The Cochlea

The cochlea converts vibrations of the stapes into neural activity in auditory-nerve fibers.

“Cochlea” means snail in latin

From Dr. David Furness, Keele University

Inside the Cochlea

Inside the Cochlear Partition is the Organ of Corti

From the CIBA Collection of Medical Illustrations, Volume 1

 The motion of the stapes causes the cochlear partition to move up and down.

 This motion makes the stereocilia on the top of both the inner and outer hair cells move side-to-side.

 This motion creates electric voltage changes in the hair cells.

 Auditory-nerve fibers attached to the hair cells produce action potentials in response to these voltages.

Some Interesting Facts

 Although there are roughly three times as many outer hair cells as inner hair cells, 95% of the auditory-nerve fibers innervate the inner hair cells.

 Because the cochlea is encased in very hard bone, few scientific measurements have been made of movements or voltages in the coochlea.