Internal Ear

Internal Ear consists of two labyrinthine compartments, one contained within the other (bony labyrinth and membranous labyrinth), and three fluid filled spaces:

Bony labyrinth consists of three connected spaces within the temporal bone:

The structure of the membranous labyrinth consists of a series of communicating sacs and ducts containing endolymph. It is suspended within the bony labyrinth. The space between the membranous labyrinth and the bony labyrinth is filled with perilymph. There sensory cells are located in six regions:

Neural Transduction of sound production. Hair cells are attached through phalangeal cells to the basilar membrane, which vibrates during sound reception. Stereocilia of these hair cells are also attached to the tectorial membrane, which also vibrates. Stereocilia are therefore the only structures that connect the basilar membrane and its complex epithelial layer to the tectorial membrane. Tectorial and basilar membranes are hinged at different points, thus a shearing effect occurs between basilar and tectorial membranes when sound vibrations enter the inner ear. Shearing effect of both membranes distorts the stereocilia of hair cells. The apical membranes of hair cells ultimately depolarize.