism of AII
C. inactivation of bradykinin
D. removal of serotonin
E. metabolism of arachidonic acid metabolises
Answer: B.metabolism of AII
714. Which of the following is INCORRECT?
A. O2 toxicity causes convulsion
B. O2 at 100% in premature infants causes retrolental fibroplasia
C. acclimatisation to high altitudes include a shift to the left of the O2 dissociation curve
D. polycythaemia is a feature of acclimatisation
E. acute mountain sickness is due to hypoxaemia and alkalosis
Answer: C.acclimatisation to high altitudes include a shift to the left of the O2 dissociation curve
715. Regarding the neural control of breathing, which statement is INCORRECT?
A. medullary centres are close to but separate from central chemoreceptors
B. during quiet respiration, expiration is a passive event
C. inspiratory medullary neurons supply both phrenic nerves
D. ventral medullary neurons are expiratory and do not discharge spontaneously
E. inspiratory medullary neurons discharge spontaneously at a rate of 12-15 times/minute
Answer: D.ventral medullary neurons are expiratory and do not discharge spontaneously
716. The transport of which of the following gases is DIFFUSION LIMITED?
A. O2
B. N2O
C. CO2
D. CO
E. halothane
Answer: D.CO
717. With regard to anatomic dead space, all of the following are true EXCEPT:
A. it is calculated by Bohr’s method
B. the normal value is about 150ml
C. it increases with large inspirations
D. depends on the size of the subject
E. it is equivalent to the conducting zone
Answer: A.it is calculated by Bohr’s method
718. Which of the following is INCORRECT?
A. haemoglobin S causes the O2 curve to shift to the left
B. the O2 dissociation curve is shifted to the right by an increased PCO2, H+ concentration and temperature
C. carboxy haemoglobin has 240 times the affinity of O2 for Hb
D. COHB shift the O2 dissociation over to the left
E. it is equivalent to the conducting zone
Answer: A.haemoglobin S causes the O2 curve to shift to the left
719. Regarding the chemical control of breathing, which statement is INCORRECT?
A. central chemoreceptors are located in the medulla oblongata
B. hypoxia makes an individual more sensitive to increases in arterial carbon dioxide
C. arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies
D. carotid bodies have the highest blood flow, per unit time per 100g, of any tissue in the body
E. carbon dioxide is more important than oxygen in respiratory control
Answer: C.arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies
720. Fick’s law states that:
A. Va = (VCO2/PCO2) x K
B. V = (A.D.(P1 – P2))/T
C. pH – -LOG[H+]
D. P1V1 = P2V2
E. V1/V2 = T1/2
Answer: B.V = (A.D.(P1 – P2))/T
721. Regarding surfactant, which statement is INCORRECT?
A. it predominantly consists of phospholipid
B. it is increased by long-term 100% oxygen therapy
C. hydrophobic “tails” face into alveolar lumen
D. it is decreased by cigarette smoking
E. pulmonary oedema is a consequence of its absence
Answer: B.it is increased by long-term 100% oxygen therapy
722. Which of the following DOES NOT shift the O2 dissociation curve to the right?
A. increased temperature
B. increased PCO2
C. increased H+
D. increased DPG
E. increased carboxy haemoglobin
Answer: E.increased carboxy haemoglobin
723. Regarding exercise, which statement is INCORRECT?
A. the energy cost of breathing is up to 10% of total energy expenditure
B. total pulmonary ventilation increases by up to 20 fold
C. total oxygen consumption increases by up to 20 fold
D. total carbon dioxide production increases by up to 40 fold
E. P5O increases
Answer: A.the energy cost of breathing is up to 10% of total energy expenditure
724. Total lung capacity is equal to:
A. vital capacity + tidal volume
B. vital capacity + functional residual capacity
C. tidal volume + residual volume
D. functional residual capacity + tidal volume
E. vital capacity + residual volume
Answer: E.vital capacity + residual volume
725. Regarding compliance, which statement is INCORRECT?
A. functional residual capacity is the equilibrium volume when elastic recoil of lung is balanced by normal tendency for chest wall to spring out
B. hysteresis is due to frictional resistance to air movement
C. compliance is greater in expiration than in inspiration
D. compliance is increased in emphysema
E. compliance is a dynamic measure of lung and chest wall recoil
Answer: E.compliance is a dynamic measure of lung and chest wall recoil
726. Which of the following is NOT involved in the control of ventilation?
A. peripheral chemoreceptors
B. lung stretch receptors
C. basal ganglia
D. pons
E. respiratory muscles
Answer: C.basal ganglia
727. Which of the following DOES NOT decrease lung compliance?
A. left ventricular failure
B. atelectasis
C. pulmonary fibrosis
D. advancing age
E. raised pulmonary capillary wedge pressure
Answer: D.advancing age
728. Regarding ventilation / perfusion (V/Q) relationships, which statement is INCORRECT?
A. V/Q ratio is greatest at the lung apex
B. V/Q ratio is about one at level of third rib when upright
C. ventilation decreases proportionately more than perfusion from base to apex
D. V/Q ratio for whole lung at rest is about 0.8
E. exercise increases the V/Q ratio
Answer: C.ventilation decreases proportionately more than perfusion from base to apex
729. Regarding pulmonary perfusion, which statement is INCORRECT?
A. apical perfusion is less than basal
B. E.coli endotoxin causes venodilatation
C. total pulmonary blood flow increases 3-6 fold during exercise
D. pulmonary vascular resistance increases at small lung volumes
E. in zone 2, pulmonary arterial pressure is greater than alveolar pressure
Answer: B.E.coli endotoxin causes venodilatation
730. Regarding pulmonary ventilation, which statement is INCORRECT?
A. physiological dead space is normally larger than anatomical dead space
B. basal ventilation is greater than apical
C. normal tide volume is about 7ml/kg
D. airway resistance decreases at large lung volumes
E. total pulmonary ventilation can increase by up to 20 fold during exercise
Answer: A.physiological dead space is normally larger than anatomical dead space
731. Which of the following DOES NOT constrict pulmonary arterioles?
A. adrenaline
B. thromboxane B2
C. noradrenaline
D. prostaglandin F2 α
E. isoproteronol
Answer: E.isoproteronol
732. Regarding the lung volumes in a healthy 70kg male, 183cm tall, which isINCORRECT?
A. tidal volume = 500ml
B. residual volume = 1200ml
C. expiratory reserve volume = 1000ml
D. inspiratory capacity = 3300ml
E. vital capacity = 4800ml
Answer: D.inspiratory capacity = 3300ml
733. Regarding carbon dioxide transport in blood, which statement is INCORRECT?
A. oxygen is about 20 times less soluble in blood
B. deoxygenation of blood increase its ability to carry carbon dioxide
C. arterial blood transports about 20% in dissolved form
D. venous blood has higher haematocrit than arterial blood
E. carbamino compounds are formed by reaction with both plasma proteins and Hb
Answer: C.arterial blood transports about 20% in dissolved form
734. Which of the following does NOT increases synthesis of 2, 3-DPG?
A. growth hormone
B. phosphate deficiency
C. thyroid hormone
D. exercise for one hour
E. androgens
Answer: B.phosphate deficiency
735. Which of the following DOES NOT shift the oxygen-haemoglobin dissociation curveto the right?
A. decreased phosphate
B. increased altitude
C. cortisol
D. decreased pH
E. aldosterone
Answer: A.decreased phosphate
736. Regarding alveolar cells, which statement is INCORRECT?
A. type I pneumocytes repair alveolar epithelium
B. pulmonary alveolar macrophages are derived from blood monocytes
C. mast cell membranes bind IgE via Fc portion to heavy chain
D. APUD (neuroendocrine) cells are of endodermal origin
E. type II pneumocytes are membranous
Answer: E.type II pneumocytes are membranous
737. Which of the following substances is NOT removed from the blood by the lung?
A. prostaglandins
B. noradrenaline
C. acetylcholine
D. adrenaline
E. bradykinin
Answer: D.adrenaline
738. Which statement regarding gas exchange in the lungs is INCORRECT?
A. gases generally cross by simple diffusion
B. diffusion capacity for carbon dioxide is much greater than for oxygen
C. nitrous oxide is a diffusion limited gas
D. carbon monoxide does not reach equilibrium in 0.75 seconds
E. oxygen is a perfusion limited gas
Answer: C.nitrous oxide is a diffusion limited gas
739. Which of the following substances is NOT synthesised by the lung?
A. prostaglandins
B. serotonin
C. dipalmityl phosphatidylcholine
D. histamine
E. kallikrein
Answer: B.serotonin
740. Exercise has all of the following effects on blood gases EXCEPT:
A. increased PACO2
B. increased PAO2
C. unchanged PaCO2
D. unchanged PaO2
E. increased PvCO2
Answer: A.increased PACO2