The ears are responsible for hearing and balance. They are divided into three different sections, the Outer, Middle and the Inner ear. The outer ear is responsible for directing sound in your ear canal and gives a sense of direction to you..

Middle ear: Is an air filled narrow space connected with the back of ones throat by a small tube called the Eustachian tube. There are three tiny bones which stretch from the eardrum to the inner ear and are responsible for transmitting sound from the former to the latter.

Inner ear: has two parts, the cochlea, for hearing and the vestibule for balance. Cochlea is a spiral snail like tube and has thousands of hair cells along the length of the cochlea. These hair cells are connected to the auditory nerve (the nerve of hearing) which takes signals from the cochlea to the brain.
When sound is picked from the outer ear and passed to the middle ear and then to the cochlea, the hair cells trigger an electronic impulse that is transmitted to the brain by the hearing nerve. The brain understands as sound like an alarm clock ringing or somebody calling your name.