caudal pons and PMJ

Question 1

pons two major divisions

Answer 1

dorsal portion, aka pontine tegmentum, and ventral basilar pons.

Question 2

dorsal portion of pons

Answer 2

rostral continuation of the medullary reticular formations, contains cranial nerve nuclei, and ascending sensory tracts.

Question 3

ventral basilar pons

Answer 3

cortically derived axons, corticobulbar and corticospinal, pontine nuclei, and projections from the pons to the cerebellum, middle cerebellar peduncle.

Question 4

pontomedullary jnxn

Answer 4

at the level of cranial nerve VIII vestibulocochlear-contains SSA fibers in the cochlear component, nuclei of CN 8 overlap pons and medulla.

Question 5

dorsal and ventral cochlear nuclei

Answer 5

autditory axons contact neurons in these nuclei in the brainstem.

Question 6

lateral lamniscus

Answer 6

primary ascending pathway formed from ventral and dorsal cochlear nuclei neurons.

Question 7

trapezoid body

Answer 7

region where crossing axons are seen in cross section

Question 8

brainstem sound processing nuclei

Answer 8

nucleus of trapezoid body, sup. olivary nucleus, nucleus of lat. lemn

Question 9

nucleus of trapezoid body

Answer 9

localization of sounds

Question 10

sup. olivary nuc

Answer 10

sound localization reflex, sound dempening via CN 7 and CN 5 tensor tympani

Question 11

nuc of lat lemn

Answer 11

sound localization, acoustic reflexes.

Question 12

axons of dorsal and ventral cochlear nuclei

Answer 12

collect primarily in the contralateral lateral lemn to ascend to inferior colliculus, medial geniculate body, cortex for conscious perception.

Question 13

lateral lemniscus

Answer 13

travels bilaterally with contralateral predominance, thus an ipsilateral lesion will not cause hearing loss unless it effects the nerve or nuclei.

Question 14

vestibular component

Answer 14

has 4 nuclei, superior, inferior, medial and lateral vestibular nuclei.

Question 15

central nuclear projections of vestibular nuclei

Answer 15

to cerebellum via juxtarestiform body, some direct floculonodular lobe and deep cerebellar nuclei

Question 16

juxtarestiform body

Answer 16

balance coordination.

Question 17

vestibular related pathways

Answer 17

occulomotor nuclei via medial long. fasciculus to the thalamus and thus to the cortex for conscious perception of equilibrium and orientation. the last via MLF projections as well.

Question 18

vestibular related pathways to SC

Answer 18

via lateral vestibulospiinal tract, from lateral vestibular nucleus
excitatory to extensor spinal motoneurons.

Question 19

medial vestibulospinal tract

Answer 19

via MLF, descends into the cord, inhibitory to neck and upper trunk muscles, contributes to head righting reflexes connected to vision.

Question 20

Facial nerve

Answer 20

CN 7- exits pons just anterior to CN 8 at the PMJ, provides motor innervation to muslces of facial expression, stylohyoid, posterior digastric, stapedius-sound dampening.

Question 21

facial colliculus

Answer 21

bump in the floor of the 4th ventricle, contains abducens and facial nerve fibers. where facial fibers wrap around CN 6 nucleus.

Question 22

facial nerve lesions

Answer 22

cortical or corticonuclear lesions might produce dysfunction of the face but not the forhead as the forhead is bilaterally inervated while the rest of the face is innervated contralaterally.

Question 23

CN 7 intermedius branch fnxn

Answer 23

parasympathetic innervation GVE, to lachrymal glands, mucous membranes of nose, hard and soft palate, and salivary glands.

Question 24

superior salivatory nucleus

Answer 24

GVE branch of intermedius branch of CN7 to the brainstem
axons transverse the geniculate ganglion to synapse in the pterygopalatine gang.
stymulate secretion from lacrymal and saliva glands.

Question 25

fnxn of parasympathetic CN7

Answer 25

emotional response,weeping, mouth watering

from limbic system and olfact. areas through hypthal, to brainstem via dorsal long. fasciculus.

Question 26

taste

Answer 26

CN 7 SVA anterior 2/3 of the tongue, hard and soft palates via geniculate ganglion.

Question 27

Solitary nucleus and tract

Answer 27

SVA of chorda tympani run from the geniculate ganglion, projects to the brainstem as part of nervus intermedius, enters solitary tract to synaps in sol. nucleus, nucleus sends info via central tegmental to thalamus then to cortex for conscious perception of taste.

Question 28

somatic sensation of CN7

Answer 28

GSA to skin of ear wall and tympanic membrane via geniculate ganglion.

Question 29

pathway of somatic CN7

Answer 29

enter brainstem via nervus intermedius and descend along spinal tract of V to synapse.

Question 30

abducens nerve

Answer 30

CN 6 purely motor inerevation to the ipsilateral lateral rectus muscle of the eye

Question 31

CN 6 interaction w oculomotor nucleus

Answer 31

through medial long. fascic. involved in conjugate eye movements.

Question 32

reticular formation

Answer 32

in the caudal pons, forms complex connections between CN nuclei for reflex and visceral fnxn.