How the Ear Works
Before one can truly understand hearing damage or loss, it is necessary to understand how the ear actually works.
The ear consists of three main parts:
- Outer Ear – consisting of the pinna, ear canal and eardrum
- Middle Ear – consisting of the ossicles (malleus, incus, stapes) and ear drum
- Inner Ear – consisting of the cochlea, the auditory nerve and the brain
The Outer Ear
To expand more on what the outer ear is, it is the portion of the ear that you can actually see. This part opens to into the ear canal collecting sound waves where the sound is amplified. Sound waves then travel toward the oval membrane which is located at the end of the external auditory meatus called the tympanic membrane (eardrum). The ear drum is what separates the ear canal from the middle ear. As sound waves are collected, the tympanic membrane then begins to vibrate.
The Middle Ear
The vibrations from the eardrum allow the ossicles to further amplify the sound. The ossicles are three tiny bones (smallest in the human body): Malleus (hammer), Incus (anvil) and Stapes (stirrup). As you can see from the image, the three small bones are directly behind the tympanic membrane and are connected to the middle ear. The ossicles takes mechanical vibrations received at the tympanic membrane into the inner ear.
The Eustachian tube (opening into the middle ear) acts as an air pressure equalizing system. The middle ear is encased in bone and does not associate with outside air except through the Eustachian tube.
The Inner Ear
The sound waves enter the inner ear and then into a snail shaped organ called the cochlea. This part of the ear fills with a fluid that moves in reply to the vibrations from the oval window. Nerve endings then respond and are set into motion transforming the vibrations into electrical impulses. They are then passed to the auditory nerve located in the brain. Your brain then translates these signals and creates what we actually hear. It is also important to note that the inner ear contains the vestibular organ that is responsible for balance.
Enjoy this video that clearly articulates how the ear works as well: