Cochlea the oval window) to the "apex" (the top or center of the spiral). The spiral canal of the cochlea is a section of the bony labyrinth of the inner ear that is approximately 30 mm long and makes 2¾ turns about the modiolus. The cochlear structures include: The cochlea is a portion of the inner ear that looks like a snail shell (cochlea is Greek for snail.) The cochlea receives sound in the form of vibrations, which cause the stereocilia to move. The stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be
Evolution of the cochlea cells and their afferent innervating fibers can be very sharply tuned to frequency. In birds and crocodilians, the similarity of the structure of the basilar papilla betrays their close evolutionary relationship. The basilar papilla is up to about 10mm long and contains up to 16500 hair cells. While most birds have an upper hearing limit of only about 6 kHz, the barn owl can hear up to 12 kHz and thus close to the human upper limit. Egg-laying mammals, the monotremes (spiny anteater and platypus), do not have a spiral cochlea, but one shaped more like a banana, up to