The cochlea is the sense organ that translates sound into nerve impulses to the brain. Each person has two cochlea, one for each ear. The cochlea is a fluid-filled, snail shaped cavern in the boney part of your skull near each ear. Tiny bones in the middle ear transmit sound from the ear drum across the middle ear and vibrate against the cochlea. Vibrations in the fluid cause tiny hair cells inside the cochlea to vibrate and generate nerve impulses that then travel to the brain.