Published Online: 15 JAN 2010
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Marcotti, W. and Masetto, S. 2010. Hair Cells. eLS. .
- Published Online: 15 JAN 2010
Hair cells are the sensory receptors in the inner ear that detect sound and head motion to begin the processes of hearing and balance control. The defining feature of hair cells is the hair bundle, the transduction organelle protruding from their apical surface composed of ordered arrays of stereocilia. Mechanical deflection of the hair bundle, normally induced by physiological stimuli, increases the open probability of mechanically gated cation channels located at the tip of stereocilia. The resulting depolarizing inward current generates a receptor potential. The information encoded in this electrical response is transmitted to the auditory or vestibular afferent nerve fibres via the Ca2+-induced release of neurotransmitter from the hair cell's basal pole. In this way sensory information is relayed to the brain enabling us to perceive sound and maintain balance. In mammals, hair cell loss causes irreversible balance and hearing impairment because these sensory cells show very little or no regenerative ability.
Hair cells are the sensory receptors of both the auditory and vestibular systems in vertebrates.
Inner ear hair cells derive their name from the stereocilia that protrude from their apical surface, which are deflected as a result of sound (cochlea) or head movement (vestibular organs) and initiate the sensory transduction process.
Cochlear hair cells convert acoustic stimuli into electrical activity that allows the brain to perceive the sensation of hearing.
Vestibular hair cells inform the central nervous system of head position and movements.
The hair bundle, the defining feature of all hair cells, is the mechano-receptive organelle directly responsible for mechano-transduction, i.e. for converting the natural stimulus into a neural signal.
In mammals, hair cell loss due to acoustic over-stimulation, ototoxic drugs, ageing and genetic defects is irreversible, leading to a permanent loss of function.
- auditory hair cells;
- vestibular hair cells;
- inner hair cells;
- outer hair cells;