Hair cells of auditory outer rows. These are stereocilia projecting from the auditory receptor cell surface into the endolyphatic duct. These pseudocilia meet the tectorial membrane that completes the mechanical linkage for mechanical displacement detecting sound-generated forces in the labyrinth fluid. Auditory receptor cells lack a kinocilium that is found in the vestibular system. This endolymph surface of these receptor cells is the site of transduction for sound energy. The small protuberance at the apex of the V is a vestigial kinocilium. A cuticle under the stereocilia tuft forms a plunger that compresses the hair cell cytosol. The soft spot around the vestigial kinocilium acts as a plasma membrane stretching zone and mechanical opening of channels is believed to activate hair cells.

• Hair cells of auditory outer rows. These are stereocilia projecting from the auditory receptor cell surface into the endolyphatic duct. These pseudocilia meet the tectorial membrane that completes the mechanical linkage for mechanical displacement detecting sound-generated forces in the labyrinth fluid. Auditory receptor cells lack a kinocilium that is found in the vestibular system. This endolymph surface of these receptor cells is the site of transduction for sound energy. The small protuberance at the apex of the V is a vestigial kinocilium. A cuticle under the stereocilia tuft forms a plunger that compresses the hair cell cytosol. The soft spot around the vestigial kinocilium acts as a plasma membrane stretching zone and mechanical opening of channels is believed to activate hair cells.

• Their base is contacted by afferent teledendra where transmitter in receptor cells is liberated onto peripheral nerve synapses. Hair cell depolarizations synaptically produce receptor potentials that lead to action potentials in the auditory nerve.