PSYCH 2E03 Lecture Notes - Stapedius Muscle, Middle Ear, Psych

• School: McMaster University
• Department: Psychology
• Course: PSYCH 2E03
• Professor: Gautam Ullal

Document Summary

Function of ossicles inner ear is filled with fluid that is much denser than air. Outer and middle ear are filled with air. Pressure changes in air transmit poorly into the denser medium. Ossicles act to amplify the vibration for better transmission to the fluid. Middle ear muscles dampen the ossicles" vibrations to protect the inner ear from potentially damaging stimuli. Muscles of the ossicles & the attenuation reflex. Hyperacousis increased sensitivity and intolerance to sounds within the normal range of amplitudes (occasionally to one"s own voice) commonly caused by paralysis of stapedius muscle (tiniest skeletal muscle) innervated by vii cranial nerve (facial nerve) Internal ear cochlea, and the vestibular apparatus cochlea for hearing. Vestibular apparatus for the sense of posture structure important for hearing is the cochlea fluid-filled snail-like structure (35mm long) set into vibration by the stapes. Divided into the scala vestibule and scala tympani by the cochlear partition.