The Eustachian tube connects the middle ear with the Naso-pharynx. It opens on swallowing to allow air to enter the middle ear to equalize pressure on both sides of the ear drum. The inner ear contains the organs for equilibrium and hearing. The semicircular canals, a non-auditory part of the inner ear, helps to keep the body's equilibrium. The auditory nerve is connected to the Organ of Corti.
Signals travel through the auditory nerve to the brain for processing.
The vibration of air moves the lever of Ossicles, which amplifies and transmits vibrations across the middle ear. This causes the footplate of the Stapes to move backwards and forwards in the Oval Window. The vibrations move the cilia in the inner ear. Each cilium is connected to a specific receptor site for particular ranges of vibration. This receptor site translates vibrations to electrical signals, which stimulates the brain.