PSL300H1 Lecture Notes - Lecture 14: Cholinergic, Dyslexia, Brainstem

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9 Nov 2011
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Must have output for compressed fluid pressure . Endolymph-filled chamber sitting on top of basal membrane dividing cochlea into upper and lower where pressure pulses exterted. Close to windows, stiff membrane so high natural freq to oscillate at; ~20,000hz; goes to window instead of fluid, max vibration at window. Broad at other end, very flexible, much lower natural freq, as high; 30-50hz; goes thru all fluid for max vibration at apex of basal membrane so membrane tuned to dif freqs. Psl300h1f l14; oct. 14, 2011: mechanoreceptor system, hair receptors problem is mechanical - stimulus = seq of pressure pulses in air collected in auditory canal. Problem = must amplify pressure exterted on cochlea to maintain in fluid which is denser than air. Tympanum vibrates with sequence of sound pressure pulses (in air) lever system of ossicles amplifies pressure on tympanum 22-fold amplified pressure exerted on oval window of cochlea (filled with fluid)