The sense of hearing is integral to our interaction with our
environment, yet the cellular components of the inner ear
are vulnerable to a variety of damaging agents. All hearing
sensation is derived from the output of a remarkably small
number of sensory cells: fewer than 15 000 per inner ear.
These hair cells are the mechanoelectrical transducers of
the ear; deflections of the stereotypical bundles (the hairlike
structures that give hair cells their name) on their
apical surfaces lead to transmitter release from their
basolateral poles, leading, in turn, to action potentials in
the auditory nerve fibers.