BIOL 102 Lecture Notes - Lecture 20: Oval Window, Basilar Membrane, Semicircular Canals
Document Summary
Auditory canal transmission: carries sound waves from pinna to middle ear, middle ear and inner ear are imbedded in bone in cranium, absent or reduced in marine mammals, middle: imbedded in bone. Tympanic membrane (tympanum) vibrate amplification. Ear bones: amplification and transmission, evolved from lower jaw bones (advantages: stronger bite and sound amplification: malleus attached to tympanic membrane, incus, stapes attached to oval window. Eustachian tube (connects middle ear to throat) equalize pressure with outside environment and middle ear chamber: inner : imbedded in bone; responsible for changing signal for interpretation. Round window absorbs displacement of fluid inside cochlea (stabilizes) Utricle + saccule + semicircular canals (3 not in all vertebrates) balance and detection of movement. Response to different frequencies: stimulation of certain stereocilia; due to flexibility of the membrane. Proximal end (beginning) of basilar membrane (near oval and round windows) is thin and stiff only vibrates to high frequency.
