ABSTRACT
In normal hearing, sound pressure variations entering the human inner ear are sensed in the organ of Corti by the hair cell’s stereociliary bundle on the apical membrane, then converted within the cell to transmitter release at the basal membrane. The latter generates an action potential in the fibres of the spiral ganglion neurones (Fig. 24.1). Two types of hair cells-–inner and outer-–work together to accomplish this highly efficient mechanism of sound processing: Outer hair cells frequency specifically amplify the mechanical signal, while inner hair cells convert the mechanical signal into neuronal impulses.
