Question 1

A patient presents with loss of sensation in a specific region of skin on their forearm. Which of the following best explains the clinical significance of this finding?

Accepted Answer

It indicates damage to a specific dermatome, which can help localize the affected spinal nerve.

Question 2

Which of the following best describes the function of the phrenic nerve, and from which plexus does it arise?

Accepted Answer

It innervates the diaphragm and arises from the cervical plexus.

Question 3

A reflex arc typically follows which correct sequence of structures?

Accepted Answer

Receptor $\rightarrow$ Sensory neuron $\rightarrow$ Integration center $\rightarrow$ Motor neuron $\rightarrow$ Effector

Question 4

Which of the following best distinguishes between exteroreceptors and interoreceptors?

Accepted Answer

Exteroreceptors detect stimuli from outside the body, while interoreceptors detect stimuli from within the body.

Question 5

A patient is unable to move their right leg but can still feel touch and pain in that leg. Which spinal nerve root is most likely damaged?

Accepted Answer

The ventral (anterior) root, which contains motor neurons.

Question 6

Which of the following cranial nerves is correctly matched with its primary function?

Accepted Answer

Optic nerve (II): vision (sensory)

Question 7

Which of the following best describes a mixed nerve?

Accepted Answer

A nerve that contains both sensory and motor fibers.

Question 8

The fight-or-flight response is primarily mediated by which division of the autonomic nervous system?

Accepted Answer

Sympathetic division

Question 9

Which of the following is NOT a correct pairing of a nerve and its associated plexus?

Accepted Answer

Sciatic nerve – cervical plexus

Question 10

A patient has difficulty breathing due to damage to a nerve that arises from the cervical plexus. Which nerve is most likely affected?

Accepted Answer

Phrenic nerve

Question 11

Which connective tissue layer directly surrounds individual axons within a nerve?

Accepted Answer

Endoneurium

Question 12

Which of the following best describes a plexus in the peripheral nervous system?

Accepted Answer

A network of intersecting nerves formed by the ventral rami of spinal nerves.

Question 13

A person accidentally touches a hot stove and immediately withdraws their hand. Which type of receptor and which type of reflex are primarily involved?

Accepted Answer

Exteroreceptor; spinal reflex

Question 14

Which of the following is a correct statement about the organization of the peripheral nervous system?

Accepted Answer

The PNS is divided into sensory (afferent) and motor (efferent) divisions.

Question 15

Which of the following best describes the function of proprioceptors?

Accepted Answer

They detect the position and movement of body parts.

Question 16

A patient is unable to feel pain or temperature on the left side of their face, but can still move their facial muscles. Which cranial nerve is most likely affected?

Accepted Answer

Trigeminal nerve (V)

Question 17

Which of the following best describes the difference between the somatic and autonomic divisions of the motor (efferent) system?

Accepted Answer

The somatic division controls voluntary skeletal muscles, while the autonomic division controls involuntary smooth and cardiac muscles.

Question 18

Which of the following is an example of a chemoreceptor in the human body?

Accepted Answer

Olfactory receptors in the nasal cavity detecting odor molecules.

Question 19

A patient has lost the ability to extend their knee. Which nerve and plexus are most likely involved?

Accepted Answer

Femoral nerve; lumbar plexus

Question 20

Which of the following best explains why damage to a single spinal nerve may not result in complete loss of function in a limb?

Accepted Answer

Because nerve fibers from several spinal nerves intermingle in plexuses, providing redundancy.

Peripheral Nervous System: Structure, Function, and Clinical Significance

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