Middle ear

There are three sections of the ear.

They are the external ear, the middle ear, and the inner ear.

The middle ear consists of the ear drum (the tympanum or tympanic membrane) and, beyond it, a cavity.

This cavity is connected via a canal (the Eustachian tube) to the pharynx (the nasopharynx).

The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure (so, as you're descending in a plane, it's the Eustachian tube that opens when your ears 'open').

The middle ear cavity also contains a chain of 3 little bones (ossicles) that connect the ear drum to the internal ear.

The ossicles are named (not the Nina, the Pinta and the Santa Maria, but) the malleus, incus, and stapes.

In terms of function, the middle ear communicates with the pharynx, equilibrates with external pressure and transmits the ear drum vibrations to the inner ear.