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23 Cards in this Set
- Front
- Back
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What is the roof of the cochlear canal? What is the floor? What is on the lateral cochlear wall?
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Roof is vestibular membrane separating scala vestibuli from duct. Floor is basilar membrane separating scala timpani from duct. On lateral wall is the spiral ligament, which is the lateral attachment of the basilar membrane and the stria vasicularis which produces endolymph
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What is the purpose of outer hair cells in the cochlea?
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contractile hairs that change the stiffness of the basilar membrane in response to electrical current
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What is conductive hearing loss?
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When sound is not transmitted thru middle/outer ear
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What is sensorineural hearing loss? What can cause it?
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damage to inner ear or nerve pathways to brain. Caused by diseases, drugs, head trauma, aging, tumors, and noise
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What are some drugs that can cause hearing loss? What part of ear is affected?
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amingoglycoside antibios, anti-cancer cis-platinums, salicylates, quinin, loop diuretics
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What are some causes of tinnitus?
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noice induced or medicine, as well as underlying health problems (blood vessels, heart, allergies, tumors)
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Where must a lesion be in order to cause unilateral hearing loss?
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More peripheral then the cochear nucleus
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What is the route of auditory neurons from cochlea to brain?
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primary neurons-- cochlear nuclei on inferior peduncle-- (dorsal nuclei axons cross trapezoid to LL) ventral nuclei axons to to Sup. Olivary nucei on both sides of pons-- Lateral Lemniscus-- Inferior Colliculus-- Medial Geniculate Nuclei-- Superior Temporal Gyri
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What do neurons leaving the dorsal cochlear nucleus in the Lateral Lemniscus carry information about?
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Information about the frequency spectrum of sound stimuli
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Do axons decussate before, after, or while they are in the lateral lemniscus? When axons are decussating, where do they cross and what to they cross ontop of?
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before they are in the LL. They cross in the pons overtop of the medial lemniscus
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What is the superior olivary nuclei neurons important for?
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localization of sound source as they the Sup Ol Nuc are receiving axons from both sides of brainstem
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What is the inferior colliculus involved in?
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auditory reflexes and sound localizations
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Where is the primary auditory cortical region?
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on the dorsal surface of the temporal lobe deep within the lateral fissure
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Where is Wernicke's area located and what is it important in? If it is lesioned, what happens?
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located on the posterior superior temporal lobe. It is involved w/ language comprehension (putting words to objects). If lesioned people make "word salads"
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Where is Broca's area, what's it involved in and what happens if it is lesioned?
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Located on parietal lobe along lateral fissure just superior to tip of temporal lobe. Involved in produxn of sound and verbal expression. Lesion causes them to not articulate
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How is sound transduced from outer ear into the inner ear?
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tympanic membrane picks up vibrations and through a lever system of ossicles in middle ear, concentrates movements onto oval window.
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What do you call it when muscles of middle ear (stapedius and tensor tympani) protect ear from loud noises?
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gating
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what is the funxn of the round window?
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allows the oval window to be displaced causing pressure in cochlea to be increased. accomplishes this by bulging
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How are auditory nerve cells activated by sound?
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in cochlea, oval window sends vibration of certain frequency down scala vestibuli causing basilar membrane to bend hair cells. This opens up K channels causing the hair cell to depolarize
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What is the base of the basilar membrane by the oval window like? What type of frequencies does it best pick up?
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It is narrow and stiff so picks up high frequencies best
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When a particular ear is turned away from the sound, which frequencies are best picked up?
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low frequencies because the head doesn't cast a shadow
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How do the ears detect sound direction?
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Sound intensity differences were the ear facing the sound hears high frequencies and ear away gets low, timing differences used to localize low frequency sounds, shape of ear lobe, other sensory modalities
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What do cells in lateral superior olive detect? medial superior olive?
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Lateral sup olive detects differences in sound intensity. Medial sup olive detects timing differences
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