Synaptic Transmission — Nerve & Muscle Physiology

Synaptic Transmission MCQs: practice questions

Sample Synaptic Transmission multiple-choice questions from Nerve & Muscle Physiology.

1. Hyperpolarization means that the membrane potential becomes:

   • A. Less negative
   • B. More positive
   • C. More negative
   • D. Equal to zero
   • E. Equal to ENa

2. Which factor most directly determines whether an ion contributes to membrane potential?

   • A. Its color
   • B. Cell volume alone
   • C. The patient's age
   • D. Membrane permeability to the ion
   • E. ATP concentration alone

3. Increasing extracellular K+ concentration tends to make the resting membrane potential:

   • A. Less negative
   • B. More negative
   • C. Equal to ENa
   • D. Unchanged in all cases
   • E. Positive +120 mV

4. Which feature prevents an action potential from normally traveling backward along an axon?

   • A. Osmosis
   • B. The refractory state of recently activated membrane
   • C. The Na+–K+ pump alone
   • D. Myelin degradation
   • E. Synaptic vesicles

5. A larger myelinated axon conducts faster mainly because it has:

   • A. Higher internal resistance
   • B. No ion channels
   • C. Lower internal resistance
   • D. No membrane capacitance
   • E. No refractory period

6. The undershoot following a neuronal action potential occurs because:

7. Tetrodotoxin produces paralysis by blocking:

8. An increase in Na+ permeability in a resting neuron tends to move Vm:

9. Temporal summation occurs when:

10. A nerve fiber with a larger diameter generally has:

11. A stimulus reaches threshold when depolarizing current is sufficient to:

12. Repolarization refers to:

13. The all-or-none property means that once threshold is reached:

14. Which change most directly increases conduction velocity in a myelinated axon?

15. Spatial summation occurs when:

16. The equilibrium potential for an ion is the membrane potential at which:

17. If a neuron is at EK and K+ channels are open, net K+ current is:

18. Which channel opening is most responsible for repolarization of a typical neuronal action potential?

19. The absolute refractory period is mainly caused by:

20. A local anesthetic blocks voltage-gated Na+ channels. The expected effect is:

21. During the relative refractory period, a second action potential requires a stronger stimulus because:

22. The resting membrane potential of a typical neuron is closest to:

23. The Na+–K+ ATPase maintains neuronal excitability primarily by:

24. Saltatory conduction occurs because action potentials are regenerated at:

25. A subthreshold stimulus applied to a nerve fiber produces:

26. Demyelination most directly causes:

27. Which membrane property is increased by myelination?

28. A membrane potential moves from −70 mV to −50 mV. This is:

29. Which statement best describes a graded potential?

30. Which ion carries the major inward current during the rapid upstroke of a typical neuronal action potential?