ANP 1106 Lecture Notes - Lecture 18: Vestibular Duct, Cochlear Duct, Ear Canal

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1106
• Professor: Joanne Savory

Document Summary

Sound is a pressure disturbance (alternating areas of high and low pressure) originating from a vibrating object. It is composed of areas of rarefaction and compression, and is represented by a sine wave in wavelength, frequency, and amplitude. Amplitude: intensity of a sound measured in decibels (db) Frequency: the number of waves that pass a given point in a given time. Pitch: perception of different frequencies (we hear from 20-20,000 hz cycle/s) Number of waves that pass a given point in a giv- en time. Height of the sine wave crest that reveals a sound"s intensity. Sound vibrations beat against the eardrum (tympanic membrane). The eardrum pushes against the ossicles (little bones), which presses fluid in the inner ear against the local and round win- dows. This movement sets up shearing forces that pull on hair cells, with moving hair cells stim- ulating the cochlear nerve that sends impulses to the brain.