PSYCH 1XX3 Lecture Notes - Lecture 7: Cochlear Nucleus, Basilar Membrane, Oval Window
Document Summary
Sound is the result of our interpretation of waves. Environmental impacts on adutory structure basilar membrane. Longer basilar membrane = wider range of frqeuncies. Changes in air pressure ear drum responds to air pressure changes. Compressed air molecules cause eardrum to be pushed inwards. Less dense air molecules cause eardrum to move outwords: amplitude (loudness) Every 10db increase, loudness doubles: frequency (pitch) Higher freqency = higher pitch sound: purity (timbre) The external ear: pinna, ear canal, narrows, amplifies sound waves, eardrum, vibrates at frequency of incoming sound wave. Contains neural tissue neccesary to translate changes in fliud to neural impulses. Higher freq cause end nearest to oval/round window to vibrate. Moves as fluid moves, converts to neural impulses. Synapses with bipolar cells that make up cochlear nerbve, a branch of main auditory nerve. Outer hair cells: more numerous, but slower (thin, unmyelinated), less connections with brain. Inner hair cells: less numerous, but faster (thick, mylenated), more connections with brain.
