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auditory system
auditory system
47
Medical
Graduate
10/26/2011

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Term
ototoxins
Definition
used for tinnitus. many are antibiotics and affect obth hearing and balance
Term
ear anatomy slide 3
Definition
know pinna, typmanic membrane, area of the bones, cochlea (area of auditiory receptors)
Term
vestibulocochelar organ
Definition
has two sides, a vestibular sisd e with semischular canla nad cochlear for auditory system. inside the obney casei membranous chamber filled with endolymph which is high in potassium
Term
ochclear turning-
Definition
increases bass
Term
the ossiclesf unction
Definition
malleus incus , stapes. when tymapnci membrane hsakes, teh ossicels birbrate as wel li nahcain leer ssytem that gets transmitted to stapes which sensds it to oval window
Term
ossicile defiict
Definition
middle eardeficit. the ossicles amiplify the foce goign to the oval window and comepnsate for impedenace differnece beteween air fileld middle ear nad fluid filled inenr ear. INjury woudl result is huge weakenss in hearining
Term
otosclerosis
Definition
footplate of the stapes gets stuck
Term
Rinne test
Definition
you use tuning fokr hodl it by heear then hodl it agaisnt bone. By putting it agianst bone , you are leimianteing need for the bones. If patient can hear it one head louder htan ear ,the nit is a conductance problem. Sensory deafness if he cant hear either yb bone or by air
Term
Weber test
Definition
IF you hold tuning fork on both sides of head, shoudl be the same. IF they ehari t loduer on one side, ,either hte contralteral sidei sn ot funcitoning that well ,sensorily, or hte left side has doncution deafness os the enviromental noises are nto amiplified
Term
sound comes in vibrating basilar chamber bones vibrate, cause vibration in fluid fluid cant be compressed so moves on
Definition
Term
organization fo the scala
Definition
go past oval window , find scala medaie with endolympho oint is ,i t is surdouned by scala vestubli and scala tympani, vibrations caus efluid movement and this whoel hting moves.
Term
scala media relation to others
Definition
scala media seperaetd from scala vestibuli via reissner membrane. Seperated fro mscala tymapni via Basal membrane
Term
perilymph contained where
Definition
contained in the scala vestibuli adn tympani- tt is low in potasisum, the PD etween these scala nad the scala media is essential for hair cel mvoement
Term
cochlea
Definition
transforms luid waves in neural activity. We have hair cells located in the organ of corti, with outer and inenr rows. The outer rows are on the Tectorial membrane. When basilar membrane vibates stereocilia are bent , by shear forces otuside and by fluid movementsi nside
Term
rrows of hair cells
Definition
three rows of otuer hair cels , one row of inner
Term
auditiory hair cels anatomy
Definition
have clsuters of steroscilia on apical end. Thatehr tha nkinocillium ahve a basal body. Bendign towrads the basal body causes depolarization, bending awway hyperoplarization
Term
auditory hair cels bending effects
Definition
bending towards the basal body opens up mechanosensitive ion channels- specifocally potassium releaset o deplarize cells. Calcium the netners and then enurotransmitters are relased by primary sensory affernets conencted to it
Term
deflection effects of basilar membrane onto tenetorial membrane
Definition
tentorial membrane is stirrf, so whwen basillarm embrane deflectsu pwards doenst give, and the hair cels bend towards , basal body. when basilar membrane dips back down they hyeprpolarize. teh basialr membranes activity is sinusoidal however so get rarefactions and hyperpol-depol patern
Term
inner/ outerh air cell functions
Definition
inner hair cells- detect sound

outerh air cls- participate in amplicaiti noadn dampening of the osudn system.- due to contaction/elongation in synchrony with sound evoked potentials (due to protein prestin), genereating motor force
Term
haircells arei nenrvated by efferents
Definition
superior olviary nuclear compelx

outer hair cells: innervated contralaterraly, medial olivochoclear bundle,

innerh iar cells - ipsilaterally innverated by the later olivocochlear budle.
Term
volley principle
Definition
allow us to hear higher frequency than ourneurons would allow due to maximar rate of AP generation. In this principle , neurons iwl lnot fire eveyr time, but every thir d time ,with other neruosn fillign inf or them
Term
pahse locking
Definition
increse inf iring during depolarization, and decreasein hyperpolarization- so are able to phase lock, fire at the saem rate as teh sinusoidal stimulus
Term
cochlea adn resposne to differnet sond
Definition
differnet regions of the cochlea respond to different frequenceis of sound, This is due to the baisilar membrane beign stiffern ear hteo val awindow and mroe flexibile at the apex. As well as differeintiation in individual hair cells along the different potins of htebasilar membrane . at hte apex it is flopy adn better bass soudnign at the oval window is ist stiff and beter for higher frequency. THis is tonotopy. stereocilia chagnes mirror these basillar maembrane hcanges
Term
auditory afferent tonotopy
Definition
audotiroy afferents deisplay characteristic frequency- frequncy at hwich they are at hte lowest threshodl to fire
Term
cochlea innervation
Definition
8th cranial nerve. Most of the innervation coms for teh spiral ganglion, with the bipolar mostly innervating the inner hair cells, with many many bipoalr cels to one hair cell.

Outer hair cels get the remaining spiral gangliion innervation as wel als direct efferent fibers. Outer hair cells have to hsare their neurons cuz not enough
Term
intensity coding
Definition
caused by differnetial activation of the number of sensory afferents conecnted oth the innerh air cel. Loduer noise means more activation
Term
the cochelar nerve joiens up with eth veistblar nerve and both enter hte brainstem
Definition
Term
where do priamr ysensory afferets go to in teh brainstem
Definition
teh dorsal and ventral cochlear nucleus
Term
where do priamr ysensory afferets go to in teh brainstem
Definition
teh dorsal and ventral cochlear nucleus
Term
COchlea bilateraly represented
Definition
so uialteral deafness is not sene with elsions central to the cochelar nulcei
Term
dorsal choclear nucleus is located later to the vestibular nulceus in the dorsal medulla . ventral cochlear nerveh angs off the braisntem laterally (slide 22)
Definition
Term
choclear nucleus tonotopic
Definition
orderly sequence ararangemetn so tonotopci sequencei s preserved in cochlear nucleus
Term
cell typesi ncochlear nucleus
Definition
within the nulceus thereare celsl which fire at differnet rates, plays a role in teh localizaitno of sound.
Term
auditory pathway
Definition
characterized yb bilateral repreesentaiotn at each level
Term
what are the levels of the central auditory pathway
Definition
medulla dorsal nucleus of lateral lemniscus , ifnerior coliculus ,medial geniculate and cortex
Term
Medial superior olive function
Definition
we are able tot el ltiem difernece between soudsn etnering both ears. This is best iwth lwo frequency
Term
lateral superior olive function
Definition
we are able to tell itnensity diference between both ears, with high frequncy wqorking best
Term
sueprior medial olivary nucleus pathway
Definition
comes in primary affernets to superior olivary nucleus - Information is shared ,bilateral input coming from both ears
Term
localization of sound alogn the MSO based on time (slide 27)
Definition
the mSO have several differet uclei whihc are palced between the ears. THey are coincident detectors, only fire hwen soudn reaches at het same time. As ar esult E is the msot sensitive to pathways comign form the left ear , as thoug hteh sound comes earliest toh te lft ear it is comepnesated by going down the logner pathway. A for the right ear if ists leading. and C for comign in front of listeenter
Term
inferior coliculus frequency informaiton preserved
Definition
in isofrequency bands (cells within that band respodn to same frequenc)
Term
inferior ocliuclus-superior ocliculus
Definition
together create the startle reflex. Hve the visual adn auditory systems owrkign together
Term
inferior ocliculus proejcts to
Definition
medial genicualte, the thalamic relay station
Term
the auditory cortex
Definition
has tontoopci representatiosn and columanr organization- with that of suppressian dn excitation represented
Term
auuditory cortex pathologies
Definition
deafness if lesion is on both sides. Verbal agnosia- cant recognizze the osudns of speech ,thoug hthey can communciate fine by writing. nonverbal agnosia- cant recognize environemtnal noiceses. Unilateral lesion- not deafness but wont beablet o localize osudsn on contralateral sideo htel esion.
Term
core-betl
Definition
corei sht primary auditory area, teh blet is the secondary adutiory area
Term
lateralization of function in aduitory cortex
Definition
there are differnet areas for spepch, environment, music etc. and furthermore some are better representedi nright hemsiperhe vs lef t and vice versa
Term
Tinnitus types
Definition
tonal-subjective -soemthginw rong iwth auditory sensory and so on.

nontonal- stuff thaty ou can hear objective. has to do with vascualr system. blodo rushign etc.
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