Download The Anatomy of the Ear - Northside Middle School

The
Anatomy
of the
Ear
The Outer Ear
The outer ear consist of the auricle, auditory canal, and the
eardrum’s outer layer.
Auricle – the external cartilage of the ear that is covered by
skin and located at opposite sides of the head, helps
capture sound
Auditory Canal – is sometimes referred to as the ear canal, funnels
sound to the eardrum
Eardrum Outer Layer – is also called the tympanic membrane
The outer ear collects sound from the external environment. Then the
sound travels through the auditory canal and ends at the tympanic
membrane.
The Middle Ear
The middle ear consists of the eardrum, tympanic cavity, and
the ossicles.
Eardrum – its function is to transmit sound from the air to the
ossicles inside the middle ear
Tympanic Cavity – is a air filled cavity that houses the ossicles
Ossicles – consists of the malleus (hammer), incus (anvil), stapes (stirrup)
Malleus – long handle attached to the eardrum
Incus – the bridge bone between the malleus and the stapes
Stapes –the footplate; the smallest bone in the body
Sound entering the middle ear from the outer ear travels across the eardrum,
causing the ossicles to vibrate. As the ossicles vibrate the sound changes
from air to liquid and is amplified. The middle ear is surrounded by the
mastoid bone.
The Inner Ear
The inner ear consists of the oval window, semicircular ducts,
cochlea, and the auditory tube.
Oval Window – connects the middle ear with the inner ear
Semicircular Ducts – filled with fluid, attaches the cochlea and the
nerves; it sends information on balance and head position to the brain
Cochlea – spiral-shaped organ of hearing; transforms sound into signals that get
sent to the brain
Auditory Tube – drains the fluid from the middle ear into the throat behind the nose
When the stapes moves, it pushes on the oval window, which then in turn moves
the cochlea. The cochlea transforms the fluid vibration of sound from the
semicircular ducts and translates this into signals that are then sent to the brain via
nerves such as the vestibular nerve and the cochlear nerve.
How Does Sound Travel Through
the Ear?
How the ear hears sounds

The ear actually functions as a analysis device, with the mechanism
of the inner ear converting mechanical waves into electrical
impulses.

These impulses describes the intensity of the sound.

Low frequencies are able to mask higher frequencies better.
Deaf Testing
Most people are tested as baby for deaf testing by using either the
Auditory Brainstem Response, Optoacoustic Emissions (individual parts
of ear), or the Brain Audiometry evaluation (all parts of ear).
To test your hearing as an adult the doctors will perform a musical test
to see if you are tone deaf.
Ear Wax

Ear Wax protects the skin of your ear canal, also assists in cleaning
your ear.

Ear Wax offers protection from bacteria, fungi, insects, and water.

When your glands produce too much ear wax it can get hard and
cause a blockage, which could lead to temporary hearing loss.

Signs of an Ear Wax Blockage include partial hearing loss, tinnitus, a
feeling of fullness in the ear, or an ear ache.
How to clean the Ears

Wash the external ear with a cloth, do not insert anything into the
ear canal

If you insert anything into the ear canal you could possibly cause a
blockage of the ear.

To clean the ear out you want to use drops of mineral oils, baby oils,
glycerin or commercial ear drops.

To soften the wax, then you can use a warm saline solution and a
syringe to drive the wax out.
Ear Candling
How It Works

You tilt your head to the side

You insert one end of the candle into your ear canal

You light the opposite end of the candle from your head

Then you ear is filled with warm smoke

You can hear popping and crackling sounds

You let the candle burn until it is 4 inches from your head

This is thought to help with ear health
Ear Candling
Pros
Cons

It is a holistic approach to treating
ear problems

In some cases no ear wax is
removed

These problems include ear wax
build up

Should be done with care to
prevent injury

Can help sinus and ear irritation,
tinnitus, and can help to relieve
pressure in the ears

It is not approved by the Food and
Drug Administration
Hearing Aids

A hearing aid is a device that increases the loudness of sound for
the wearer.

The hearing aid can amplify sound with in a range of 400 to 4,000
hertz.

If the sound falls outside of this range the wearer will experience
difficulty understanding the sound.
Cochlear Implants
What is it?

An implant that provides direct electrical stimulation to the auditory
nerve in the inner ear.
How does it work?

Cochlear Implants that have external and internal parts.

The parts are implanted surgically implanted together
to allow the user to hear sound.

The external part gathers sound information and then
sends this information to the internal part.
Ear Defects

Micortica – a condition in which the external portion of the ear (the auricle) is
malformed

Anotia – the total absence of the auricle most often with narrowing or absence
or the external auditory meatus
All of these can be grouped into four types according to the level of affiliation.

Type 1 – the external ear is small and the auricle retains most of its normal
structure

Type 2 – the external ear is moderately analogous, hooked or “S” shaped in
appearance

Type 3 – the external is a rudimentary soft tissue structure with no cartilage

Type 4 – all of the external ear structures are absent
Tinnitus

Tinnitus is categorized as ringing in the ear and other ear
abnormalities.

People with tinnitus will hear ringing, buzzing, humming, roaring, and
other sounds when there is no actual sound present.
Ear Infection
An ear infection occurs when one of your Eustachian tubes becomes
swollen or blocked. This causes fluid to build up in your inner ear,
causing the infection.
Méniére’s Disease

A condition that affects the inner ear.

Causes attacks of dizziness, nausea, vomiting, and some hearing
loss.

The cause of this disease is unknown, however it is believed to be
related to having too much fluid in the inner ear.
Otitis Media

This is a middle ear infection.

It is most common in infants and younger children.

It is usually caused by a viruses and bacteria that live in the throat
and travel to the middle ear via the Eustachian tube.