Q: Which equation best represents the direction of impulse conduction in sensory (afferent) and motor (efferent) tracts of the spinal cord?

$$\text{Sensory (afferent) tracts}: \text{Periphery} \rightarrow \text{CNS}$$ $$\text{Motor (efferent) tracts}: \text{CNS} \rightarrow \text{Periphery}$$

Q: Which equation best describes the relationship between the number of spinal nerves and the regions of the spinal cord?

$$\text{Number of spinal nerves} = 8 \text{ cervical} + 12 \text{ thoracic} + 5 \text{ lumbar} + 5 \text{ sacral} + 1 \text{ coccygeal} = 31$$

Question 1

Which structure marks the inferior end of the spinal cord, and what is its clinical significance?

Accepted Answer

The cauda equina; it is a bundle of spinal nerves that can be affected in cauda equina syndrome, leading to loss of bladder and bowel control.

Question 2

A patient presents with loss of sensation in the right hand and inability to move the right arm. Which part of the spinal cord is most likely damaged?

Accepted Answer

Both the dorsal and ventral horns of gray matter on the right side.

Question 3

Which equation best represents the direction of impulse conduction in sensory (afferent) and motor (efferent) tracts of the spinal cord?

Accepted Answer

$$	ext{Sensory (afferent) tracts}: 	ext{Periphery} ightarrow 	ext{CNS}$$
$$	ext{Motor (efferent) tracts}: 	ext{CNS} ightarrow 	ext{Periphery}$$

Question 4

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

Accepted Answer

It contains cell bodies of sensory neurons transmitting impulses toward the CNS.

Question 5

A patient suffers a traumatic injury that severs the ventral root of a spinal nerve. What deficit would you expect?

Accepted Answer

Loss of voluntary motor function in the muscles served by that nerve.

Question 6

Which cranial nerve is responsible for both facial expression and taste, and what type of nerve is it?

Accepted Answer

Facial nerve (VII); it is a mixed nerve.

Question 7

Which spinal nerve plexus is responsible for innervating the diaphragm, and what is the clinical consequence of injury to this plexus?

Accepted Answer

Cervical plexus; injury can result in respiratory paralysis.

Question 8

Which equation best describes the relationship between the number of spinal nerves and the regions of the spinal cord?

Accepted Answer

$$	ext{Number of spinal nerves} = 8 	ext{ cervical} + 12 	ext{ thoracic} + 5 	ext{ lumbar} + 5 	ext{ sacral} + 1 	ext{ coccygeal} = 31$$

Question 9

A patient is unable to extend their wrist and has loss of sensation on the posterior forearm. Which nerve and plexus are most likely affected?

Accepted Answer

Radial nerve from the brachial plexus.

Question 10

Which of the following best explains the difference between the somatic and autonomic nervous systems?

Accepted Answer

Somatic motor neurons originate in the CNS and directly innervate skeletal muscle; autonomic motor neurons use a two-neuron chain to innervate smooth muscle, cardiac muscle, and glands.

Question 11

Which division of the autonomic nervous system is responsible for the 'fight or flight' response, and what are its primary effects on the digestive system?

Accepted Answer

Sympathetic division; it decreases digestive activity and constricts digestive system sphincters.

Question 12

Which cranial nerve is the only one to extend beyond the head and neck into the thoracic and abdominal cavities, and what is its main function?

Accepted Answer

Vagus nerve (X); it provides parasympathetic innervation to thoracic and abdominal organs.

Question 13

A patient presents with 'foot drop' and inability to dorsiflex the foot. Which nerve and plexus are most likely involved?

Accepted Answer

Common fibular (peroneal) nerve from the sacral plexus.

Question 14

Which equation best represents the relationship between the sympathetic and parasympathetic divisions in terms of their effects on heart rate?

Accepted Answer

$$	ext{Sympathetic}: \uparrow 	ext{Heart Rate}$$
$$	ext{Parasympathetic}: \downarrow 	ext{Heart Rate}$$

Question 15

Which of the following is a real-life example of sympathetic nervous system activation?

Accepted Answer

A person running from a dangerous animal experiences increased heart rate, dilated bronchioles, and decreased digestive activity.

Question 16

Which nerve is most likely damaged if a patient cannot adduct their thigh and has loss of sensation on the medial thigh?

Accepted Answer

Obturator nerve from the lumbar plexus.

Question 17

Which of the following best describes the role of the pia mater in the spinal cord?

Accepted Answer

It is the innermost meningeal layer that closely adheres to the surface of the spinal cord, providing protection and support.

Question 18

A patient presents with 'claw hand' and inability to spread their fingers. Which nerve and plexus are most likely affected?

Accepted Answer

Ulnar nerve from the brachial plexus.

Chapter 7: Nervous System – Spinal Cord and Peripheral Nervous System

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