CSD-2260 Lecture Notes - Lecture 5: Cerebral Cortex, Endolymph, Outer Ear
1 Dec 2016
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Document Summary
Auditory mechanism: process the acoustic signals of speech, has an amazing range of sound pressures, has a frequency range of around 10 octaves spanning 20-30 hz. An octave is a doubling in frequency. Organizing physiological principles of auditory system: outer ear. Funnels acoustical information to the external auditory meatus. Funnels sound to tympanic membrane: middle ear. Matches airborne acoustic signal with fluid medium of cochlea. Contains these structures: tympanic membrane, the ossicles, entry to the cochlea, oval window. Increases the pressure arriving at the cochlea: cochlea is a fluid-filled cavity. Impedance is resistance to the flow of energy. Primary function: match the impedance of two conductive systems. Outer ear and cochlea: three impedance matching mechanisms. Buckling effect provides a 4-6 db gain. These matching devices combined cause a signal gain of around 31 db: disorders that impede middle ear function reduce audition. Performs temporal and spectral analysis on ongoing acoustic signal.
