Label the anatomical structures of the spinal cord in the following figure.

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a. __

b. __

c __

d. __

e. __

f __

g. __

h. __

i ___

The anterior roots of each spinal segment

(a) Bring sensory information into the spinal cord

(b) Control peripheral effectors

(c) Contain the axons of somatic motor and visceral motor neurons

(d) Do both b and c

Spinal nerves are called mixed nerves because they

(a) Contain sensory and motor fibers

(b) Exit at intervertebral foramina

(c) Are associated with a pair of spinal ganglia

(d) Are associated with posterior and anterior roots

The adult spinal cord extends only to:

(a) The coccyx

(b) The sacrum

(c) The third or fourth lumbar vertebra

(d) The first or second lumbar vertebra

(e) The last thoracic vertebra

Which of the following statements is false concerning the gray matter of the spinal cord?

(a) It is located in the interior of the spinal cord around the central canal.

(b) It functions in processing neural information.

(c) It is primarily involved in relaying information to the brain.

(d) It contains motor neurons.

(e) It is divided into regions called horns.

The following are the steps involved in a neural reflex.

1. Activation of a sensory neuron

2. Activation of a motor neuron

3. Response by an effector

4. Arrival of a stimulus and activation of a receptor

5. Information processing

The proper sequence of these steps is

(a) 1, 3, 4, 5, 2

(b) 4, 5, 3, 1, 2

(c) 4, 1, 5, 2, 3

(d) 4, 3, 1, 5, 2

(e) 3, 1, 4, 5, 2

A sensory region monitored by the posterior rami of a single spinal segment is

(a) A ganglion

(b) A fascicle

(c) A dermatome

(d) A ramus

The major nerve of the cervical plexus that innervates the diaphragm is the

(a) Median nerve

(b) Axillary nerve

(c) Phrenic nerve

(d) Common fibular nerve

The genitofemoral, femoral, and lateral femoral cutaneous nerves are major nerves of the

(a) Lumbar plexus

(b) Sacral plexus

(c) Brachial plexus

(d) Cervical plexus

The synapsing of several neurons on the same postsynaptic neuron is called

(a) Serial processing

(b) Reverberation

(c) Divergence

(d) Convergence

The reflexes that control the most rapid, stereotyped motor responses to stimuli are

(a) Monosynaptic reflexes

(b) Polysynaptic reflexes

(c) Tendon reflexes

(d) Extensor reflexes

The contraction of flexor muscles and the relaxation of extensor muscles illustrate the principle of

(a) Reverberating circuitry

(b) Generalized facilitation

(c) Reciprocal inhibition

(d) Reinforcement

Reflex arcs in which the sensory stimulus and the motor response occur on the same side of the body are:

(a) Contralateral

(b) Paraesthetic

c) Ipsilateral

(d) Monosynaptic.

Proceeding deep from the most superficial structure, number the following in the correct sequence:

(a) _____ walls of vertebral canal

(b) _____ dura mater

(c) _____ subdural space

(d) _____ epidural space

(e) _____ pia mater

(f) _____ arachnoid membrane

(g) _____ subarachnoid space

(h) _____ spinal cord

Explain the anatomical significance of the fact that spinal cord growth stops at age 4.

List, in sequence, the five steps involved in a neural reflex.

Polysynaptic reflexes can produce far more complicated responses than can monosynaptic reflexes because

(a) The response time is quicker.

(b) The response is initiated by highly sensitive receptors.

(c) Motor neurons carry impulses at a faster rate than do sensory neurons.

(d) The interneurons involved can control several muscle groups.

Why do cervical nerves outnumber cervical vertebrae?

If the anterior horns of the spinal cord were damaged, what type of control would be affected?

What five characteristics are common to all polysynaptic reflexes?

Predict the effects on the body of a spinal cord transection at segment C₇. How would these effects differ from those of a spinal cord transection at segment T₁₀?

Ascending tracts

(a) Carry sensory information to the brain,

(b) Carry motor information to the brain

(c) Carry sensory information from the brain

(d) Carry motor information from the brain

(e) Connect perceptive areas with the brain

What effect does the stimulation of a sensory neuron that innervates an intrafusal muscle fiber have on muscle tone?

Mary complains that when she wakes up in the morning, her thumb and forefinger are always “asleep.” She mentions this condition to her physician, who asks Mary whether she sleeps with her wrists flexed. She replies that she does. The physician tells Mary that sleeping in that position may compress a portion of one of her peripheral nerves, producing her symptoms. Which nerve is involved?

The improper use of crutches can produce a condition known as 'crutch paralysis,' characterized by a lack of response by the extensor muscles of the arm, and a condition known as 'wrist drop,' consisting of an inability to extend the fingers and wrist. Which nerve is involved?

Bowel and urinary bladder control involve spinal reflex arcs that are located in the sacral region of the spinal cord. In both instances, two sphincter muscles—an inner sphincter of smooth muscle and an outer sphincter of skeletal muscle—control the passage of wastes (feces and urine) out of the body. How would a transection of the spinal cord at the L₁ segment level affect an individual's bowel and bladder control?

Karen falls down a flight of stairs and suffers lumbar and sacral spinal cord damage due to hyperextension of her back. The injury resulted in edema around the central canal that compressed the anterior horn of the lumbar region. What signs would you expect to observe as a result of this injury?