Term
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Definition
-vestibucochlear apparatus -structures are concerned with perception of sound and balance |
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Term
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Definition
1. External Ear -collects sound waves 2. Middle Ear -transmits sound waves to inner ear 3. Inner Ear -converts sound waves to nerve impulses -impulses sent to brain via acoustic nerve -contains vestibular organ = balance
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Term
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Definition
Pinna -> External Auditory Meatus -> Temporal Bone
Pinna = convoluted elastic cartilage covered by skin External Auditory Meatus = lined by hair-bearing skin with submucosal sebaceous and cerumen glands External auditory meatus enters temporal bone
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Term
| External Auditory Meatus - Ceruminous Glands |
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Definition
-simple coiled tubular glands -secrete waxy stuff for protection |
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Term
| External Auditory Meatus - Structure |
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Definition
-outer third = supporting wall of elastic cartilage remainder is temporal bone
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Term
| Seperation of External from Middle Ear |
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Definition
-tympanic membrane seperates -fiberous and elastic connective tissue -lined on outer surface by skin -lined on inner surface by simple cuboidal epithilium (same as middle ear) |
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Term
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Definition
-bordered by: tympanic membrane, temporal bone, and inner ear -communicates with: mastoid air cells posteriorly nasopharynx anteriorly via auditory (eustachian) tube
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Term
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Definition
-medial wall = 2 membrane covered structures = no underlying bone 1. oval window 2. round widow -tympanic membrane conncect with oval window via a. malleus b. incus c. stapes |
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Term
Middle Ear Malleus Incus Stapes |
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Definition
-transmit vibration stimuli to oval window and then to inner ear -have innervating synovial joints (simp. squam. epith) -malleus and stapes -each have muscle attachment that helps regulate passage fo sound
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Term
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Definition
-composed of 2 labyrinths -bony -membraneous |
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Term
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Definition
-casing within temporal bone -houses the mebraneous labyrinth -central widening contains vestibule -inside lies dilated utricle and saccule -branching off of utricle = 3 semicircular canals -anterior vestibule leads to cochlea |
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Term
Membraneous Labyrinth (4 Parts) |
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Definition
-lined by simple squamous epithelium -attached to periosteum of bony labyrinth -Divided into: 1. Saccule and Utricle 2. Semicircular Canals 3. Endolymphatic Duct and Sac 4. Cochlear Duct |
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Term
Membraneous Labyrinth - Saccule and Utricle |
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Definition
-composed of neuroepothelial cells -cells communicate with vestibulocochlear nerve -each cell is called macula |
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Term
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Definition
In saccule - on the floor
In utricle - on lateral wall -In saccule and utricle = perpindicular to each other -has 2 kinds of receptor (hair) cells -has supporting cells -has afferent and efferent nerve endings |
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Term
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Definition
-posses up to 80 stereocillia in rows -increase in length as they approach cilium
-one cilium (kinocilium) on apical surface -covered by gelatenous layer -contains otoliths on outer surface |
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Term
| Macula - Hairs cells transmit Action Potential |
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Definition
-mass of structures displaced during head movement -sterocillia bends = action potentioal to brian via
vestibucochlear nerve |
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Term
| Membraneous Labyrinth - Semicircular Canals |
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Definition
-receptors found in dilated areas -adjacent to the utricle called ampullae -arranged in long ridges -called cristae ampullares (contact opposite wall of ampullae) |
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Term
| Semicircular Canals - Structure |
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Definition
Similar to Macule but: -gelatinous layer is thicker and conical in shape -referred to as capula -NO OTOLITHS
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Term
| Semicircular Canals - Function |
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Definition
-determine body position via fluid (endolymph) movement in canals Movement in canals = tilts the capula = bending of receptor cell stereocilia = stimulate/inhibit signals depends on direction of tilt |
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Term
Membraneous Labyrinth - Endolymphatic Duct and Sac |
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Definition
-absorb endolymph -scavenge any debris that may be present within the endolymph |
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Term
Membraneous Labyrinth - Cochlear Duct (3 spaces) |
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Definition
-responsible for reception of sound -in cross-section has 3 spaces 1. Scala Vestibuli (superior): contains perilymph 2. Scala Media (cochlear duct): contains endolymph -terminates at end of cochlea 3. Scala Tympani (inferior): contains perilymph Scala Vestibuli and Tympani = 1 tube that runs from oval to round window |
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Term
| Cochlear Duct - Structure |
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Definition
Vestibular (Reissner's) Membrane -seperates scala vestibuli and media -double-layer simple squamous epithelium Scala Media -lateral wall = stria vascularis (sim. cub. epi.) -highly folded basal aspect -transports fluid into lumen -modifies fluid in lumen to form endolymph |
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Term
| Cochlear Duct - Hearing Component |
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Definition
Organ of Corti (contains hearing receptors) |
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Term
| Cochlear Duct - Organ of Corti |
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Definition
Consists of: -hairs cells that respond to diff sound frequencies -supporting cells Outer Hair Cell: -present in 3-5 rows -contain curved pattern of stereocilia Inner Hair Cell: -linear pattern of stereocilia NO CILIUM End of longest outer stereocilia contact tectorial membrane |
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Term
| Organ of Corti - Hair Cells |
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Definition
-both outer + inner posses afferent + efferent innervation -parakaryons of afferent neurons make spiral ganglion -located in adjacent bone
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Term
| Cochlear Duct - Pillar Cells |
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Definition
-type of supporting cell -line the inner tunnel -considered important for sound transmission |
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Term
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Definition
1. Sound waves hit tympanic membrane 2. Ossicles vibrate 3. Vibration transmited to oval window 4. Vibrations move to perilymph of scala vestibulu 5. Vibrations move through vestibular membrane 6. Vibrations move to endolymph of scala media 7. Sound waves move to perilymph of scala tympani 8. Tympani causes Organ of Corti to vibrate 9. Vibrations displace basilar membrane (underlies hair cells)
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Term
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Definition
10. Hair cells vibrate relative to the tectorial mem 11. Stereocilia is deformed 12. Generates action potential 13. AP transmitted through cochlear branch of vestibulocochlear nerve to the brain |
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