Biology Multiple Choice Questions for AIIMS Exam on “Human Circulatory System – 2”.
1. Identify the valve of the heart.
a) Pulmonary semilunar valve
b) Aortic semilunar valve
c) Tricuspid valve
d) Bicuspid valve
Answer: d
Clarification: In the given diagram of the cross section of the heart, the indicated valve is the bicuspid valve. It is also known as the mitral valve. The bicuspid valve is the opening between the left auricle and left ventricle.
2. Identify the blood vessel of the heart.
a) Aorta
b) Pulmonary artery
c) Superior vena cava
d) Pulmonary aorta
Answer: c
Clarification: In the given diagram of the cross-section of the heart, the indicated structure is the superior vena cava. The superior vena cava delivers deoxygenated blood from the upper parts of the body to the heart.
3. In the joint diastole state, which of these events do not occur?
a) All four chambers are relaxed
b) Both tricuspid and bicuspid valves are open
c) Blood from pulmonary vein flows into the right atrium
d) Both semilunar valves are closed
Answer: c
Clarification: In the joint diastole state, all four chambers of the heart are relaxed. The tricuspid and bicuspid valves are open while the semilunar valves are closed. Blood from pulmonary vein flows into the left ventricle.
4. Which of these occurs during the atrial systole?
a) Both atria contract simultaneously
b) Action potential is generated by the AVN initially
c) Tricuspid valve closes
d) The semilunar valves remain open
Answer: a
Clarification: During the atrial systole, both the atria contract simultaneously while the ventricles remain relaxed. It occurs due to the action potential generated by the SAN. The tricuspid and bicuspid valves open.
5. During atrial systole, blood flow toward the ventricles increases by what percent?
a) 10%
b) 30%
c) 50%
d) 70%
Answer: b
Clarification: During the atrial systole, both the atria contract simultaneously while the ventricles remain relaxed. The increase in pressure in the atria forces 30% more blood to flow into the ventricles.
6. Which structure is not responsible for the transmission of action potential to the ventricles?
a) AV bundle
b) AVN
c) SAN
d) Bundle of His
Answer: c
Clarification: SAN or the sinoatrial node is auto excitable and is responsible for generating the action potential. This action potential is transmitted to the ventricles via the AVN, the AV bundle and the Bundle of His.
7. Which of these events coincide with ventricular systole?
a) Atrial diastole
b) Atrial systole
c) Joint diastole
d) Ventricular diastole
Answer: a
Clarification: The relaxation of the atria or the atrial diastole coincides with the contraction of the ventricles or the ventricular systole. The right and left semilunar valves open up due to the increase in pressure in the ventricles.
8. Which of these events do not occur during ventricular systole?
a) Closure of tricuspid and bicuspid valves
b) Atrial diastole
c) Opening of the semilunar valves
d) Flow of blood from atria to ventricles