BCS 151 Lecture Notes - Lecture 17: Basilar Membrane, Oval Window, Ear Canal
11 Nov 2016
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Document Summary
As one drops down, another one starts to give the. Lecture 18: hearing illusion of an endless descent. Functions: sound pick-up & amplification, impedance matching & sound gating, frequency analysis. Sound: increase in amplitude = increase in loudness, increase in frequency ear drum vibrates faster, a loud sound is produce when the speaker generates a large vibration. The large vibrations produce large waves of compressed air: the middle ear acts like a level system that transfers energy to the cochlea. The ossicles transmit vibrations from the large ear drum to a smaller drum called the oval window: functions of the middle ear. Impedance matching: forceful vibrations displace the oval window against the cochlear fluid. Gating: only helps you with sustained exposure to loud noises. Dampens the muscles: round window: acts to relieve the pressure. Wider & floppier at the apex (low frequencies) Narrow & rigid at the base (high frequencies: white noise vibrates throughout the basilar membrane, travelling wave theory.
