Auditory System Flashcards
face motor path
precentral gyrus (bilateral)
CBT
LMN in brainstem
target muscles
CBT lesions
contra lower face (all other bilateral)
cochlea pitches
high pitch at base (close)
low pitch at apex (far)
sensorineural hearing loss (conduction)
air > bone
conductive hearing loss (conduction)
bone > air
conductive hearing loss (examples)
wax buildup
gluing of ossicles
otits media
otosclerosis
sensorineural hearing loss (examples)
hair cells damaged
nerves damaged
(VIII)
hearing tests
weber
rinne
weber test
midline of skull
loss, same ear (conductive)
loss, opp ear (sensorineural)
rhine test
AC > BC normal
BC > AC conductive loss
cochlear nuc sections
dorsal (freq)
ventral (localization)
hearing path
hair cell cochlear nerve (spiral gang) cochlear nucleus (ipsi) thru trapezoid body sup olivary nuc (bi - pons) thru lat lemniscus (midbrain) inferior colliculus (midbrain) medial geniculate body (thalamus) sup temporal gyrus (cortex)
lesion above cochlear nuc
slight bilateral loss
cant localize sound
primary auditory cortex layout
under temporal
low freq, from apex = ant
high freq, from base = post
vestibular system fxns
minimize retinal image motion during mvmt
important for spatial orientation
important for posture/equilibrium
semicircular duct (mvmt)
angular acceleration
atricle/saccule (mvmt)
linear acceleration
gravity
vestibulo ocular reflex (VOR)
normal
turn head
endolymph goes opp direction
eyes go opp direction
hair cells in VOR
hair cells on side you turn toward: endolymph pushes along axis of hairs, increase firing of VIII
hair cells away from way you turn: endolymph pushes against axis of hairs, decrease firing of VIII
VOR path
head turn to side ipsi vestibular gang fire ipsi vestibular nuc contra abducens a. contra lat rectus b. ipsi occulomotor thru MLF, ipsi medial rectus
nystagmus direction
quick phase away from lesion
nystagmus mech
L lesion
R side acts stimulated –> push slowly to L
cortex corrects (put R quickly)
lesions –> nystagmus
vestibular nerve or nucleus
water in ear
cold (opp): cool in L, stim R, move eyes L slowly, move quickly R
warm: warm in R, stim R, move eyes L slowly, move quickly R
