[1] In mammals, the auditory hair cells are located within the spiral organ of Corti on the thin basilar membrane in the cochlea of the inner ear.

They derive their name from the tufts of stereocilia called hair bundles that protrude from the apical surface of the cell into the fluid-filled cochlear duct.

The stereocilia number from fifty to a hundred in each cell while being tightly packed together[2] and decrease in size the further away they are located from the kinocilium.

Instead, the influx of positive ions from the endolymph in the scala media depolarizes the cell, resulting in a receptor potential.

It is thought that this tonic release is what allows the hair cells to respond so quickly in response to mechanical stimuli.

The electrical resonance for this method appears as a damped oscillation of membrane potential responding to an applied current pulse.

Prestin's function has been shown to be dependent on chloride channel signaling and that it is compromised by the common marine pesticide tributyltin.

Because this class of pollutant bioconcentrates up the food chain, the effect is pronounced in top marine predators such as orcas and toothed whales.

[18] Calcium ion influx plays an important role for the hair cells to adapt to the amplification of the signal.

[19][20] More recent research now shows that the calcium-sensitive binding of calmodulin to myosin-1c could actually modulate the interaction of the adaptation motor with other components of the transduction apparatus as well.

[19] The resultant decreased tension in the tip link permits the bundle to move farther in the opposite direction.

[23] The neurotransmitter released by hair cells that stimulates the terminal neurites of peripheral axons of the afferent (towards the brain) neurons is thought to be glutamate.

The presynaptic terminal bouton is filled with vesicles containing acetylcholine and a neuropeptide called calcitonin gene-related peptide.

Because hair cells of auditory and vestibular systems in birds and fish have been found to regenerate, their ability has been studied at length.

[6][25] In addition, lateral line hair cells, which have a mechanotransduction function and are found in anamniotes, have been shown to regrow in species such as the zebrafish.

[26] Researchers have identified a mammalian gene that normally acts as a molecular switch to block the regrowth of cochlear hair cells in adults.