Biomedical Instrumentation Multiple Choice Questions on “Origin of Bioelectric Signals”.
1. Source of Bioelectric potential is ____________ in nature.
a) electronic
b) electric
c) ionic
d) mechanical
Answer: c
Clarification: Bioelectric potentials are generated at cellular level and the source of these potentials is ionic in nature. The prominent ions are K+, Na+, and Cl–. Electronic potential is seen in commonly used cells for example the Galvanic cell. Mechanical potential is found nowhere. Electrical potential is found in electricity.
2. Palsied muscles mean _____________
a) paralyzed muscles
b) active muscles
c) voluntary muscles
d) involuntary muscles
Answer: a
Clarification: Palsied is an adjective that means paralyzed. It is used to describe a muscle on which an individual has lost all control (cannot move). Voluntary muscles are the muscles on which the individual has complete control. Involuntary muscles are the ones on which the individual has no control for example heart wall muscles.
3. The principal ion that is not involved with the phenomena of producing cell potentials is ______________
a) sodium
b) potassium
c) chlorine
d) hydrogen
Answer: d
Clarification: Sodium (Na+), Potassium (K+), and Chlorine (Cl–) are the principal ions involved with the phenomena of producing cell potentials. Na+ is present outside the cell membrane and creates a positively charged environment outside the cell membrane. Cl– is present inside the cell membrane and is responsible for the negative environment inside the cell membrane.
4. What is the relatively static membrane potential of quiescent cells called?
a) half-cell potential
b) action potential
c) resting membrane potential
d) cell potential
Answer: c
Clarification: Resting membrane potential or the resting potential is the relative static membrane potential of quiescent cell. That is if the resting membrane potential of a neuron is about -70 mV (mV=millivolt) it means that the inside of the neuron is 70 mV less than the outside of the neuron. An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way.
5. The variation of the electrical potential associated with the passage of a pulse along the membrane of a muscle cell or a nerve cell is called __________
a) muscle potential
b) action potential
c) resting potential
d) half cell potential
Answer: b
Clarification: An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way. Resting membrane potential or the resting potential is the relative static membrane potential of a quiescent cell.
6. Cells depolarize and action potential in generated as soon as a stimulus is applied.
a) True
b) False
Answer: b
Clarification: This statement is False. This is because unless a stimulus above a certain minimum value is applied, the cell will not be depolarized and no action potential will be generated. This value of potential above which the depolarizes and an action potential is generated is known as the stimulus threshold.
7. After a cell is stimulated, a finite period of time is required for the cell to return to its pre-stimulus state. This period is known as ____________
a) restoration period
b) refactory period
c) regain period
d) regenerative period