Question 1

Which of the following best describes the function of the myelin sheath in the peripheral nervous system?

Accepted Answer

It insulates axons and enables rapid saltatory conduction of action potentials.

Question 2

A patient presents with paralysis of facial muscles on one side, inability to close the eye, and partial loss of taste sensation. Which cranial nerve is most likely affected?

Accepted Answer

Facial nerve (VII)

Question 3

Damage to the optic nerve (II) results in which of the following clinical outcomes?

Accepted Answer

Blindness in the eye served by the nerve

Question 4

Which cranial nerve is responsible for abduction of the eyeball, and what is the consequence of its paralysis?

Accepted Answer

Abducens nerve (VI); eye cannot move laterally and rotates medially at rest

Question 5

Which of the following cranial nerves contains both somatic motor fibers and parasympathetic fibers?

Accepted Answer

Oculomotor nerve (III)

Question 6

A patient is unable to protrude their tongue and has difficulty swallowing. Which cranial nerve is most likely damaged?

Accepted Answer

Hypoglossal nerve (XII)

Question 7

Which of the following best describes the relationship between stimulus strength and action potential frequency?

Accepted Answer

A stronger stimulus increases the frequency of action potentials.

Question 8

Which cranial nerve is involved in both taste sensation from the posterior tongue and regulation of blood pressure via baroreceptors?

Accepted Answer

Glossopharyngeal nerve (IX)

Question 9

Which of the following is a correct classification of spinal nerves?

Accepted Answer

All spinal nerves are mixed nerves, containing both sensory and motor fibers.

Question 10

A patient presents with stabbing facial pain triggered by brushing their teeth. Which condition and nerve are most likely involved?

Accepted Answer

Trigeminal neuralgia; trigeminal nerve (V)

Question 11

Which cranial nerve is the only one to extend beyond the head and neck region, and what is its primary function?

Accepted Answer

Vagus nerve (X); regulation of heart, lungs, and abdominal viscera

Question 12

Which of the following best describes saltatory conduction in myelinated axons?

Accepted Answer

Action potentials jump rapidly from one myelin sheath gap to the next.

Question 13

Which cranial nerve is responsible for innervating the superior oblique muscle of the eye, and what is the result of its damage?

Accepted Answer

Trochlear nerve (IV); double vision and impaired ability to rotate eye inferolaterally

Question 14

Which of the following is NOT a function of the oculomotor nerve (III)?

Accepted Answer

Taste sensation from the anterior tongue

Question 15

Which equation describes the threshold for action potential generation?

Accepted Answer

$$V_{m} \geq V_{threshold}$$

Question 16

Which nerve is tested by asking a patient to clench their teeth and move their jaw side to side?

Accepted Answer

Trigeminal nerve (V)

Question 17

Which cranial nerve is most likely affected if a patient experiences central deafness and loss of balance?

Accepted Answer

Vestibulocochlear nerve (VIII)

Question 18

Which of the following best describes the function of the dorsal root ganglion?

Accepted Answer

Contains cell bodies of sensory neurons

Question 19

Which cranial nerves supply parasympathetic autonomic input?

Accepted Answer

Oculomotor (III), Facial (VII), Glossopharyngeal (IX), Vagus (X)

Peripheral Nervous System: Structure, Function, and Cranial Nerves

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