Question 1

Which connective tissue layer directly surrounds a bundle of nerve fibers (fascicle) in a peripheral nerve?

Accepted Answer

Perineurium

Question 2

A patient suffers a traumatic injury that severs an axon in the peripheral nervous system (PNS). Which of the following best explains why regeneration is possible in the PNS but not in the central nervous system (CNS)?

Accepted Answer

Schwann cells in the PNS release growth factors and form a regeneration tube to guide axon regrowth.

Question 3

Which cranial nerve is responsible for transmitting visual information from the retina to the brain?

Accepted Answer

Optic (II)

Question 4

During a neurological exam, a patient is unable to move their tongue. Which cranial nerve is most likely damaged?

Accepted Answer

Hypoglossal (XII)

Question 5

Which of the following best describes the function of the dorsal root ganglion in the spinal cord?

Accepted Answer

It contains sensory (afferent) neuron cell bodies.

Question 6

A patient presents with loss of sensation in the anterior thigh. Which plexus is most likely involved?

Accepted Answer

Lumbar plexus

Question 7

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

Accepted Answer

Myelin sheath

Question 8

In the patellar (knee-jerk) reflex, which type of reflex arc is involved?

Accepted Answer

Ipsilateral

Question 9

Which equation correctly represents the relationship between the number of spinal nerves ($N$), the number of vertebrae ($V$), and the number of plexuses ($P$) if $N = V + P$ and there are 31 spinal nerves, 26 vertebrae, and 5 plexuses?

Accepted Answer

$N = V + P$

Question 10

A patient has damage to the ventral root of a spinal nerve. Which function is most likely impaired?

Accepted Answer

Transmission of motor impulses from the spinal cord to effectors

Question 11

Which of the following statements about mixed nerves is correct?

Accepted Answer

They contain both sensory and motor fibers.

Question 12

If the axon of a peripheral neuron is damaged but the soma remains intact, which process is most likely to occur?

Accepted Answer

Wallerian degeneration followed by axon regeneration guided by Schwann cells

Question 13

Which spinal nerve emerges from the brachial plexus and is responsible for innervating the muscles of the anterior forearm?

Accepted Answer

Median nerve

Question 14

A patient is unable to extend their wrist and fingers after a humeral fracture. Which nerve is most likely injured?

Accepted Answer

Radial nerve

Question 15

Which of the following best describes a contralateral reflex arc?

Accepted Answer

Motor activity occurs on the opposite side of the body from the stimulus.

Question 16

Which equation represents the total number of cranial nerves ($C$) if there are 12 cranial nerves and each is assigned a Roman numeral ($R$) from I to XII?

Accepted Answer

$C = 12$

Question 17

Which of the following is a learned (acquired) reflex?

Accepted Answer

Driving a car and pressing the brake pedal in response to a red light

Question 18

If a patient has damage to the sensory (afferent) fibers in the dorsal root, which symptom would most likely be present?

Accepted Answer

Loss of sensation in the area supplied by the affected nerve

Question 19

Which of the following best explains why the CNS does not regenerate axons after injury?

Accepted Answer

Oligodendrocytes do not form regeneration tubes or release growth factors.

Question 20

A patient is unable to flex their elbow after an injury to the upper arm. Which nerve is most likely affected?

Accepted Answer

Musculocutaneous nerve

Peripheral Nervous System: Structure, Function, and Reflexes

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