Cochlea a protein motor called prestin on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This "active amplifier" is essential in the ear's ability to amplify weak sounds. The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal through the middle ear (otoacoustic emissions). Otoacoustic emissions are due to a wave exiting the cochlea via the oval window, and propagating back through the middle ear to the eardrum, and out the ear canal, where it can be picked up by a microphone. Otoacoustic emissions
Cochlea interpreted. Two of the three fluid sections are canals and the third is a sensitive 'organ of Corti' which detects pressure impulses which travel along the auditory nerve to the brain. The two canals are called the vestibular canal and the tympanic canal. The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue. This coiled tube is divided through most of its length by an inner membranous partition. Two fluid-filled outer spaces ("ducts" or "scalae") are formed by this dividing membrane. At the top of the snailshell-like coiling tubes, there is a