Outer hair cells (magnified)
Cellulae sensoriae externae
Sensory (eye & ear)OrgansWhole body
- What it is
- Three rows of cylindrical cells, about 12,000 per ear, each topped by a V- or W-shaped bundle of stereocilia in three rows of graded height, the tallest embedded in the tectorial membrane.
- Function
- The cochlear amplifier: the motor protein prestin makes them shorten and lengthen with each sound cycle, boosting basilar-membrane vibration up to a thousand-fold and sharpening frequency tuning.
- Size
- Real length 25-70 micrometres (longer toward the apex), diameter about 8 micrometres.
- Clinical note
- Their motion produces otoacoustic emissions, used to screen newborns for hearing. They are the first cells destroyed by loud noise and by ototoxic drugs such as gentamicin and cisplatin.