Flashcards in Chapter 17: The Nervous System Deck (19)
Gray matter consists of...
...aggregations of neuronal cell bodies.
White matter consists of...
...neuronal axons that are coated with myelin.
The internal capsule is...
...a white-matter structure where myelinated fibers converge from all parts of the cerebral cortex and descend into the brainstem.
The spinal cord is thickest in the ________ segment, which contains nerve tracts to both the....
upper and lower extremities
The spinal cord is divided into the following segments:
cervical, from C1 to C8
thoracic, from T1 to T12
lumbar from L1 to L5
sacral from S1 to S5
To avoid injury to the spinal cord, most lumbar punctures are performed at the...
...L3-4 or L4-5 vertebral interspaces
Each nerve has an anterior (_______) root containing _____ fibers, and a posterior (______) root containing _______ fibers.
What is cranial nerve I and what is its function?
Olfactory - sense of smell
What is cranial nerve II and what is its function?
Optic - vision
What is cranial nerve III and what is its function?
Oculomotor - pupillary constriction, opening the eye (lid elevation), and most extraocular movements
What is cranial nerve IV and what is its function?
Trochlear - downward, internal rotation of the eye
What is cranial nerve V and what is its function?
- 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
What is cranial nerve VI and what is its function?
Abducens - lateral deviation of the eye
What is cranial nerve VII and what is its function?
-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
What is cranial nerve VIII and what is its function?
Acoustic - hearing (cochlear division) and balance (vestibular division)
What is cranial nerve IX and what is its function?
-Motor - pharynx
-Sensory - posterior portions of the eardrum and ear canal, the pharynx, and the posterior tongue, including taste (salty, sweet, sour, bitter)
What is cranial nerve X and what is its function?
-Motor - palate, pharynx, and larynx
-Sensory - pharynx and larynx
What is cranial nerve XI and what is its function?
Spinal accessory - motor - the sternomastoid and upper portion of the trapezius