9 MCQs on Bioelectrical Physiology

[Anonymous]

You have 9 questions in this exam.


1. Choose one correct answer.
A. The resting membrane potential of most body cells is positive inside and negative outside.
B. If the resting membrane potential is made mode negative it is called hyopolarizartion.
C. If membrane potential moves in the positive direction it is called depolarization.
D. If you put both the measuring electrode (eg, microelectrode) and reference inside of a cell, you will measure a negative voltage.



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Correct Answer: C






2. Choose one correct answer.
A. Phase 0 of a cardiac action potential is the rapid repolarization phase of the action potential.
B. Phase 1 of a cardiac action potential is the upstroke of a cardiac action potential.
C. During phase 4 of a cardiac action corresponds to the plateau phase of the action potential.
D. None are correct.



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Correct Answer: D






3. Choose one correct answer.
A. If efflux of an ion exceeds influx, the ion will accumulate in the cell.
B. The flux of an ion across a cell membrane is equal to the product of membrane conductance to the ion and the driving forces acting on the ion.
C. Normally, the only driving force acting on ions is the membrane potential.
D. None arte correct.



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Correct Answer: B






4. If the resting membrane potential is –100mV and the sodium equilibrium potential is +40mV then what is the value of the electrochemical gradient (ie, total driving force) acting on sodium ions? Choose one correct answer.
A. +60 mV
B. –60 mV
C. –140 mV
D. None are correct.



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Correct Answer: C






5. Choose one correct answer.
A. The lipid bilayer portion of the cell membrane acts like a resistor.
B. If the membrane conductance to an ion is very high and the total electrochemical gradient is zero there will be no net movement of the ion through the membrane.
C. If the concentration gradient of an ion across the membrane is inwardly directed and the electrical gradient is equal and opposite, there will be net movement of the ion into the cell.
D. None are correct.



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Correct Answer: B






6. Choose one correct answer.
A. An increase in plasma potassium concentration will cause resting membrane potential to become more negative.
B. Cardioplegia solutions contain a low concentration of potassium.
C. The upstroke of the nerve action potential is generated by Na influx via the Na-K pump.
D. Action potentials repolarize because the net ionic current is outward.



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Correct Answer: D






7. Choose one correct answer.
A. A reduction in sodium current will increase action potential conduction velocity in nerve.
B. An increase in cell diameter will increase action potential conduction velocity in nerve.
C. An increase in membrane capacitance will increase conduction velocity in heart cells.
D. None are correct.



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Correct Answer: B






8. Choose one correct answer.
A. Skeletal muscle cells are electrically connected via gap junctions.
B. Local circuit currents are not required for action potential propagation.
C. An increase in action potential amplitude will decrease conduction velocity.
D. None are correct.



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Correct Answer: D






9. Choose one correct answer.
A. The refractory period of nerve, heart and skeletal muscle is due to inactivation of sodium channels.
B. The space constant is an index of how far local circuit currents can spread in nerve, heart and skeletal muscle.
C. Closure of gap junctions will increase conduction velocity in heart.
D. None are correct.




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Correct Answer: A

[Cadusma]

What is the source of your questions?

[Anonymous]

my questions are from different sources, but these in particular are from the university of utah. sorry, i usually try to cite my references, but sometimes i forget