Structure of the cochlea, computer artwork. Cross section of the organ of Corti, the auditory sense organ, which lines the spiral of the cochlea in the inner ear. It contains four rows of hair cells (orange), three to the left (outer hair cells) and one to the right (inner hair cells). On top of these cells are stereocilia, which touch the tectorial membrane (purple, top) and detect tiny movements in the membrane. These movements are as a result of sound-induced pressures in the inner ear fluids. The hair cells translate these movements into electrical impulses, which travel down the nerve fibres (blue) to the brain, where they are deciphered as sound.