Function of the Ear
To understand how our hearing works we start a “virtual” tour through our ear.
When we speak about the ear we normally mean the auricle, the part of the ear we can see. But the ear is much more than that, and it is precisely the other part which makes the wonder of hearing possible.
-The outer ear collects the sound waves which are vibrations in the air and transports them through the auditory canal.
-These vibrations are carried through the auditory canal to the eardrum.
-The eardrum then passes the vibrations on to the middle ear.
-The middle ear with the smallest bones in the body (malleus, incus and stapes) converts the vibrations in the air into liquid movement which then reaches the inner ear
-In the inner ear, the cochlea, the liquid causes the basilar membrane to vibrate. This is where the actual spiral organ (of Corti) is located. Electric impulses are created in its approximately 20,000 hearing cells.
-The acoustic nerve receives the impulses and passes them to the brain stem.
-In the brain stem they are allocated to the appropriate “processing centre” in the brain. Here the signals from both ears are processed together.
-The brain’s “processing centres” link the incoming impulses of acoustic frequencies with the relevant information, and we understand what we have just heard. The brain’s “processing centres” link the incoming impulses of acoustic frequencies with the relevant information, and we understand what we have just heard.