Inner ear. Artwork of the sensory organs of the human inner ear. The inner ear contains a maze of fluidfilled passages called the labyrinth (pink). The cochlea (lower right) is a hollow spiral that contains microscopic hairs that respond to sound vibrations from the middle ear (not seen). Nerves (brown) connected to the cochlea carry the sound information as electric impulses to the brain. The three loops at top are the semicircular canals. These provide the sense of balance by detecting movement of fluid through the three planes.