Question 1

Which of the following best describes the role of Schwann cells in the regeneration of peripheral nerve fibers?

Accepted Answer

They form the myelin sheath and guide regenerating axon sprouts across the injury site.

Question 2

A patient presents with phantom limb pain after an amputation. Which mechanism best explains this phenomenon?

Accepted Answer

The somatosensory cortex reorganizes and sends mixed signals, resulting in the perception of pain from the missing limb.

Question 3

Which of the following is TRUE regarding the regeneration of nerve fibers in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes in the CNS release growth-inhibiting proteins that prevent axon regeneration.

Question 4

Which neurotransmitter is released at the neuromuscular junction to initiate skeletal muscle contraction?

Accepted Answer

Acetylcholine (ACh)

Question 5

A toxin blocks the release of acetylcholine at the neuromuscular junction. What is the most likely physiological effect?

Accepted Answer

Paralysis of skeletal muscle due to lack of stimulation

Question 6

Which of the following best describes a learned (acquired) reflex?

Accepted Answer

A motor response developed through practice and repetition, such as driving skills

Question 7

Which of the following is NOT a component of a typical reflex arc?

Accepted Answer

Ganglion cell

Question 8

During the process of nerve regeneration in the peripheral nervous system, what is the approximate rate of axon regrowth after the initial rest period?

Accepted Answer

1 mm per day

Question 9

Which division of the peripheral nervous system is responsible for activating skeletal muscle?

Accepted Answer

Somatic nervous system

Question 10

Which of the following best explains why visceral motor responses are slower than somatic motor responses?

Accepted Answer

Visceral motor endings use varicosities and neurotransmitters act indirectly via second messengers.

Question 11

A patient with myasthenia gravis experiences muscle weakness. Which mechanism is responsible for this symptom?

Accepted Answer

Inactivation of acetylcholine receptors at the neuromuscular junction

Question 12

Which of the following equations correctly represents the movement of sodium and potassium ions during depolarization at the neuromuscular junction?

Accepted Answer

$$\Delta V = g_{Na^+}(E_{Na^+} - V) + g_{K^+}(E_{K^+} - V)$$

Question 13

Which of the following is a function of the autonomic (visceral) reflexes?

Accepted Answer

Activation of smooth muscle, cardiac muscle, or glands

Question 14

Which of the following best describes the effect of black widow spider venom at the neuromuscular junction?

Accepted Answer

It causes excessive release of acetylcholine.

Question 15

Which of the following is a clinical significance of testing somatic reflexes?

Accepted Answer

It helps diagnose degeneration or pathology of specific nervous system regions.

Question 16

Which of the following best describes the process of depolarization at the neuromuscular junction?

Accepted Answer

Acetylcholine binds to receptors, causing Na$$^+ to $$enter and K$$^+ to $$exit the muscle cell, leading to an end plate potential.

Question 17

Which of the following is a correct sequence of events in the regeneration of a peripheral nerve fiber?

Accepted Answer

Axon fragments, debris is cleared, axon filaments grow through a regeneration tube, new myelin sheath forms.

Question 18

Which of the following is a characteristic of the neuromuscular junction (NMJ) in skeletal muscle?

Accepted Answer

It is a chemically gated synapse with a single, long cylindrical muscle cell innervated by a motor neuron.

Question 19

Which of the following best explains why moderate exercise can speed nerve healing after injury?

Accepted Answer

Exercise increases blood flow, which enhances nutrient delivery and waste removal, promoting regeneration.

Peripheral Nervous System: Structure, Function, and Regeneration

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