The ear consists of three main parts:
- Outer Ear
- Middle Ear
- Inner Ear
The visible portion of the outer ear is called the pinna. It acts like a bowl to collect sound waves and channels them into the ear canal where the sound is amplified. These sound waves then travel toward a flexible membrane at the end of the ear canal called the tympanic membrane or the eardrum. The eardrum begins to vibrate whenever it comes into contact with sound waves.
The vibrations from the eardrum then set the ossicles into motion. The ossicles are three tiny bones, the smallest in the human body, and are named the malleus (hammer), incus (anvil), and stapes (stirrup). These bones work in conjunction 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.
Once the sound waves enter the inner ear, they travel into a snail shaped organ called the cochlea. The cochlea is filled with a fluid that moves in response to the vibrations from the oval window. As the fluid moves, thousands of nerve endings are then set into motion. These nerve endings transform the vibrations into electrical impulses that travel along the auditory nerve to the brain.
The brain then interprets these signals as sound and this is how we hear. The inner ear also contains the vestibular organ that is responsible for balance.