2. Hearing is one of the five human senses.
Hearing | Sight | Smell | Taste | Touch

4. How We Hear We use our ears to hear sounds.
Sounds travel through the air and our ears as sound waves.

5. How We Hear
Sound waves are collected by the outer part of the ear, called the pinna.
The pinna is the only part of the ear that you can see with your eye.

6. How We Hear
After the sound waves are collected by the pinna they are sent through the ear canal before reaching the ear drum.
When the sound waves hit the ear drum, it vibrates.

7. How We Hear
The vibrations from the ear drum makes three small bones in the ear vibrate.
The hammer
The anvil
The stirrup
Those three bones together are called the ossicles.
stirrup
anvil
hammer

8. How We Hear
The vibration of the ossicles transfer the sound waves to the inner ear.
The inner ear has two parts, the cochlea and the semicircular canals.
The semicircular canals. help you determine movement and to stay balanced.
semicircular canals
cochlea

9. How We Hear
As the sound waves pass through the cochlea, they cause microscopic hair cells to vibrate.
These hair cells, called cilia, are linked to the auditory nerve. When the cilia vibrate they send an electric impulse signal to the brain.
When the signal reaches the brain, we hear!
auditory nerve
cochlea
Cilia
From David J. Lim. Functional Structure of the Organ of Corti: A Review. Hearing Research, 22 (1986)

10. Taking Care of Our Ears
Just like our eyes and teeth, we need to make sure we take care of our ears.
The people who take care of our ears are called AUDIOLOGISTS.

11. Audiologists
An audiologist is the person you visit to have your ears checked.
He or she will look inside your ears with a tool called an otoscope.
The otoscope lets the audiologist see if you have anything stuck in your ears that shouldn’t be.

12. Audiologists
Audiologists also test your hearing using beeps, words, and other sounds.
During a hearing test, an audiologist will have you sit in a special room, that is completely quiet, to see what sounds you can hear.
Sometimes the audiologist will have you point out pictures that go with the sounds, or play games where you have to listen to the sounds.

14. Some Reasons We Lose Our Hearing
Babies are sometimes born not hearing as well, or not hearing at all.
Adults and kids can lose their hearing from being around noises that are too loud (noise-induced hearing loss – NIHL).
As adults get older, they can start to lose their hearing.
Some diseases can make you lose your hearing.

15. Types of Hearing Loss Sensorineural Hearing Loss
Conductive Hearing Loss
Mixed Hearing Loss
The safest way to determine if you have a hearing loss is to visit your audiologist for a hearing evaluation. An audiologist can then work with you to determine the best treatment option for your hearing loss.

17. Sensorineural Hearing Loss
When the cilia in the cochlea become broken or bent, they no longer vibrate correctly and the electric impulse signal does not get sent to our brain.
Once those hair cells break or bend, they can never be fixed.
Noise-induced hearing loss or NIHL, happens when we are around noises that are too loud, causing our cilia to over vibrate and become damaged.
From David J. Lim. Functional Structure of the Organ of Corti: A Review. Hearing Research, 22 (1986)

18. Conductive Hearing Loss
Conductive hearing loss happens when the sound
waves are not able to reach the inner ear.
Some of the reasons this can happen are:
Blockage in the ear canal from:
Ear wax (cerumen) build-up.
A foreign object lodged in there.
Fluid occupying the middle ear space.
This happens a lot due to ear infections, also called otitis media.

19. Mixed Hearing Loss
Hearing loss that involves both sensorineural and conductive hearing loss.

20. Hearing Aids If you have a hearing loss, sometimes an audiologist will
recommend that you get a hearing aid.
Hearing Aids are:
Special devices you place in your ear to help you hear better.
Comfortable to wear and come in a lot of colors and designs.

21. Remember to spell out E A R S to protect your hearing.
E - Earplugs (wear them when it’s too noisy)
A - Avoid loud sounds
R - Reduce the sound (turn down the volume)
S – Shorten the time you listen to the noise (less than 30 minutes)

23. If you think you or someone you know might have a hearing problem
If you think you or someone you know might have a hearing problem? Tell your parents to go online to to find an audiologist near you. Questions???