The Inner Ear

The small bone called the stirrup, one of the ossicles, exerts force on a thin membrane called the oval window, transmitting sound pressure information into the inner ear.

The inner ear can be thought of as two organs: the semicircular canals which serve as the body's balance organ and the cochlea which serves as the body's microphone, converting sound pressure impulses from the outer ear into electrical impulses which are passed on to the brain via the auditory nerve.

The basilar membrane of the inner ear plays a critical role in the perception of pitch according to the place theory.

The Semicircular Canals

The semicircular canals, part of the inner ear, are the body's balance organs, detecting acceleration in the three perpendicular planes. These accelerometers make use of hair cells similar to those on the organ of Corti, but these hair cells detect movements of the fluid in the canals caused by angular acceleration about an axis perpendicular to the plane of the canal. Tiny floating particles aid the process of stimulating the hair cells as they move with the fluid. The canals are connected to the auditory nerve.