Organ of Corti, SEM

Coloured scanning electron micrograph (SEM) of a section through the organ of Corti in the cochlear of the inner ear. The tectorial (upper) membrane (upper right corner) has been lifted. V-shaped arrangements of outer hairs (stereocilia, white) lie on top of a single outer hair cell (red). The hairs are surrounded by endolymph fluid. As sound enters the ear, it causes waves to form in the endolymph, which in turn causes these hairs to move. Outer hair cells amplify the vibrations, which are then picked up by inner hair cells (rows of hairs at right) that transmit the signal to auditory nerve fibres. This amplification enhances the sensitivity and dynamic range of hearing. At far left are Hensen's cells, a type of support cell. Magnification: x900 when printed at 15cm wide.