Sound transduction by Organ of Coi is initiated by:

Organ of Coi consists of hair cells, the receptors for transduction. Hair cells are surrounded by endolymph. Endolymph has a rich concentration of K+. Basilar fiber vibration, caused by pressure in sound wave, leads to shearing between tectorial membrane and reticular lamina. It causes bending of stereocilia (at the top of hair cells), resulting in opening of the K+ channels at the base of the hair cells. The hair cells are depolarized by influx of K+. It leads to release of the transmitter by the hair cell at its base where it synapses with the VIII nerve fiber. Impulses are then sent in the VIII nerve.