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 canals Semicircular 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 damage In 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.