Exam 5 Flashcards
Lateral lemniscus
Axons from CL dorsal/ventral cochlear nuclei
Transmits auditory information
Superior olivary nucleus
Sends axons to Organ of Corti to inhibit hair cells to reduce background noise. Involved in sound localization
Three parts of basalar bonx
Corticospinal tract
Corticobulbar tract
Pontine nuclei
Corneal reflex tests which nerves
CN V and VII
LMN Lesion of facial nerve
Total paralysis on IL side of face: Unable to close eyelid tightly Unable to wrinkle forehead Sensation intact to pinprick (CN V) Could have lack of taste of hyeracusis
UMN lesion of Facial nerve
Paralysis of CL facial muscles but can wrinkle forehead and possible weakly close eyelid because of bilateral innervation
Two facial muscles that have bilateral innervation
Frontalis
Orbicularis oris
Ramsey Hunt Syndrome
Compression and damage to both CN VII and VIII as they travel through acoustic meatus
Bell’s Palsy and balance problems
Visceral motor (parasympathetic) actions of facial nerve
Innervates lacrimal gland - washes away foreign substances and keeps eye moist
Submandibular and sublingual glands - moistens food and assist moving food toward oropharynx
Ageusia
Loss of taste sensation
Hypogeusia
Decreased taste sensation
Dysgeusia
Abnormal sensation of taste
Function of the abducens nerve
Innervates the IL lateral rectus muscle (abducts the eye)
Medial strabismus
Inability to direct both eyes on the same target due to inability to laterally rotate the eye
Esotropia
Medial deviation of IL eye and inability to laterally rotate the eye
Medial longitudinal fasciculus
Contains axons innervating CL medial recti
Inernuclear Opthalmoplegia
Inability to medially rotate the eye during gaze to opposite side
Somatic motor nerves of V3 distribution of trigeminal nerve
Medial and lateral pterygoid
Temporalis
Masseter
Sensory branches of V3 distribution of trigeminal nerve
Mandibular teeth and tongue sensory branches
Inferior alveolar nerves
Lingual nerve
Mesencephalic Nucleus
Located from mid-pons to superior colliculus of the midbrain
Contains cell bodies of peripheral processes which transmit proprioceptive information from muscles of mastication
Masseter
elevates mandible
Temporalis
Elevates and retracts mandible
Lateral pterygoid
bilateral contraction: protrusion and depression of mandible
Unilateral contraction: contralateral side movement of mandible
Medial pterygoid
Assists with elevation and protrusion
LMN Lesion of trigeminal nerve
Difficulty chewing
Atrophy/weakness of muscles of mastication
Jaw deviates to one side with mouth opening (deviates IL to side of lesion due to lateral pterygoid wekaness)
UMN lesion of trigeminal nerve
minimal effect on masticatory muscles due to bilateral innervation
Ascending axons of locus ceruleus
Release of norepinephrine to stimulate attention/arousal
Descending axons of locus ceruleus
Pain inhibition and part of emotional motor system (slower movements with fear & anxiety)
Inferior colliculus
Integrates auditory information from both ears and detects location of sound
Function of trochelar nerve
Innervates the superior oblique muscle which adducts and intorts the eye
Important for looking down at ground and looking down to read
Rubrospinal tract
neck and UE flexor muscles
Relay station between cerebellum and thalamus
Superior colliculus
Voluntary/involuntary movement of the eye/head
Somatic motor innervation of oculomotor nerve
Inferior oblique Inferior rectus Medial rectus Superior rectus (CL) Levator palpeabrae superioris (CL)
Visceral motor innervation of oculomotor nerve
Ciliary muscles (increase or decrease diameter of lens) Pupillary constrictors
Accommodation Reflex
Pupils constrict
Eyes adduct
Lens becomes more convex
Lesion of CN III nucleus or nerve
Unopposed lateral rectus
Mydriasis (dilated pupil)
Ptosis (decreased innervation of LPS)
Weber’s syndrome
Dilated pupil
Ptosis
Eye deviates downward (SO) or laterally (LR)
Contralateral UMN paralysis because of cerebral penduncles
Decorticate rigidity
Lesion above red nucleus
Uninhibited rubrospinal tract and lateral vestibulospinal tract
Flexion of UE and extension of LE
Worse prognosis
Decerbrate rigidity
Lesion between red nucleus and lateral vestibular nucleus
Extension of extremities/trunk
Uninhibited extension biased lateral vestibulospinal tract dominates inhibited rubrospinal tract
Better prognosis
4 D’s of Brainstem
Dysphagia - difficulty swallowing
Dysarthria- difficulty articulating
Diplopia - double vision
Dysmetria - unable to stop a movement at a certain point
Reticular Formation
Consists of axons/dendrites and clusters of nerve cell bodies (ganglia) dispersed amongst axon/dendrites
Raphe magnus nucleus
Serotonin
Ascending tracts - induce sleep
Descending tracts - inhibit pain (raphe spinal tract)
Central group nuclei
Involved in alertness and arousal
Can arouse or wakeup a person
Ventral tegmental area
cells produce dopamine to cerebral areas important in motivation and decision making, as well as feelings of pleasure and reward
