Question 1

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

Accepted Answer

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

Question 2

A patient presents with loss of pain and temperature sensation in a localized area of skin. Which type of sensory receptor is most likely damaged?

Accepted Answer

Nociceptors

Question 3

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

Accepted Answer

PNS axons can regenerate if the soma is intact and the damage is not severe.

Question 4

Which cranial nerve is responsible for facial expression and taste sensation from the anterior two-thirds of the tongue?

Accepted Answer

Facial nerve (CN VII)

Question 5

A patient with carpal tunnel syndrome has difficulty with the pincer grasp (opposed thumb and index finger). Which nerve is most likely affected?

Accepted Answer

Median nerve

Question 6

Which of the following best explains why referred pain occurs, such as left arm pain during a heart attack?

Accepted Answer

Visceral and somatic pain fibers travel along the same nerves, causing the brain to misinterpret the source of the pain.

Question 7

Which of the following is a function of the phrenic nerve?

Accepted Answer

Provides motor and sensory innervation to the diaphragm

Question 8

Which of the following best describes the process of adaptation in sensory receptors?

Accepted Answer

A decrease in receptor sensitivity in the presence of a constant stimulus

Question 9

Which of the following equations best represents the relationship between stimulus intensity and action potential frequency in sensory neurons?

Accepted Answer

$$f = k \cdot I$$

Question 10

A patient is unable to extend their wrist after improper use of crutches. Which nerve is most likely compressed?

Accepted Answer

Radial nerve

Question 11

Which of the following is a characteristic of phasic receptors?

Accepted Answer

They adapt quickly to a constant stimulus and signal changes in stimulus intensity.

Question 12

Which of the following is the correct order of the five basic components of a reflex arc?

Accepted Answer

Receptor, sensory neuron, integration center, motor neuron, effector

Question 13

Which of the following best describes the function of muscle spindles?

Accepted Answer

Detect changes in muscle length and initiate stretch reflexes

Question 14

A patient presents with hyperextended little and ring fingers and difficulty making a fist. Which nerve is most likely damaged?

Accepted Answer

Ulnar nerve

Question 15

Which of the following is TRUE about the Babinski sign?

Accepted Answer

It is normal in infants under one year old but indicates upper motor neuron damage in adults.

Question 16

Which of the following best explains why damage to a single spinal nerve rarely causes complete numbness in a dermatome?

Accepted Answer

Most dermatomes overlap, so adjacent nerves can compensate for the loss.

Question 17

Which of the following is a function of the cerebellum in motor control?

Accepted Answer

Fine-tunes motor activity by acting on motor pathways through the brain stem and motor cortex

Question 18

Which of the following best describes the crossed-extensor reflex?

Accepted Answer

It involves withdrawal of a limb on one side and extension of the opposite limb to maintain balance.

Question 19

Which equation best represents the threshold condition for generating an action potential in a sensory neuron?

Accepted Answer

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

Question 20

Which of the following is a real-life application of capsaicin cream in clinical practice?

Accepted Answer

It desensitizes nociceptors, reducing the transmission of pain signals in conditions like neuropathies and shingles.

Peripheral Nervous System: Structure, Function, and Clinical Relevance

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