Question 1

A physician must administer an anesthesia directly to the CNS via the vertebral column. How many layers of the meninges must be punctured to do so?

Accepted Answer

To administer anesthesia directly to the CNS via the vertebral column into the subarachnoid space, the needle must puncture two layers of the meninges: the dura mater and the arachnoid mater. The third layer, the pia mater, closely adheres to the surface of the brain and spinal cord and is not punctured in this procedure.

Question 2

If reciprocal innervation failed during a stretch reflex, the consequence might be that

Accepted Answer

Reciprocal innervation ensures that while one muscle contracts, its opposing muscle relaxes, allowing for smooth movement. If this mechanism fails, both the muscle and its antagonist might contract simultaneously, leading to diminished movement.

Question 3

In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to ________ and the hamstrings to ________.

Accepted Answer

The patellar tendon reflex arc is a stretch reflex that causes the quadriceps femoris muscle to contract in response to being stretched, while simultaneously causing the antagonistic muscles, the hamstrings, to relax. This coordinated response allows for the leg to kick forward without resistance from the hamstrings.

Question 4

Which of the following sensory functions involves neurons in the dorsal root ganglion?

Accepted Answer

The dorsal root ganglion contains the cell bodies of sensory neurons that bring information from the periphery to the spinal cord, including touch sensations.

Question 5

Which reflex shows the least synaptic delay?

Accepted Answer

The Golgi tendon reflex is a monosynaptic reflex, which involves only one synapse between the sensory neuron and the motor neuron, resulting in the least synaptic delay compared to polysynaptic reflexes that involve multiple synapses.

Question 6

The largest nerve in the body is the ________ nerve.

Accepted Answer

The answer of The largest nerve in the body is...

Question 7

You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little, but a reflex causes your head to rise. This is called the ________ reflex.

Accepted Answer

The reflex described is the stretch reflex, which occurs when muscle spindles are stretched and a rapid contraction is initiated to compensate, such as when your head starts to lower while nodding off and then suddenly jerks back up.

Question 8

Glen is complaining of abnormal sensations, such as cold or hot sensations, along his left hip and anterior thigh. His physician suggests that certain nerves may be compressed, causing these sensations. Which of the following are most likely affected?

Accepted Answer

The answer of Glen is complaining of abnormal sensations, such...

Question 9

A patient with no sensation in the left thumb would most likely have nerve damage of the ________ spinal nerve.

Accepted Answer

The C6 spinal nerve is responsible for sensation in the thumb area. Damage to this nerve would result in loss of sensation in the left thumb.

Question 10

Dennis has lost the ability to voluntarily raise his left arm due to damage to his spinal cord and associated nerves. Which of the following is a possible explanation for Dennis's symptom?

Accepted Answer

The ventral roots of the spinal cord carry motor information from the brain to the muscles, enabling voluntary movements. Damage to the ventral roots in the cervical region, which innervates the arms, would impair Dennis's ability to raise his arm.

Question 11

Cutaneous sensory distribution of a spinal nerve can be mapped as a ________.

Accepted Answer

The answer of Cutaneous sensory distribution of a spinal nerve...

Question 12

Which of the following is not a property of reflexes?

Accepted Answer

Reflexes are automatic responses to specific stimuli, meaning they always require a stimulus to occur. This is a fundamental aspect of what defines a reflex.

Question 13

Which of the following is not a function associated with the spinal cord?

Accepted Answer

The spinal cord's primary functions include mediating reflexes, conducting sensory information to the brain, and motor information from the brain down the cord, as well as coordinating muscle contractions for locomotion. However, protecting neurons is not a function of the spinal cord itself but rather a role of the vertebral column and the meninges.

Question 14

An abnormal patellar reflex indicates damage of the T10 - T12 spinal segments.

Accepted Answer

An abnormal patellar reflex indicates potential damage or issues with the L2-L4 spinal segments, not T10-T12. The patellar reflex tests the function of the femoral nerve, which originates from the lumbar spinal nerves L2-L4.

Question 15

Myelin is essentially the endoneurium of myelinated axons.

Accepted Answer

Myelin is a specialized membrane that wraps around the axons of neurons, providing insulation and increasing the speed of electrical impulses. The endoneurium is the innermost layer of connective tissue that surrounds individual nerve fibers, including both myelinated and unmyelinated axons. Therefore, myelin can be considered a specialized type of endoneurium that is specific to myelinated axons.

Question 16

The ________ is the basic functional unit of the nervous system and is capable of receiving a stimulus and producing a response.

Accepted Answer

The answer of The ________ is the basic functional unit...

Question 17

The cervical region of the spinal cord lacks associated autonomic nuclei. How will a cross section of the spinal cord in this region differ from a cross section of the thoracic region?

Accepted Answer

Lateral gray horns, which contain autonomic motor nuclei, are present in the thoracic and upper lumbar regions of the spinal cord but not in the cervical region.

Question 18

Which of the following would explain the loss of certain sensations from the skin of the posterior region of the upper limb?

Accepted Answer

Damage to one or more dorsal roots in the thoracic region of the spinal cord would result in the loss of certain sensations from the skin of the posterior region of the upper limb. This is because the dorsal roots are responsible for carrying sensory information from the skin to the spinal cord.

Question 19

Which of the following best differentiates between the endoneurium and myelin?

Accepted Answer

Endoneurium is a layer of delicate connective tissue that encases the individual nerve fibers, whereas myelin is a fatty substance formed by Schwann cells (in the peripheral nervous system) or oligodendrocytes (in the central nervous system) that wraps around nerve fibers to insulate them and speed up electrical impulses.

Question 20

Branches of the pudendal nerve are anesthetized during childbirth before the doctor performs a/an ________.

Accepted Answer

The answer of Branches of the pudendal nerve are anesthetized...

Quiz 12: Spinal Cord and Spinal Nerves