Lecture 9: Brainstem Intro

Question 1

What are the 3 major divisions of the brainstem?

Answer 1

midbrain, pons and medulla

Question 2

Describe the anatomical features of the midbrain?

Answer 2

ventral: cerebral peduncle and CNIII, dorsal: two pairs of colliculi as well as CIV; cerebral aqueduct travels through the middle

Question 3

Describe the anatomical features of the pons.

Answer 3

ventral: bulbous basal pons as well as CN V, VII, VI and VIII, dorsally: creates the floor of the 4th ventricle (contains many pathways to the cerebellum)

Question 4

Describe the anatomical features of the medulla.

Answer 4

ventral: corticospinal axon pyramids, laterally the olive and CN XII, dorsal CN IX,X and XI

Question 5

What are the three “regions” of the brainstem from ventral to dorsal?

Answer 5

basal, tementum, tectum

Question 6

What are the 3 brainstem functions?

Answer 6

conduit of axon pathways, cranial nerve nuclei and integration by reticular systems

Question 7

Name the big 4 ascending/descending pathways.

Answer 7

dorsal Spinocerebellar, Dorsal Column, Corticospinal (lateral) and spinothalamic (anterior lateral)

Question 8

Which of the big four decussate in the brainstem?

Answer 8

dorsal column cells decussate in the caudal medulla; the corticospinal tract is part of the pyramidal decussation at the very end of the spinal cord.

Question 9

Where does the spinocerebellar tract exit the brainstem?

Answer 9

just below the pons

Question 10

Name the two regions of the brainstem that are involved in integrative function and the part brainstem in which they reside.

Answer 10

periacqueductal gray (PAG) in the midbrain around the aqueduct, the reticular formation in the rostral medulla (ascending pathway regulates state of arousal) , reticulopsinal pathway (descending pathways: motor control and pattern generators, respiratory centers, pain modulation and autonomic reflex circuitry)

Question 11

CN I: state name and type of fiber

Answer 11

olfactory, only special sensory

Question 12

CN II : state name and type of fiber

Answer 12

optic, only special sensory

Question 13

CN III: state name and type of fiber

Answer 13

oculomotor; autonomic and somatomotor

Question 14

CN IV:state name and type of fiber

Answer 14

trochlear: somatomotor

Question 15

CN V state name and type of fiber

Answer 15

trigeminal; somatosensory and branchiomotor

Question 16

CN VI state name and type of fiber

Answer 16

abducens: somatomotor

Question 17

CN VII: state name and type of fiber

Answer 17

facial: somatosensory, viscerosensory, autonomic and branchiomotor

Question 18

CN VIII: state name and type of fiber

Answer 18

vestibulocochlear: special sensory

Question 19

CN IX: :state name and type of fiber

Answer 19

glossopharyngeal: somatosensory, viscerosensory, autonomic and branchio motor

Question 20

CN X:state name and type of fiber

Answer 20

vagus: somatosensory, viscerosensory, autonomic and branchio motor

Question 21

CN XI: state the name and fiber type

Answer 21

(spinal) accessory: branchiomotor

Question 22

CN XII: state the name and fiber type

Answer 22

hypoglossal: somatomotor