PONS Flashcards
What does the lateral lemniscus carry?
Auditory information
What does the superior olivary nucleus do?
reduces back ground noise by inhibiting the hair cells in the otolithic membrane, involved in sound localization
What muscle does abducens innervate?
IL lateral rectus
What can cause a lesion to the abducens nerve?
aneurysms of the PICA or basilar arteries or cerebellar tumors.
What is caused by lesions to the abducens nerve?
Medial strabismus, strabisus, esotropia, lateral gaze paralysis, internuclear ophthalomoplegia
What is strabismus?
inability to direct both eyes to the same target, results in diplopia, compensation by turning head in the direction of the target.
What is internuclear ophthalomoplegia?
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.
Where are internuclear neurons?
axons are between the abducens and occulomotor nuclei.
Somatic motor of facial nerve
innervate muscles of the face (facial expression)
LMN of facial nerve
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.
UMN lesion of facial nerve
CL face muscle paralysis, can wrinkle forehead and clsoe eye d/t bilateral innervation
Visceral motor of Facial nerve
innervates lacrimal, sublingual and submandibular glands.
Special sensory for taste for facial nerve
anterior 2/3 of tongue
Chief sensory nucleus (CN V)
2 point discrimination, vibration, conscious proprioception, fine discriminatory touch.
Motor nucleus of CN V
muscles of mastication
Trigeminal nerve
3 divisions - opthalamic, maxillary, mandibular
Mandibular division of trigeminal
both motor and sensory -
sensory = inferior alveolar, lingual (anterior 2/3 tongue)
somatic = muscles of mastication (masseter, temporalis, lateral pterygoid, medial pterygoid.
LMN lesions of trigeminal nerve
vascular dysfunction in pons, trauma, tumor. difficulty chewing, atrophy/weakness of chewing muscles itsilateral to side of weakness, decreased jaw reflex.
Locus ceruleus
(upper pons)
Ascending - cortex –> norepi –> attention/arousal
Descending - raphe tract –> transmits pain, “emotional motor system”
Superior colliculus
voluntary/involuntary movement of the eyes/head
Red nucleus
relay station b/t cerebellum and thalamus
Occulomotor nerve somatic motor
IO, IR, MR, SR, LPS
Occulomotor nerve visceral motor
pupillary constrictors, cilliary muscles
Edinger Westphal nucleus
origin of pregganlionic parasympathetic neurons in ciliary ganglion. Post ganglionic innervate pupillary contrictors and ciliary muscles
Ipsilateral ophthalomoplegia
lesion of CN III unopposed LR –> dilated pupil (parasympathetic constricting nerve damaged), ptosis (no levator palpebrae)
Webers syndrome
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)
Inferior colliculus
Integrates auditory info from both ears and detects location of sound.
