Ear – the hearing organ
The three sections of the ear are the outer ear (the part we see), the middle ear, and the inner ear. The ear has a fourth functional part – the brain. More specifically, the auditory cortex of the brain.
How do we hear?
The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. A chain of little bones in the middle ear transmits vibrations to the inner ear. There they stimulate the fibers of the auditory nerve to send impulses to the brain. The external ear has only to concentrate air vibrations on the ear drum and make the drum vibrate. The middle ear communicates with the pharynx. It also manages equilibrium and transmits the ear drum vibrations to the inner ear.
The outer ear consists of the pinna or auricle, the meatus and the canal. . The auricle is the visible projecting part of the ear. The external acoustic meatus is the outside opening to the ear canal. The external ear canal leads to the ear drum.
The middle ear consists of the ear drum and a cavity. This cavity is connected to the pharynx via the Eustachian tube . The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure. As you’re descending in a plane, the Eustachian tube that opens when your ears “pop open”. The middle ear cavity contains a chain of 3 little bones that connect the ear drum to the internal ear. They are the malleus, incus, and stapes.
The internal ear is complex. We’ll deal with this part in a separate article.
Source: MedicineNet, Inc.