BMS 870 Lecture Notes - Lecture 15: Stapes, Epsp Synthase, Semicircular Canals
24 Dec 2017
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Document Summary
Cycle - distance bw successive compressed patches of air. Sound frequency - # cycles per sec in hz. Intensity (amplitude) - high intensity sound is louder than low intensity. Pinna collects sound and directs it to auditory canal which ends at typmpanic membrane (eardrum). Ossicles are series of bones connected to eardrum which transfer movements of eardrum into movements of second membrane covering oval window (hole). Fluid-filled cochlea transforms physical motion of oval window to neuronal response. Output to thalamus, the medial geniculate nucleus (mgn), to primary auditory cortex. Tympanic membrane -> 3 ossicles -> footplate moves in and out at oval window which transmits sound vibration to inner ear. To move cochlear fluid, more pressure is needed to vibrate the fluid than the air can provide. The ossicles provide this necessary amplifi cation in pressure. Greater p at oval window than at tympanic membrane = movement of fluids.
