organ of Corti

3.43  organ of Corti. A series of neuroepithelial hair cells (receptor cells for hearing) and their supporting structures lying against the osseous spiral lamina and the basilar membrane within the scala media of the cochlea. The organ of Corti extends from the base of the cochlea to its apex.

Annotation            In cross-section, the inner and outer pillar cells (rods of Corti) of the organ of Corti form the triangular inner tunnel of Corti. The inner rods rest on the edge of the osseous spiral lamina and the outer rods rest on the basilar membrane. A single row of sensory cells (inner hair cells) is found on the inward side of (medial to) the inner rods (toward the modiolus), and three or four rows of sensory cells (outer hair cells) are located on the outer side of the outer rods. The upper ends of the hair cells form part of the reticular lamina that is supported by the rods of Corti and constitute the upper surface of the organ of Corti. The tectorial membrane, in which the hairlike processes extending from the upper ends of the outer hair cells are imbedded, lies above the reticular lamina. Nerve fibers of the cochlear nerve make contact with the lower ends of the inner and outer hair cells.