PSY 368 Lecture Notes - Lecture 25: Otosclerosis, Nicotine, Aspirin
5 Dec 2017
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Document Summary
Eardrum thin layer of skin that vibrates in response to a pressure wave entering the auditory canal. Ossicles 3 tiny interconnected bones: malleus (hammer, incus (anvil, stapes (stirrup) Middle ear amplification: air-to-water impedance problem. Fluid-filled middle ear requires 1000x more energy to vibrate than air. Focus energy falling on eardrum onto smaller area amplifying signal. Use ossicles as lever to apply greater force on oval window (inner ear) Amplification offsets 80% of signal loss that would otherwise occur. 3 canals that spiral through length of structure: vestibular canal, tympanic canal, cochlear duct. Vestibular and tympanic canals filled with liquid (perilymph), but separated until very apex of cochlea (heliocotrema) where they come together. Stapes moves against oval window create pressure wave that travels down vestibular canal to heliocotrema back along tympanic canal to round window. Cochlear duct: isolated from vestibular canal by reissner"s membrane and from the tympanic canal by.
