HEALTHY CHOICES: Your Sense of Hearing

Ms. Mai

Lawndale High School

Your Sense of Hearing

Your ears are not only good for listening to your favorite songs, but also for walking, riding a bike, dancing, or any other activity that requires balance

We just learned that our eyes receive light rays and convert them to nerve impulses that our brains interpret as sight

Our ears are very similar

The Structure and Function

Ears receive sound waves and convert them into nerve impulses that our brain interprets as sound

Specialized structures in our ear help provide our sense of balance

Hearing

Your outer ear is shaped to collect sound waves moving through air

The sound waves travel through a short passageway called the external auditory canal

The external auditory canal is lined with hairs and earwax to help prevent dirt, bacteria, and other material from entering your ear

Outer Ear

The auditory canal ends at the eardrum, which is a thin membrane across the opening to the middle ear

The sound waves make the eardrum vibrate

Behind your eardrum are three tiny bones (hammer, anvil, and stirrup)

Middle Ear

The middle ear is filled with air that enters through the eustachian tube (connects the middle ear with the back of the throat and nose)

This connection keeps air pressure equal on both sides of the eardrum so it does not rupture when outside air pressure changes like on an airplane or in an elevator

Inner Ear

When the stirrup vibrate, the oval window also vibrates and passes on to a fluid in the cochlea (spiral tube containing receptors that sense vibration)

When the fluid vibrates, it moves the tiny hairs lining the cochlea and changes the vibrations into nerve impulses

Hearing

These nerve impulses travel along the auditory nerve from the ear to the brain

As with the eye and vision, you do not hear until the nerve impulses are interpreted by your brain

The brain can tell which direction sound wave are coming from each ear’s signals travels to a different part of the brain

Anatomy of the Ear

Balance

If you have ever gotten dizzy, you are experiencing movement in your semicircular canalsSemicircular canals are curved tubes that help provide your sense of balance, but play no role in hearing

The semicircular canals are filled with fluid and lined with tiny hairs so that when your head moves, the fluid moves which causes the hair to also move

Balance

The hairs are connected to nerve cells that send impulses to the brain, which then interprets and coordinates that information with impulses from your eyes and your muscles

All this information tells you the position of your body, how fast, and in which direction

Typically when people are dizzy, it is because the fluids in their semicircular canals are still moving

Common Ear Problems

Although the delicate parts of your ears are enclosed within your skull, they can still be damaged

Hearing loss from ear infections or other factors are very common

Ear Infections

Ear infections occur when bacteria or viruses travel from the nose or throat, up the eustachian tube, and into the middle ear

Ear infections cause fluid or pus to collect in the middle ear, which can distort or block your hearing

Ear infections can be cured with antibiotics

One way to prevent ear infections is to blow your nose gently

Hearing Loss

Hearing loss is caused by infections, obstructions, or nerve damageIn severe middle-ear infections, the eardrum can be damaged or even ruptured

If scars form while the eardrum if healing, they will prevent the eardrum from vibrating

Severe infections can also damage the three small bones in the middle ear, which can cause permanent hearing loss

Hearing Loss

An obstruction in the ear blocks sound waves

An obstruction may be due to buildup of wax or a bone blockage

Damage to nerve cells in the cochlea can cause hearing loss

This type of damage may develop over time and is usually caused by prolonged exposure to loud sounds

Caring for your Ears

Ear infections should be treated promptly because even a minor infection can lead to hearing loss

Although some types of hearing loss cannot be prevented, you can protect your ears against nerve damage

General Care for your Ears

Never try to clean inside your ear with Q-tips, hair pins, or other objects

Inserting objects into your ear can push wax further into the canal and pack it against the ear drum blocking your hearing, or puncture the eardrum and allow infection to enter the middle ear

You should only use washcloth to clean your outer ear

Preventing Hearing Loss

The best way to prevent hearing loss from nerve damage is to limit your exposure to loud sounds (loud is anything above 85 decibels)

The length of time you are exposed to loud sounds is as important as the loudness of the sounds

Listening to music at 95 decibels for two or three hours is as damaging as hearing a much louder sound for only a short time

Sound Levels

Strategies For A Healthy Ear

Try to avoid noisy places. If you cannot, then wear ear plugs when sounds become too loud. Ear plugs will not block out all sound, but they will reduce the loudness to a safe level

If you have to be in noisy places often, give your ears a rest from time to time by finding a quieter place

Keep the volume of stereos and radios turned down to a comfortable level. If you listen through earphones, keep the volume low enough so that you can still make out normal sounds around you. If the earphones are drowning out all other sounds, the volume is too high.