Saturday, June 23, 2012

How Acoustic Vibrations are Transmitted to the Brain

You wonder how acoustic vibrations are transmitted to the brain? The acoustic vibrations, or sound, enter the ear through the auricle and ear canal. Then, the tympanic membrane (eardrum), located at the end of the ear canal, pick up these vibrations, passing them on to the auditory ossicles, which consist of three tiny bones called malleus (hammer), incus (anvil), and stapes (stirrup), that are joined together by ligaments. Then, the stapes, which is at the end of the auditory ossicles, transmits the vibrations into the cochlea through the fenestra ovalis (oval window).

Since the cochlea is filled with fluids, the vibrations coming from the ossicles transform into waves that travel through the three spiral tubes into which the cochlea is divided; the cochlea middle tube, called cochlear duct or scala media, contain the organ of Corti where the hair cells are located. As the waves travel throughout the upper and lower tubes of the cochlea, the hair cells in the middle tube are set in motion by this vibratory energy, thus turning the sound waves into nerve impulses that travel to the temporal lobe of the brain through the auditory nerve (cochlear nerve).

How sound is transmitted to the inner ear