How the Ear Works and Common Issues
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How It Works and
Things That Can Go Wrong
The ear serves two functions: hearing and
balance.
The organs for these functions are the
cochlea for hearing and the semicircular
canals for balance.
The pinna funnels sound into the ear canal.
Sound waves go through the ear canal and
vibrate the eardrum (typanic membrane).
The vibrations are transmitted through and
amplified by the ossicles (middle ear bones).
Movement of the ossicles pushes at and pulls
away from the fluid in the inner ear.
The movement of the fluid in the inner ear
moves the hairs in the sensory cells of the
cochlea.
These cells send impulses from the cochlea
through the auditory nerve to the auditory
cortex of the brain.
*The ear is changing sound energy to
vibrations, to nerve impulses. Anything that
stops the flow of energy can cause hearing
loss.
Auditory Cortex – the area of the brain that
receives and translates information about
sound.
Auditory Nerve – a nerve that stretches from
the cochlea to the brain. It carries messages
from the ear to the brain.
Cochlea – a part of the inner ear. It is shaped
like a snail. There are many tiny nerve
endings inside the cochlea.
Decibel – a unit for measuring how loud or
soft a sound is.
Ear Canal – the passage that carries sound
from the pinna to the eardrum.
Eardrum (Tympanic Membrane) – a small
opening inside the ear that is covered with
skin. The eardrum moves back and forth
when sound hits it. The eardrum lies
between the outer and middle ear.
Eustachian Tube – tube connecting middle ear
to the throat (drains fluid from the ear).
Frequency – the number of sound waves per
second that a sound makes. This tells how
high or low a sound is.
Hertz – a unit for measuring the frequency of
a sound
Ossicles – malleus, incus, and stapes, the
three tiny bones in the middle ear. These
are the smallest bones in the body.
Outer ear – first section of the ear. It
includes the pinna and the ear canal.
Middle ear – second section (we can’t see it).
It contains the ossicles.
Inner ear – third section (can’t see). It
contains the semicircular canals, cochlea,
and auditory nerve.
Pinna – the part of the ear that we see
outside the head. It catches sound.
Semicircular Canals – the structures (fluid-
filled) that control the sense of balance.
Sound Waves – how sound travels. Sound
moves in waves that we cannot see.
1.
Conductive Hearing Loss – anything that
goes wrong in the outer or middle ear.
These can include:
- wax buildup in the ear canal
- infections in the ear canal that cause
swelling
- infection, scarring, or holes in the
eardrum
- fluid buildup in middle ear
- limited movement of the ossicles
2.
Sensorineural Hearing Loss – any problems
which occur in the inner ear. These can
include:
- drug-induced damage of the cochlea
(chemotherapy, etc.)
- trauma to the cochlea (blow to the head,
noise damage, etc.)
- age-related hearing loss (presbycusis)
- a tumor on the auditory nerve
- some infections, such as meningitis
3.
Mixed Hearing Loss – both conductive and
sensorineural hearing loss.
4.
Central Hearing Loss – when there is a
problem in the auditory cortex of the brain.
This is the least common.
Many times, Conductive Hearing Loss can be
corrected by medication or surgery.
Most of the time, Sensorineural or Central
Hearing Loss can’t be corrected.
Mild – difficulty hearing soft speech
Moderate – difficulty understanding conversa-
tions, especially if there is background noise.
TV and radio volume must increase.
Severe – normal speech is inaudible. May
only be able to hear loud or amplified
speech.
Profound – completely deaf
More than 28 million Americans have some
degree of hearing loss. About 2 million of
them are considered profoundly deaf.
Limit your time in loud places.
Wear earplugs in noisy situations.
Don’t sit too close to speakers at concerts.
Turn your headphones down! If the person
sitting next to you can hear the music, it’s
too loud.
Decibel Levels:
50-60 decibels
normal conversation
80-85
city traffic, garbage
disposal
90-95
lawn mower
100-120
chainsaw, tractor
130 +
headphones
110-140
rock concert, jet take-
off, shotgun,
jackhammer
At 85 decibels, you should use hearing
protection for extended exposure.
At 100 or more decibels, you should not go
more than 15 minutes without hearing
protection.
At 140 decibels, repeated exposure of more
than one minute can cause hearing loss.
The ear functions for hearing and balance, with the cochlea for hearing and semicircular canals for balance. Sound waves are funneled through the pinna, vibrate the eardrum, pass through the ossicles, and move fluid in the inner ear to transmit nerve impulses. Important terms include auditory cortex, auditory nerve, cochlea, decibel, and more.
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Presentation Transcript
THE EAR How It Works and Things That Can Go Wrong
FUNCTION OF THE EAR The ear serves two functions: hearing and balance. The organs for these functions are the cochlea for hearing and the semicircular canals for balance.
HOW DOES THE EAR WORK? The pinna funnels sound into the ear canal. Sound waves go through the ear canal and vibrate the eardrum (typanic membrane). The vibrations are transmitted through and amplified by the ossicles (middle ear bones). Movement of the ossicles pushes at and pulls away from the fluid in the inner ear.
HOW DOES THE EAR WORK? (2) The movement of the fluid in the inner ear moves the hairs in the sensory cells of the cochlea. These cells send impulses from the cochlea through the auditory nerve to the auditory cortex of the brain. *The ear is changing sound energy to vibrations, to nerve impulses. Anything that stops the flow of energy can cause hearing loss.
VOCABULARY Auditory Cortex the area of the brain that receives and translates information about sound. Auditory Nerve a nerve that stretches from the cochlea to the brain. It carries messages from the ear to the brain. Cochlea a part of the inner ear. It is shaped like a snail. There are many tiny nerve endings inside the cochlea.
VOCABULARY (2) Decibel a unit for measuring how loud or soft a sound is. Ear Canal the passage that carries sound from the pinna to the eardrum. Eardrum (Tympanic Membrane) a small opening inside the ear that is covered with skin. The eardrum moves back and forth when sound hits it. The eardrum lies between the outer and middle ear.
VOCABULARY (3) Eustachian Tube tube connecting middle ear to the throat (drains fluid from the ear). Frequency the number of sound waves per second that a sound makes. This tells how high or low a sound is. Hertz a unit for measuring the frequency of a sound
VOCABULARY (4) Ossicles malleus, incus, and stapes, the three tiny bones in the middle ear. These are the smallest bones in the body. Outer ear first section of the ear. It includes the pinna and the ear canal. Middle ear second section (we can t see it). It contains the ossicles. Inner ear third section (can t see). It contains the semicircular canals, cochlea, and auditory nerve.
VOCABULARY (5) Pinna the part of the ear that we see outside the head. It catches sound. Semicircular Canals the structures (fluid- filled) that control the sense of balance. Sound Waves how sound travels. Sound moves in waves that we cannot see.
TYPES OF HEARING LOSS Conductive Hearing Loss anything that goes wrong in the outer or middle ear. These can include: - wax buildup in the ear canal - infections in the ear canal that cause swelling - infection, scarring, or holes in the eardrum - fluid buildup in middle ear - limited movement of the ossicles 1.
TYPES OF HEARING LOSS (2) Sensorineural Hearing Loss any problems which occur in the inner ear. These can include: - drug-induced damage of the cochlea (chemotherapy, etc.) - trauma to the cochlea (blow to the head, noise damage, etc.) - age-related hearing loss (presbycusis) 2.
TYPES OF HEARING LOSS (3) - a tumor on the auditory nerve - some infections, such as meningitis Mixed Hearing Loss both conductive and sensorineural hearing loss. 3. Central Hearing Loss when there is a problem in the auditory cortex of the brain. This is the least common. 4.
TYPES OF HEARING LOSS (4) Many times, Conductive Hearing Loss can be corrected by medication or surgery. Most of the time, Sensorineural or Central Hearing Loss can t be corrected.
DEGREES OF HEARING LOSS Mild difficulty hearing soft speech Moderate difficulty understanding conversa- tions, especially if there is background noise. TV and radio volume must increase. Severe normal speech is inaudible. May only be able to hear loud or amplified speech. Profound completely deaf
More than 28 million Americans have some degree of hearing loss. About 2 million of them are considered profoundly deaf.
PREVENTING NOISE-INDUCED HEARING LOSS Limit your time in loud places. Wear earplugs in noisy situations. Don t sit too close to speakers at concerts. Turn your headphones down! If the person sitting next to you can hear the music, it s too loud.
PREVENTING NOISE-INDUCED HEARING LOSS Decibel Levels: 50-60 decibels 80-85 normal conversation city traffic, garbage disposal lawn mower chainsaw, tractor headphones rock concert, jet take- off, shotgun, jackhammer 90-95 100-120 130 + 110-140
PREVENTING NOISE-INDUCED HEARING LOSS At 85 decibels, you should use hearing protection for extended exposure. At 100 or more decibels, you should not go more than 15 minutes without hearing protection. At 140 decibels, repeated exposure of more than one minute can cause hearing loss.
