Communication Sciences and Disorders 4411A/B Lecture Notes - Lecture 4: Eustachian Tube, Ear Canal, Outer Ear
16 Oct 2018
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Document Summary
Hearing: sense through which spoken language or non-speech sounds are received, transmitted, and processed by auditory system, auditory system, peripheral auditory system outer ear to auditory nerve, central auditory system beyond auditory nerve to cerebral cortex. Peripheral auditory system: outer ear, middle ear, auditory nerve. Outer ear: key components, pinna, external ear canal. Functions: collects, funnels, and amplifies sounds, enhances sound pressure of high frequency sounds by ~5 db. Largely immobile; a vestigial muscle: shape of pinna helps direct the sound. Tunnel between pinna and eardrum: aka external auditory meatus, cartilaginous near pinna, fibrous near eardrum. Functions: protects eardrum from trauma, produces cerumen to keep skin moist and trap debris, enhances sound pressure of mid/high-frequency sounds by ~15 db. Middle ear: key components, middle ear cavity, tympanic membrane (eardrum, ossicles, eustachian tube. Located between external ear canal and cochlea: bone covered by thin mucous membrane, hollow space within temporal bone. Ideally, filled with air can become fluid filled.
