PONS

Question 1

What does the lateral lemniscus carry?

Answer 1

Auditory information

Question 2

What does the superior olivary nucleus do?

Answer 2

reduces back ground noise by inhibiting the hair cells in the otolithic membrane, involved in sound localization

Question 3

What muscle does abducens innervate?

Answer 3

IL lateral rectus

Question 4

What can cause a lesion to the abducens nerve?

Answer 4

aneurysms of the PICA or basilar arteries or cerebellar tumors.

Question 5

What is caused by lesions to the abducens nerve?

Answer 5

Medial strabismus, strabisus, esotropia, lateral gaze paralysis, internuclear ophthalomoplegia

Question 6

What is strabismus?

Answer 6

inability to direct both eyes to the same target, results in diplopia, compensation by turning head in the direction of the target.

Question 7

What is internuclear ophthalomoplegia?

Answer 7

damage to MLF which contains axons innervating CL medial recti. Inability to medially rotate the eye during gave to the opposite side. Convergence unaffected d/t higher centers.

Question 8

Where are internuclear neurons?

Answer 8

axons are between the abducens and occulomotor nuclei.

Question 9

Somatic motor of facial nerve

Answer 9

innervate muscles of the face (facial expression)

Question 10

LMN of facial nerve

Answer 10

Bell’s palsy: total paralysis on IL side of face. unable to close eyelid, wrinkle forehead, sensation intact. Lesion more superior = taste/hearing issues too.

Question 11

UMN lesion of facial nerve

Answer 11

CL face muscle paralysis, can wrinkle forehead and clsoe eye d/t bilateral innervation

Question 12

Visceral motor of Facial nerve

Answer 12

innervates lacrimal, sublingual and submandibular glands.

Question 13

Special sensory for taste for facial nerve

Answer 13

anterior 2/3 of tongue

Question 14

Chief sensory nucleus (CN V)

Answer 14

2 point discrimination, vibration, conscious proprioception, fine discriminatory touch.

Question 15

Motor nucleus of CN V

Answer 15

muscles of mastication

Question 16

Trigeminal nerve

Answer 16

3 divisions - opthalamic, maxillary, mandibular

Question 17

Mandibular division of trigeminal

Answer 17

both motor and sensory -
sensory = inferior alveolar, lingual (anterior 2/3 tongue)
somatic = muscles of mastication (masseter, temporalis, lateral pterygoid, medial pterygoid.

Question 18

LMN lesions of trigeminal nerve

Answer 18

vascular dysfunction in pons, trauma, tumor. difficulty chewing, atrophy/weakness of chewing muscles itsilateral to side of weakness, decreased jaw reflex.

Question 19

Locus ceruleus

Answer 19

(upper pons)
Ascending - cortex –> norepi –> attention/arousal
Descending - raphe tract –> transmits pain, “emotional motor system”

Question 20

Superior colliculus

Answer 20

voluntary/involuntary movement of the eyes/head

Question 21

Red nucleus

Answer 21

relay station b/t cerebellum and thalamus

Question 22

Occulomotor nerve somatic motor

Answer 22

IO, IR, MR, SR, LPS

Question 23

Occulomotor nerve visceral motor

Answer 23

pupillary constrictors, cilliary muscles

Question 24

Edinger Westphal nucleus

Answer 24

origin of pregganlionic parasympathetic neurons in ciliary ganglion. Post ganglionic innervate pupillary contrictors and ciliary muscles

Question 25

Ipsilateral ophthalomoplegia

Answer 25

lesion of CN III unopposed LR –> dilated pupil (parasympathetic constricting nerve damaged), ptosis (no levator palpebrae)

Question 26

Webers syndrome

Answer 26

vacular lesion (tumor affecting cerebral peduncle, occulomotor nerve. –> dilated pupil (lose CN III parasympa), ptosis (no levator palpebrae), eye deviates laterally (no medial rectus), CL UMN paralysis (cerebral peduncle has motor neurons go to CL side)

Question 27

Inferior colliculus

Answer 27

Integrates auditory info from both ears and detects location of sound.