brain stem and CN from chapter 10 in book

Question 1

spinal portion of accessory nerve XI originates where? how does it ascend?

Answer 1

gray matter of spinal cord from C2 to C5

exits lateral funiculus, ascends up lateral surface of the medulla

Question 2

what emerges from the dorsolateral sulcus of the medulla?

Answer 2

cranial portion of spinal accessory XI
vagus X
glossopharyngeal IX

Question 3

what emerges from the ventrolateral sulcus of the medulla?

Answer 3

hypoglossal nerve XII

Question 4

the olive lies between what 2 structures

Answer 4

ventrolateral sulcus and dorsolateral sulcus

Question 5

describe how the corticospinal tract crosses in the brain stem

Answer 5

corticospinal is voluntary movement
motor fibers emerge from caudal part of pons to form the pyramids on ventral surface of medulla. fibers then turn dorsally, decussate (motor deccusation of lower closed medulla) and move to lateral portion of the white matter of the spinal cord to form lateral corticospinal tract

Question 6

describe how the medial lemniscal system crosses in the brain stem

Answer 6

medial lemniscal=dorsal columns or fasciculus gracilis and fasciculus cuneatus (sensory)
dorsal columns end in medulla and synapse with gracile and cuneate nuclei. axons from nuclei migrate ventrally around center gray matter of the spinal cord (these migrating fibers are called internal arcuate fibers) this crossing is the sensory deccusation of the upper closed medulla. once the fibers cross they form the medial lemniscus and ascend up to the thalamus

Question 7

where are the spinothalamic tracts of the anteriolateral system located in the medulla

Answer 7

same as the spinal cord

laterally situated as they ascend towards thalamus

Question 8

where are the spinocerebellar fibers in the medulla?

Answer 8

just dorsal to the spinothalamic tracts of the anteriolateral system which are located in the lateral medulla
ascend to enter ICP bridge to the cerebellum

Question 9

alar plate gives rise to what type of nerve fibers that are located where?

Answer 9

alar=sensory

laterally

Question 10

basal plate gives rise to what type of nerve fibers that are located where?

Answer 10

motor

medially

Question 11

which of the 12 CN serve as components in the brain stem?

Answer 11

CN3-12

Question 12

SSA are what?

Answer 12

vision
hearing
balance

Question 13

SVA are what?

Answer 13

smell

taste

Question 14

SVE are what? come from what embryologic structure?

Answer 14

muscles of:
pharynx
larynx
jaw
facial expression
brachial arches

Question 15

pressure to what areas of the brain cause vomiting?

Answer 15

floor of the 4th ventricle from intracranial pressure

medulla from tumor or hemorhage