CD 225 Lecture Notes - Lecture 13: Inner Ear, Eustachian Tube, Audiology
29 Mar 2017
School
Department
Course
Professor
Document Summary
How widespread is hearing loss: 12 % in u. s have some degree of hearing loss, most common birth defect. 3 in 1,000 births: 83 in 1,000 children = educationally significant . Classifying hearing loss: impairment, disability, handicap. Big d deaf: deaf = hl > 90 db, deaf community/ deaf culture. Parts of the ear: outer ear: Lead to tympanic membrane: (eardrum) transmits sound waves, acoustic energy. The tympanic membrane: between the out & middle ear. Thing, strong, flexible: sound waves cause it to vibrate. Acoustic energy of sound way to mechanical energy. The middle ear: air filled, eustachian tube: Equalizes air pressure: ossicles (ear bones) Stapes ( stirrup : pushed by the eardrum, stapes pushes on opening to inner ear, ossicular chain acts like a lever o. Fluid-filled: sends signal: auditory nerve to brain. Hair cells trigger nerve signals: vestibular system.
