Bellwork: The Ear

• What is the function of the ear?• Are there different parts?  If so, can you

name them?• How does the ear work? • What is that sound?

A Story About the Ear Mrs. Mackens

Anatomy of the Earo Outer Ear

• Pinna• Ear Canal• Outer layer of the eardrum

o Middle Ear• Hammer• Anvil• Stirrup

o Inner Ear• Cochlea• Nerves• Semicircular Canals

How Sound Travels First, sound is collected by the pinna (the visible part of

the outer ear) Then, it is directed into the outer ear canal Next, sound makes the eardrum vibrate Now, the vibration causes three tiny bones in the inner

ear to vibrate Hammer Anvil Stirrup

Vibration of the eardrum

How Sound Travels

Finally, the vibration is transferred to the snail-shaped cochlea in the inner ear

The cochlea is lined with sensitive hair cells (cilia)

The hair cells (cilia) trigger the generation of nerve signals that are sent to the brain

Outer Ear

Pinna- the visible part of the outer ear. It collects sound and directs it into the outer ear canal.

Ear Canal- the tube through which sound travels to the eardrum

Outer layer of eardrum- (tympanic membrane) vibrates when sound waves reach it

Middle Ear

Hammer (Malleus)- a tiny bone that passes vibrations

Anvil (Incus)- a tiny bone that passes vibrations from the hammer to the stirrup

Stirrup (Stapes)- a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body. (.25 to .33 cm long)

Eustachian tube- a tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside.

FUN FACT

• Babies can get earaches because of milk backing up in the Eustachian tube, which causes bacteria to grow and may cause hearing problems later in life.

• An earache is caused by too much fluid putting pressure on your eardrum. Earaches are often the result of an infection, allergies or a virus.

FUN FACT

Inner Ear Cochlea- a spiral-shaped, fluid-filled inner ear structure;

it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form.

Nerves- these carry electro-chemical signals from the inner ear (the cochlea) to the brain.

Semicircular Canals- Fluid filled tubes attached to the cochlea that help us maintain our sense of balance.

Stirrup

Anvil

HammerPinna

Semicircular Canals

Nerves

Eustachian Tube

Eardrum

Outer Ear Canal

Cochlea

Day or Night, Ears Keep You Upright

• When you move your head, the liquid in the semicircular canals moves, too.

• The liquid moves the tiny hairs, which send a nerve message to your brain about the position of your head.

• In less than a second, your brain sends messages to the right muscles so that you keep your balance.

Dizzy yet?• Sometimes the liquid in your semicircular

canals keeps moving after you've stopped moving. – spin in circles or go on the Tilt-A-Whirl at the

amusement park.• Your brain is getting two different

messages and is confused about the position of your head.

Balance Disorders• A condition that makes you feel unsteady

or dizzy, as if you are moving, spinning, or floating, even though you are standing still or lying down.

• Can be caused by viral or bacterial infections in the ear, a head injury, or blood circulation problem. Many people experience problems with their sense of balance as they get older.

Hearing Loss

• There are three kinds of hearing loss:–Sensorineural–Conductive–Mixed hearing loss

Sensorineural Hearing Loss

• Also known as nerve deafness• the inner ear or actual hearing nerve itself

is damaged• About 90% of all people with hearing

impairments suffer from sensorineural hearing loss

• Most common

Sensorineural Hearing Loss

• Usually permanent• not medically or surgically treatable• In most cases, the cillia or the nerves from

the inner ear to the brain are irreparably damaged.

• wearing hearing aids may be of significant benefit

Conductive Hearing Loss

• outer and/or middle part of the ear fail to work properly

• Sounds become "blocked" and are not carried all the way to the inner ear (where hearing is still normal)

• Not permanent; temporary hearing loss

Mixed Hearing Loss

• A combination of a conductive and sensorineural hearing loss

• Both the middle and inner ear are involved

Causes of Sensorineural Hearing Loss

• the natural aging process • exposure to loud noises • infection or other disease • a genetic disorder• Tinnitus, or ringing in the ears, is usually

associated with sensorineural hearing loss

Causes of Conductive Hearing Loss

• a buildup of fluid in the middle ear • wax in the ear canal • puncturing of the eardrum • problems or injury to the bones or

membrane — which carry sound from the external ear through the middle ear to the inner ear.

Causes of a Mixed Hearing Loss• This hearing disorder can also occur when a

person first just has a permanent sensorineural hearing loss and then also develops a conductive hearing loss.

• For example, a person who already has a sensorineural loss gets a middle ear infection, and the two types of loss combine to create a greater hearing loss.

• Some other instances of mixed hearing loss are the result of the outer and inner ear being malformed, which causes both types of hearing loss

Treatment

• Conductive hearing loss can be easier to remedy than sensorineural or mixed hearing loss.

• It is usually treatable with either medical or surgical intervention

• In cases where medical/surgical intervention is not an option, a hearing aid can be very helpful.

Treatment

• Sensorineural hearing loss is usually permanent

• no medically or surgically treatable. In most cases, the nerves from the inner ear to the brain are irreparably damaged.

• However, most people with this hearing loss find wearing hearing aids to be of significant benefit

Treatment for Mixed Hearing Loss

• With mixed hearing loss, the conductive part may be treated, but the sensorineural part is usually permanent.

Hearing Instruments

• Small, comfortable, and almost invisible• Consists of a microphone, an amplifier or

processor and a speaker, which transmits the enhanced sound waves into your ear.

• A tiny battery supplies the necessary power

Hearing Instruments

• The ear remains open and receptive to those sounds which can still be heard naturally.

• They amplify speech, tones and sounds exactly when they need to.

• In complex hearing situations they pick out the signals you really want to hear.

Hearing Instruments

• That they focus the hearing on the desired source, and block out unwanted background noise. You can now hear the person you are speaking with, despite loud music and background conversation.

• In cases of moderate hearing loss, modern hearing aids can restore up to 100% of hearing capability.

Types of Hearing Instruments

• In-the-ear models (ITE or ITC/CIC models)

• Behind-the-ear models (CRT and BTE models)

Levels of Hearing Loss

• Bilateral- both ears are impaired• Unilateral- one ear is impaired

Bilateral Hearing Loss

• Mild• Moderate• Severe• Profound

Mild Hearing Loss• A mild hearing loss may cause you to miss 25-

40% of the speech signal. • Usually this results in problems with clarity since

the brain is receiving some sounds but not all of the information.

• Symptoms of mild hearing loss include problems understanding someone farther away than a normal distance for conversation, or even up close if the background environment is noisy.

• Weak voices are also difficult to understand for people with mild hearing losses.

Moderate Hearing Loss

• A moderate hearing loss may cause you to miss 50-75% of the speech signal.

• This means you would not have problems hearing at short distances and understanding people face-to-face, but you would have problems if distance or visual cues changed.

• Symptoms of moderate hearing loss include problems hearing normal conversations and problems hearing consonants in words

Severe Hearing Loss• People with severe hearing loss have difficulty

hearing in all situations. • Speech may be heard only if the speaker is

talking loudly or at close range. • A severe hearing loss may sometimes cause you

to miss up to 100% of the speech signal. • Symptoms of severe hearing loss include

inability to have conversations except under the most ideal circumstances (i.e., face-to-face, in quiet, and accompanied with speechreading).

Profound Hearing Loss

• Profound hearing loss is the most extreme hearing loss.

• A profound hearing loss means that you may not hear loud speech or any speech at all. – You are forced to rely on visual cues instead of

hearing as your main method of communication. This may include sign-language and/or speechreading (also commonly referred to as "lipreading")

• Children have more sensitive ears than adults. They can recognize a wider variety of noises.

• Dolphins have the best sense of hearing among animals. They are able to hear 14 times better than humans.

• Animals hear more sounds than humans.

FUN FACT

• Decibels (dB)- the intensity (volume or

loudness) of a sound– A whisper is about 20 dB– loud music (some concerts) is around 80 to

120 dB– and a jet engine is about 140 to 180 dB– Usually, sounds greater than 85 dB can cause

hearing loss in a few hours; louder sounds can cause immediate pain, and hearing loss can develop in a very short time

How Hearing Loss is Measured• Hertz- a range of frequencies• The tone of sound is measured in cycles per second

(cps) or Hertz. • Low bass tones range around 50 to 60 Hz• Shrill, high - pitched tones range around 10,000 Hz

or higher• The normal range of human hearing is about 20 Hz

to 20,000 Hz• Some people can hear within a slightly higher range• Animals can hear up to about 50,000 Hz.

Identifying Hearing Loss

• Ranges have been established to help people identify how much difficulty they should expect from their hearing loss. The typical ranges for an adult are:

• -10dB to 25dB = Normal range• 26dB to 40 dB = Mild hearing loss• 41 dB to 55 dB = Moderate hearing loss• 56 dB to 70 dB = Moderately Severe hearing loss• 71 dB to 90 dB = Severe hearing loss• over 90 dB = Profound hearing loss

Audiogram• Hearing loss is plotted on an audiogram• Right ear is represented by a red circle• Left ear is represented by a blue X

Audiogram• 10dB to 25dB =

Normal hearing• 26dB to 40 dB =

Mild hearing loss • 41 dB to 55 dB =

Moderate hearing loss • 56 dB to 70 dB =

Moderately-Severe loss • 71 dB to 90 dB =

Severe hearing loss• over 90 dB =

Profound hearing loss

Decibels

Hertz

Hertz/Decibels

Identify the Hearing Loss

What type of hearing loss

is it?

Normal Hearing

Mild Hearing Loss

Moderate Loss

Profound Hearing Loss

Unilateral Hearing Loss

Speech Banana

Ear Conditions• Earache: Pain in the ear can have many causes. Some

of these are serious, some are not serious.• Otitis media (middle ear inflammation): Inflammation

or infection of the middle ear (behind the eardrum). Usually, this is caused by an infection.

• Swimmer’s ear (Otitis externa): Inflammation or infection of the outer ear (pinna and ear canal). Sudden cases are usually infections; chronic otitis is often a skin condition (dermatitis).

Ear Conditions

• Meniere’s disease: A condition in which the inner ear on one side malfunctions. Vertigo, tinnitus, hearing loss, and pain are common symptoms.

• Tinnitus: Ringing in one or both ears. Usually this is due to damage from noise exposure, or from aging.

• Cerumen (ear wax) impaction: Ear wax may block the ear canal and adhere to the eardrum. The eardrum’s reduced vibrations impair hearing.

Ear Conditions

• Ruptured eardrum: Very loud noises, sudden changes in air pressure, or foreign objects can tear the eardrum. The small hole usually heals within a few weeks.

• Acoustic neuroma: A noncancerous tumor that grows on the nerve traveling from the ear to the brain. Hearing loss, vertigo, and tinnitus can be symptoms.

• Mastoiditis: Infection of the mastoid bone, just behind the ear. Mastoiditis was once a common complication of untreated ear infections.

Ear Conditions

• Benign paroxysmal positional vertigo (BPPV): A disruption of function in the inner ear, causing episodes of vertigo. Although not medically serious, its symptoms can be distressing.

• Cholesteatoma: This is a benign condition. It is the buildup of fibrous tissue within the middle ear and surrounding bones. Often there is a foul smelling discharge associated with hearing loss.