Sound first enters our ear at the pinna, which is the visible part of the ear on the outside of our head. The pinna is designed to collect sound waves and funnel them down the ear canal towards the tympanic membrane (eardrum).
Together, the pinna and ear canal are referred to as the outer ear.
The middle ear starts with the tympanic membrane. As sound waves traveling down the ear canal reach the tympanic membrane, it vibrates like a drum.
Behind the eardrum is an air-filled space containing three tiny bones, the malleus, incus and stapes. They are the smallest bones found anywhere in the human body. The vibrations in turn cause these bones to vibrate. The middle ear consists of the eardrum, malleus, incus, stapes, and the air pocket in which they reside.
The cochlea and the semi-circular canals are organs of both hearing and balance. With the cochlear nerve (auditory nerve), they form the inner ear.
Sound passes to the inner ear via the vibrations of the middle ear bones, which are connected to the cochlea at one end.
Thousands of tiny sensory hair cells within the cochlea convert the vibrations into an electro-chemical signal that’s carried by the auditory nerve to the brain, where sound is processed and interpreted