INT PHYS EXAM1 studyguide4

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INT PHYS EXAM1 studyguide4
2011-10-02 19:51:26
INT PHYS EXAM1 studyguide4 EAR

INT PHYS EXAM1 studyguide4 EAR
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  1. the anatomy of the outer ear
    • pinna
    • ear canal
    • typanic membrane
  2. the anatomy of the middle ear
    • malleus
    • incus
    • stapes
  3. the anatomy of the inner ear
    • oval window
    • cochlea
    • cochlear duct
    • tympanic duct
    • round window
  4. Define how sound is transduced
    • sound waves vibrate tympanic membrane which causes the bones of the inner ear to vibrate
    • vibration of stapes is translated to the oval window which causes vibrations in the fluid of the inner ear
    • the movement of fluid in cochlear duct moves the tectorial membrane which then moves cilia on hair cells
  5. how is sound transformed into electrical signals
    in the hair cells
    • as a hair cell is bent in one direction it causes the cell to depolarize and release more glutamate to initiate greater AP frequency in the associated sensory neuron
    • the louder the sound, the greater the depolarization, and the greater the frequency of AP's generated in the afferent neurons
  6. Describe how frequency is coded on the basilar
    • Membrane stiffer/narrower near the oval window(start)
    • membrane wide/flexible near helicotrema(end)
    • HIGH freq - causes greatest deflection of oval window
    • LOW freq - causes greatest deflection of helicotrema
  7. Define what the semicircular canals, utricle and
    sacule are involved in
    • semicircular canals detect rotational (angular) acceleration
    • ---ant. canal : head up or down (yes)
    • ---post. canal : head up or down to the side (ear to ear)
    • ---lat. canal : head side to side (no)
    • utricle detects forward and backward acceleration via stereocilia
    • saccule detects acceleration up or down via stereocilia
  8. Describe how hair cells generate electrical signals in the vestibular apparatus
    within the ampulla, stereocilia are embedded in gelatinous endolymph. drag of endolymph during movement bends hair cells in opposite direction of movement