auditory system 2

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What are the routes of sound conduction to the inner ear?: air and bone
What is the function of the middle ear?: amplify pressure oscillation during transmission from air to liquid
What is the acousitc stapedius reflex?: a loud sound causes a large discharge of the cochlear n which acitvites vent cochlear nucleus, sup olive, facial n. which causes tensing of stapedius muscle
Where is endolymph?: in membraneous labyrinth
Where is perilymph?: within the two scalae
What produces endolymph?: stria vascularis
What produces perilymph?: periosteal lining
What is the composition of endolymph?: low protein and Na, High K
What is the composition of the perilymph?: NaCl, low protein
How are varoius frequencies separated?: Low-helicotrema, high-near windows
What is the modiolus?: The bone surrounding the bony labyrinth
Where does the scala tympani run?: round window to helicotrema
Where does the scala vestibule run?: helicotrema to oval window. it is continuous with the bony vestibular labyrinth
What are the parts of the membranous labyrinth?: cochlear duct and organ of corti
What connects the membranous labyrinth together?: ductus reunions
What does the endolymph flow thru?: the endolymphatic sac and the endolymphatic duct
How many inner row?: 1
How many outer row?: 3
Hear cells receive inhibitory input from what?: the olivocochlear nerve fibers
What is the mem pot gradient between the endolymph and the hair cell?: 150mV
What opens the siral ligaments mecahnosensitive K channels?: movement of cilia towards the spiral ligament
What happens when K channels open?: depols, triggering Ca entry and NT release of Glut which activates cochlear nerve fibers
What is the trap door theory?: Movement of stereocilia away from the spiral ligament hyperpols the cell, but an intermediate position leads to a reduced level of K to maintain resting potential
What is the function of outer cells?: amplification of cilia movements
What forms the trapezoid body?: ventral cochlear nucleus projects to the ipsilateral and contralateral
Where does the dorsal cochlear nucleus project?: contralateral lemniscus terminating in lat lemniscus
What is the Rinne's Test?: mastoid process then lateral to ear, which is louder
What if bone conduction is louder is louder in Rinne Test?: conductive deafness
What if Webber test is louder in one ear?: conductive deafness in that ear
What is conduction deafness?: dec vibration of basilar membreane, dec air conduction, low frequencies
What causes conduction deafness?: foreign obejcts, infection
What is sensorineural deafness?: loss of both air and bone, high frequencies caused by haircell damage
What is neural deafness?: unilateral hearing loss because of leasion to auditory nerve
What is central deafness?: lesion to CNS

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Number of cards 34