The Ear

How do we hear? Your ears are sense organs that

respond to the stimulus of sound.

The sound waves are picked up from the surrounding air, and they are turned into nerve impulses that can be sent to the brain.

How do we hear? Sound waves carry a lot of

information (language, music, and noises) all mixed together.

The brain’s job is to sort the signals and make sense out of them.

What are sound waves?

Sound is produced by vibrations that travel as waves through the air.

The sound waves move outward from the sound and they travel through air, liquids and solids.

What are the parts of the ear?

There are three main sections of the ear: the outer ear, middle ear and inner ear.

Outer Ear Canal

Eardrum

Hammer

Anvil

Stirrup

Cochlea

Auditory Nerve

The sound waves enter the outer ear and make the structures in the middle ear vibrate.

When the vibrations reach the inner ear, nerve impulses travel to the brain.

The Outer Ear

The outer ear is the part of the ear that you can see.

Its shape helps to funnel the sound waves into the auditory canal.

The Middle Ear

The ear canal directs sound waves to the eardrum (tympanic membrane).

The eardrum vibrates and passes the vibrations on to the three bones in the middle ear.

The Middle Ear There are three bones in the

middle ear: › Hammer (also called Malleus)› Anvil (also called Incus)› Stirrup (also called Stapes)

These are the smallest bones in your body.

The Middle Ear

The vibrations pass from the eardrum to the hammer, to the anvil, to the stirrup.

Muscles in your ear adjust the tension on the eardrum, in response to the loudness of the sound.

The Inner Ear

The stirrup then vibrates against a thin membrane that covers the opening of the inner ear.

This membrane transfers the vibrations into the fluid in the cochlea.

The Inner Ear

The cochlea is a snail-shaped tube that is lined with receptor cells that respond to sound.

The Inner Ear

Sensory neurons then send these impulses to the brain, through the auditory nerve.

The Brain The brain sorts out the

different impulses and translates them into sound.