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42 Cards in this Set
- Front
- Back
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What are the parts of the external ear?
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1) concha
2) pinna 3) auditory meatus 4) tympanic membrane |
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What are the parts of the middle ear?
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1)ossicles
2) stapedius 3) tensor tympani |
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What is conductive hearing loss?
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something that interferes with the external ear or middle ear's ability to transfer sound to inner ear
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What is sensineural hearing loss?
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inner ear is effected so either cranial nerve 8 or the hair cells themselves
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What is the cochlear partition made of?
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tectorial and basilar membrane
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What is the organ of corti?
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ribbon of sensory epithelium which runs down cochlea scala media and contains hair cells
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What do acoustic signals do in the cochlea?
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they initiate a wave of the same frequency which moves from base to apex of basilar membrane growing in amplitude until the point of maximum displacement and then hair cells respond to that specific freqeuncy
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What are inner hari cells?
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main sensory receptors of cochlea that sens vibration of organ of Corti to cochlear nuclei in brain stem
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What are outer hair cells?
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target of efferent innervation and possess a unique type of mobility that allows them to be amplifiers
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What are the characteristics of the base of the cochlea? (3)
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1)stiff
2) narrow 3) high frequency |
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What are the characteristics of the apex of the cochlea?
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1)floppy
2) wide 2) low frequncy |
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What happens to the frequency as you get away from teh stapes?
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freqenucy decreases
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What happens when you stretch the stereocilia apart from each other?
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open cation sensitive channels at end of link and depolarize the hair cell
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What happens when you compress the tip links?
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close channels and cause hyperpolarization
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Where are the compartments of the perilymph and endolymph located with relation to the basilar and tectorial membranes?
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perilymph is outside of the scala media in scala tympani or scala vestibuli it is either over the tectorial membrane or under the basalar membrane
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What is the relative composition of endolymph to perilymph to hair cell ?
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endolymph- low K, 0 mV
perilymph - hi K, 80 mV hair cell: -45mV |
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How do you drive K into hair cell?
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perilymph is higher in K than hair cell
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What happens once you depolarize the hair cells?
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1)open more voltage gated Ca and K channels in hair cell soma
2) K goes from apical end to basilar end 3) Ca coming from voltage gated channel causes NT release to afferent nerve cell |
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What is the central pathway for processing auditory information?
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1) hair cell 2) spiral ganglion 3) auditory nerve 4) ventral cochlear nucleus 5) superior olive 6) lateral lemniscus 7) inferior colliculus 8) MGN 9) auditory cortex |
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What is the ratio of hair cell to auditory nerve fiber?
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1:1 which gives the tuning curve because each hair cell is tuned to a specific frequency so each auditory nerve is tuned to a spcific frequency
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What is the difference between auditory nerves in apical end vs basilar ends?
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apical end - low frequency
basilar end - high frequency |
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What is the MSO nucleus for?
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detecting coincidence when excitatory signals arrive at same time. useful for localizing sound under 3Hz
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What is used to for localizing sounds above 3Hz?
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LSO and MNTB
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What analysis interaural intensity?
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LSO
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What does the midbrain do ?
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merge auditory information
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What does the lateral lemniscus do?
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signal onset of sound and duration for monaural
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What does the inferior colliculus do?
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auditory space map
process sound with complex temporal pattern |
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What does the auditory thalamus do
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belt areas and medial areas
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What is the primaru auditory cortex?
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superior temporal gyrus which has precise temporal map from MGN
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What is the secondary auditory cortex?
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belt areas also known as A1, behind lateral sulcus near Wernicke's area
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What is the difference between hearing aids and cochlear implant?
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hearing aids amplify sound
cochlear implant - compensate for damaged or non working parts of ear |
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Can cochlear implants restore normal hearing?
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no
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What is the primary auditory cortex essential for?
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frequency discrimination and sound lcoalization
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Where is the primary auditory cortex located?
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superior temporal gyrus
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What are the structures that hearing implants bypass?
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1) ear canal
2) tympanic membrane 3) oval window 4) hair cells |
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What do cochlear implants do then?
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they stimulate auditory nerve directly
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What is the mechanism of how cochlear implants work?
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1)perform fourier analysis on sound
2) excite cells to degree that their frequency is active 3) have alot of electrodes 4) number of electrodes they have determines function |
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How is cochlear implant surgery performed?
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general anesthesia
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When can the pt be able to hear after the surgery?
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1 month
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What are factors that influence performance of cochlear implants on patients?
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1)age of onset of hearing loss
2)age of implementation 3) duration of cochelar implant |
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What are two ways to test newborn hearing
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1)ABR (auditory brainstem response testing)
2)OAE (otoacoustic emissions testing) |
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What is the most common birth defect?
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hearing loss
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