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Definition
| appendage on lateral surface of head; elastic cartilage; nearly vestigial structure in humans |
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| air-filled tubular space following slightly S-shaped course to TYMPANIC MEMBRANE; conducts sound to eardrum; contains ceruminous glands 0 secretion mixes with sebum to form CERUMEN - earwax |
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Definition
| convert sound waves into mechanical vibrations; air-filled space - TYMPANIC CAVITY, within temporal bone; 3 bones - AUDITORY OSSICLES; EUSTACHIAN TUBE; bounded by eustachian tube anteriorly and posteriorly by spongy bone of mastoid process, laterally bounded by tympanic membrane |
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| middle ear; irregular cone shaped; malleus attaches to it; core of radially and circularly arranged collagen fibers |
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Definition
MALLEUS (hammer) - attaches to eardrum, articulates with incus
INCUS (anvil) - largest ossicle, links malleus to stapes
STAPES (stirrup) - footplate fitting into oval window, small piston on cochlear fluid |
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Definition
| lies in bony canal above auditory tube; tendon inserts on malleus; contraction increase tension on eardrum |
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Definition
| posterior wall of middle ear; tendon inserts on stapes; contraction dampens movement of stapes at oval window |
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Definition
| mediated by tensor tympani muscle and stapedius muscle; ossicles become rigid, reducing transmission of vibrations to internal ear; reflex in response to intense sound |
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Definition
| connects middle ear to nasopharynx; ciliated pseudostrat columnar epi, 1/5 composed of goblet cells; equalizes pressure of middle ear with atmospheric pressure |
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Definition
| extend from middle ear into temporal bone; epithelial lining of air cells continuous with tympanic cavity and rests on periosteum |
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Definition
| complex system of interconnected cavities and canals in petrous part of temporal bone |
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Definition
| w/in bony labyrinth; complex system of small sacs and tubules forming continuous space enclosed w/in wall of epi and CT; COCHLEAR LABYRINTH, VESTIBULAR LABYRINTH |
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Term
| 3 fluid-filled spaces in internal ear |
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Definition
ENDOLYMPHATIC SPACE - membranous labyrinth; endolymp similar to intracellular fluid (high K+, low Na+)
PERILYMPHATIC SPACE - between bony labyrinth/membranous labyrinth; perilymph similar to extracellular fluid (low K+, high Na+)
CORTILYMPHATIC SPACE - w/in organ of Corti; true intercellular space; cortilymph with composition similar to extracellular fluid |
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| 3 spaces of bony labyrinth |
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Definition
semicircular canals
vestibule
cochlea |
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Definition
| small oval chamber in center of bony labyrinth; UTRICLE and SACCULE of membranous lab. lie in recesses |
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| extend from vestibule posteriorly; three tubes that lie at right angles to each other; extend from wall of vestibule and return to it - 3/4 circles; |
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| cone-shaped helix connected to vestibule; central core of spongy bone - MODIOLUS; sensory ganglion - SPIRAL GANGLION w/in modiolus; SECONDARY TYMPANIC MEMBRANE covers round window on inferior surface near base |
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Definition
| division of membranous labyrinth: 3 semicircular ducts w/in semicircular canals; utricle and saccule, connected by membranous utriculosaccular duct |
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Definition
| 3 located in membranous ampullae of semicircular ducts; sensitive to angular acceleration of head |
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| 2 - macula of utricle, macula of saccule - sense position of head and linear movement |
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Definition
| projects into endolymph of cochlear duct; sound receptor |
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Definition
| present in vestibular and cochlear labyrinths; function as mechanoelectric transducers; convert mechanical energy into electrical energy that's transmitted to brain; HAIR BUNDLE - rows of stereocilia, on surface of hair cell; each contains one cilium located behind row of longest stereocilia |
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Definition
| when deflected; pivot at proximal ends; MET channel protein activated when cross-linkage occurs - signal transduction K+ channels open; depolarization opens voltage-gated Ca2+ channels; secretion of neurotransmitter generates action potential in afferent nerve endings |
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Definition
| gelatinous protein-polysaccharide mass attached to hair cells of each crista ampullaris; projects into lumen, surrounded by endolymph; rotational head movement - endolymph lags due to inertia, sways projected cupula, deflects stereocilia between hair cells and cupula |
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Definition
| 3 parallel compartments: SCALA MEDIA (duct itself); SCALA VESTIBULI (space above); SCALA TYMPANI (space below) |
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Definition
| gelatinous polysaccharide material overlying maculae; outer surface contains crystalline bodies of calcium carbonate; stereocilia deflected by gravity when membrane and otoliths pull |
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Definition
| organ of Corti; supporting cells for both rows of hair cells |
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