BIO 208 Lecture Notes - Lecture 8: Superior Olivary Complex, Basilar Membrane, Cochlear Nucleus
31 Mar 2018
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Document Summary
The human ear - sound waves lead to vibration of basilar membrane. Vibration needs to be converted into fluid vibration; requires a transducer. Air vibrations alo(cid:374)g (cid:272)a(cid:374)"t (cid:272)ause hai(cid:396) (cid:272)ells to (cid:271)e(cid:374)d. This is initiated by vibration of the tympanic membrane (vibrates differently according to different air waves; moves up/down -- transversely)causing the malleus and incus (levers) to push the stapes (piston) in and out of the oval window. This produces a pressure difference in the (cochlear) fluid across the basilar membrane causing it to vibrate. Vibration of the basilar membrane in the cochlea causes a shearing force that leads to deflection of hair cells which depolarizes them, releasing transmitter that initiates action potentials in the 8th nerve fibers of the auditory nerve. The impulses are sent to the brain; our interpretation of it is sound. Result: mechanical energy (sound waves) is transduced (converted) to electrical energy (action potentials). Distribution of frequencies on the basilar membrane.
