The Outer Ear – The visible part of the ears is called the Pinna and it channels sound waves into the ear canal in order to amplify the sound. The sound waves then travel down the canal towards a flexible, oval membrane at the end called the eardrum. This membrane begins to vibrate once the sound waves hit it.
The Middle Ear – These vibrations of the eardrum then set the ossicles, or bones within the middle ear, into motion. These are the three tiny bones (smallest in the human body) in the middle ear: Malleus (hammer), Incus (anvil) and Stapes (stirrup) and their job is to further amplify the sound. The stapes attaches to the oval window that connects the middle ear to the inner ear. The Eustachian tube, which opens into the middle ear, is responsible for equalizing the pressure between the air outside the ear to that within the middle ear.
The Inner Ear – The sound waves travel next into the inner ear and into a spiral shaped organ called the cochlea. This organ is filled with a fluid that moves in response to the vibrations, and as a result, thousands of nerve endings are then set into motion. These nerve endings transform the vibrations into electrical impulses that then travel along the auditory nerve to the brain. The brain then interprets these signals and this is how we hear. The inner ear also contains the vestibular organ that is responsible for balance.