Chapter 17: The Nervous System

Question 1

Gray matter consists of…

Answer 1

…aggregations of neuronal cell bodies.

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Question 2

White matter consists of…

Answer 2

…neuronal axons that are coated with myelin.

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Question 3

The internal capsule is…

Answer 3

…a white-matter structure where myelinated fibers converge from all parts of the cerebral cortex and descend into the brainstem.
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Question 4

The spinal cord is thickest in the ________ segment, which contains nerve tracts to both the….

Answer 4

cervical
upper and lower extremities
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Question 5

The spinal cord is divided into the following segments:

Answer 5

cervical, from C1 to C8
thoracic, from T1 to T12
lumbar from L1 to L5
sacral from S1 to S5
coccygeal
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Question 6

To avoid injury to the spinal cord, most lumbar punctures are performed at the…

Answer 6

…L3-4 or L4-5 vertebral interspaces

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Question 7

Each nerve has an anterior (_______) root containing _____ fibers, and a posterior (______) root containing _______ fibers.

Answer 7

ventral; motor
dorsal; sensory
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Question 8

What is cranial nerve I and what is its function?

Answer 8

Olfactory - sense of smell

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Question 9

What is cranial nerve II and what is its function?

Answer 9

Optic - vision

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Question 10

What is cranial nerve III and what is its function?

Answer 10

Oculomotor - pupillary constriction, opening the eye (lid elevation), and most extraocular movements
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Question 11

What is cranial nerve IV and what is its function?

Answer 11

Trochlear - downward, internal rotation of the eye

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Question 12

What is cranial nerve V and what is its function?

Answer 12

Trigeminal

• Motor - temporal and masseter muscles (jaw clenching), lateral pterygoids (lateral jaw movement)
• Sensory - facial. The nerve has three divisions: (1) ophthalmic, (2) maxillary, and (3) mandibular
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Question 13

What is cranial nerve VI and what is its function?

Answer 13

Abducens - lateral deviation of the eye

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Question 14

What is cranial nerve VII and what is its function?

Answer 14

Facial

• Motor - facial movements, including those of facial expression, closing the eye, and closing the mouth
• Sensory - taste for salty, sweet, sour, and bitter substances on the anterior two-thirds of the tongue
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Question 15

What is cranial nerve VIII and what is its function?

Answer 15

Acoustic - hearing (cochlear division) and balance (vestibular division)
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Question 16

What is cranial nerve IX and what is its function?

Answer 16

Glossopharyngeal

• Motor - pharynx
• Sensory - posterior portions of the eardrum and ear canal, the pharynx, and the posterior tongue, including taste (salty, sweet, sour, bitter)
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Question 17

What is cranial nerve X and what is its function?

Answer 17

Vagus

• Motor - palate, pharynx, and larynx
• Sensory - pharynx and larynx
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Question 18

What is cranial nerve XI and what is its function?

Answer 18

Spinal accessory - motor - the sternomastoid and upper portion of the trapezius
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Question 19

What is cranial nerve XII and what is its function?

Answer 19

Hypoglossal - motor - tongue

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