Chapter 12 Final Exam

Which of the following reflexes involves a contralateral reflex arc?

crossed extensor reflex

A typical spinal cord has how many pairs of spinal nerves, and where does the spinal cord end?

31 pairs; lumbar vertebra 1 or 2

What is a reflex?

A reflex is a rapid, automatic response triggered by specific stimuli

Jim was in a car accident and suffered damage to the posterior ramus of several spinal nerves in his lumbar region. What problems might he experience as a result?

All of the listed responses are correct

When does the activation of a motor neuron occur in a stretch reflex?

after information processing in the CNS

Define gray matter in the spinal cord.

It contains the cell bodies of neurons, neuroglia, and unmyelinated axons, and it surrounds the narrow central canal.

What structure contains the cell bodies of sensory neurons?

posterior root ganglion

Sweat glands receive instructions through the anterior and posterior rami of spinal nerves. The neurons carrying these messages are _____ motor fibers, and their cell bodies are found in the __________.

visceral; sympathetic ganglion

Which is correct regarding the spinal cord?

The adult spinal cord ends between vertebrae L1 and L2.

Which of the following correctly describes a difference between the gray and white rami communicantes of a spinal nerve?

The white ramus contains myelinated fibers, and the gray ramus does not.

What is the function of denticulate ligaments?

They prevent lateral movement of the spinal cord.

The white matter of the spinal cord contains

bundles of axons with common origins, destinations, and functions.

The dorsal and ventral roots of spinal segments L2 to S5 and the filum terminale together form a complex called the __________.

cauda equina

Which is the innermost connective tissue layer of the spinal nerve that surrounds each axon?

endoneurium

Enlargements of the spinal cord occur

in those spinal segments that control the limbs.

There are five steps in the typical reflex arc. Which of the following best describes the activity of the third step?

information processing within the CNS