PCL 9 - Anatomy of the EAR

The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts all work together so you can hear and process sounds.

The Outer Ear: Catch the Wave

• Pinna


• External Auditory meatus


• Tympanic membrane

-The outer ear is called the pinna or auricle.

- This is the part of the ear that people can see. It's what people pierce to wear earrings

- The main job of the outer ear is to collect sounds
-The outer ear also includes the ear canal, where wax is produced.
Earwax protects the canal. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean.

The Middle Ear: Good Vibrations

• air-conditioning space connected to the nasopharynx


• 3 ossicles = malleus, incus, stapes

The middle ear's main job is to take those sound waves and turn them into vibrations that are delivered to the inner ear.
-The eardrum, which is a thin piece of skin stretched tight like a drum.
-The eardrum separates the outer ear from the middle ear and the ossicles
-Ossicles are the three tiniest bone in our body . They include:
the malleus, which is attached to the eardrum and means "hammer" in Latin
the incus , which is attached to the malleus and means "anvil" in Latin
the stapes , the smallest bone in the body, which is attached to the incus and means "stirrup" in Latin

When sound waves reach the eardrum, they cause the eardrum to vibrate. When the eardrum vibrates, it moves the tiny ossicles — from the hammer to the anvil and then to the stirrup. These bones help sound move along on its journey into the inner ear.

The Inner Ear: Nerve Signals

• Semicircular canals


• cochlear


• Eustachian tube

-Sound comes into the inner ear as vibrations and enters the cochlea a small, curled tube in the inner ear. The cochlea is filled with liquid, which is set into motion, like a wave, when the ossicles vibrate.
-The cochlea is also lined with tiny cells covered in tiny hairs .
- When sound reaches the cochlea, the vibrations (sound) cause the hairs on the cells to move, creating nerve signals that the brain understands as sound.