PHGY 209 Lecture Notes - Lecture 20: Basilar Membrane, Oval Window, Cochlear Duct

• School: McGill University
• Department: Physiology
• Course: PHGY 209
• Professor: Alvin Shrier

Document Summary

Mediated by mechanoreceptors taking the physical energy (sound/waves/gravity) and mechanically opening/closing ion channels. Air molecules around our ears become close together, increasing pressure and vice versa. The change in pressure is what we hear. Frequency = number of cycles per second = pitch. Amplitude = difference between highest and lowest pressure. Advancing age and presbycusis progressive bilateral hearing loss with increasing age. High frequency perception is lost as we get older. Folds in the ear are reflecting frequencies into the external auditory canal. Inner ear: contains cochlea, where transduction process occurs. Semicircular canals: give sense of acceleration of the head. Oval (flexible) and round windows: how mechanical information of sound gets into the cochlea. Saccule: vertical acceleration (going up and down) Flow of sound energy: eardrum is pushing and pulling the small bones, which push and pull the oval window, behind the oval window is fluid amplification process, modulated by skeletal muscles.