One of the specific sensory cells of the organ of hearing (organ of Corti) One end has hairlike projections (cilia) that are imbedded in or in contact with the tectorial membrane The other end is in close contact with many nerve endings There are about 400 hair cells per millimeter and about 80 cilia per cell (2 ) One of the specific sensory cells of the organ of balance within the vestibule and semicircular canals of the inner ear