3.03 Understand the sensory system

“Scrub In”

What is the function of cerumen?

a. Keeps the ear canal from collapsing

b. Helps transmit sound waves

c. Protection

d. Lubrication

Which part of the ear collects sound waves and directs

them into the auditory canal?

a. Pinna

b. Cohlea

c. Tympanic membrane

d. Malleus 3.04 Understand the functions and

disorders of the sensory system 1

3.04 Functions and

disorders of the ear

3.04 Understand the functions and



disorders of the sensory system



Essential Questions

• What are the functions of the sensory system?

• What are some disorders of the sensory system?

• How are sensory system disorders treated?

• How do you relate the body’s communication to

the sensory system?

Understanding the

functions of the ear:

Hearing



Understanding the

functions of the ear External ear Pinna - collects sound

waves External auditory canal -

provides a passageway for sound traveling to the eardrum. It also protects the ear from infection. Contains cerumen (earwax)

– protects the ear

Tympanic membrane (eardrum)- carries sound vibrations to the middle ear



Understanding the

functions of the ear

Middle ear

Ossicles – transmit sound waves from the ear drum to the inner ear

Eustachian tube – equalizes pressure in the middle ear with outside atmosphere



Understanding the

functions of the ear Inner ear

Cochlea – is filled with fluid that vibrates when sound waves are transmitted by the stapes

Semicircular canals – located within the cochlea. contain liquid that is set in motion by head and body movements – impulses sent to cerebellum to help maintain balance (equilibrium)



Understanding the

functions of the ear Pathway of hearing

external auditory canal→

tympanic membrane→

ossicles

(malleus,incus,stapes)→

cochlea→auditory nerve

Decibels -

measure sound based on

human hearing



Understanding the




Process of hearing:

Sound waves enter the auditory canal and

strike the eardrum, causing it to vibrate.

The sound waves are then sent to the inner

ear causing the stapes to vibrate which sets

in motion the fluid of the cochlea. The

alternating pressure changes disturb the

delicate cells in the organ of Corti, moving

the hair cells. This movement stimulates the

sensory hair cells to transmit impulses

through the auditory nerve to the brain.

Healthy Hearing



How do you protect your hearing?

What is the relevance to healthy hearing?

Understanding the


Sound Activity

What is a sound byte?



Short bit of sound or clip from a

longer recording.

Disorders of the ear






Disorders of the ear External otitis (Swimmer's ear)

- infection of the ear canal that can be

caused by many different types of bacteria or

fungi.



Causes: ears that are exposed to

moisture.

Prevention: preventative ear drop

solution, ear plug when you bathe or

swim, drying ear canal with

hairdryer

Disorders of the ear Otitis media

Infection of the middle ear

Often a complication of a

common cold in children due to

their eustachian tube being

shorter and at more of a

horizontal angle than adults.

Treatment: antibiotics; if

chronic or fluid builds up – can

do a Myringotomy (opening in

the ear drum) with tubes

inserted to relieve pressure 15

http://www.entusa.com/ear_photographs_html/normal-eardrum-5.htm

http://www.entusa.com/ear_photographs_html/retracted_eardrum_myringostapediopexy-8.htm

http://www.entusa.com/ear_photographs_html/eardrum_serous_otitis_media-2.htm


Otosclerosis

Inherited disorder in which the

stapes bone first becomes

spongy then hardens. This

causes the stapes to become

unmovable.

Oto- sclerosis

Treatment: stapedectomy

(total replacement of the

stapes)



Disorders of the ear Meniere’s disease

Condition that affects the

semicircular canals of the inner ear

Symptoms: vertigo (dizziness),

nausea, vomiting and tinnitus

(ringing in the ear)

Cause: unknown

Treatment – bed rest, medication

to relieve vertigo and nausea




Tinnitus

Ringing in the ear

Explain this statement:

Tinnitus is a symptom,

not a disorder.




Presbycusis

Condition that

causes deafness

due to the aging

process

Treatment:

hearing aids



Disorders of the ear Conductive hearing loss – sounds

to the inner ear are blocked by ear

wax or there is fluid in the middle

ear

Treatment: clean out ear wax ,

medication to help with fluid behind

TM

Sensorineural hearing loss –

damage to parts of the inner ear or

auditory nerve

Treatment: cochlear implants



Testing for hearing loss

21

Weber test Rinne test

Compares air and bone conduction

hearing. Strike a tuning fork softly, place the

vibrating tuning fork on the base of the

mastoid bone, ask patient to tell you when

the sound is no longer heard.

Distinguishes between

conductive and sensorineural

hearing. Strike a tuning fork softly, place

the vibrating fork on the middle of

the client's head, ask patient if the

sound is heard better in one ear or

the same in both ears

Testing for hearing loss



Weber test: if normal, the

sound is symmetrical

with no lateralization

Rinne test: if normal

patient will note air

conduction twice as long

as bone conduction

Normal results of Rinne and Weber test:

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3.03 Understand the sensory system