Sensory hair cells in ear. Coloured scanning electron micrograph (SEM) of hair cells (brown/ pink) in a healthy inner ear. The inner ear converts sound waves into nerve impulses by stimulation of stereocilia (pink, upper frame), projections at the ends of the hair cells. Waves entering the inner ear displace the fluid that surrounds the stereocilia, causing the stereocilia to bend. This bending causes the hair cells to release neurotransmitter chemicals, which generate nerve impulses that travel to the brain along the auditory nerve. The inner ear can transmit information about the loudness and pitch of a sound. Magnification: x1750 at 6x7cm size.