Download Ear Tubes

The Ear
Chapter 12
Text Book
Sense Organs (EAR) (Pages 414-416)
•Describe the general structure and function of the ear.
Include: (i) tympanic membrane (ii) ossicles (i.e., malleus, incus, stapes) (iii)
eustachian tube (iv) semi-circular canals (v) cochlea
•Analyze and describe examples of disorders of the ear
and where technologies for the correction of auditory
defects were developed based on scientific
understanding. Include ear disorders – conduction deafness, nerve
deafness.
•Describe treatments for ear disorders - Eustachian tube
implants, hearing aids
•Evaluate, considering ethical issues, the consequences
of medical treatments for visual and auditory disorders.
Include sense of exclusion and mandatory organ donation.
Hearing & the Cerebrum p. 399
Parts of the EAR
(i) tympanic membrane (ii) ossicles (i.e., malleus, incus,
stapes) (iii) eustachian tube (iv) semi-circular canals (v)
cochlea
Conductive deafness
If the cause of the hearing loss is in the outer or
middle ear, it may create problems with the
transmission (or conduction) of sound through
the ear canal and middle ear. This kind of
hearing loss is called a conductive hearing loss.
A conductive hearing loss may be caused by
wax, fluid, infection or problems with the bones
in the middle ear and can often be treated.
Treating Conductive Deafness
1. Hearing Aid amplifies vibration
2. Ear Tudes
Ear Tubes
Ear tubes are small tubes made out of plastic or metal that are placed into the ear drum
to ventilate the middle ear. The middle ear is, under normal circumstances, filled with air
at the same pressure as the surrounding atmosphere. The pressure is maintained at this
normal level by a natural tube called the eustachian tube. When pressure gets greater or
less in the middle ear (for example, when changing altitudes in a plane) the eustachian
tube opens, causing the ears to "pop" and the pressure to equalize. The eustachian tube
also opens during swallowing, chewing, or other jaw movement without producing the
pronounced popping sensation.
If the eustachian tube is not functioning properly, it will not open. This causes the
pressure in the middle ear to drop. High negative pressure in the middle ear will draw
fluid out from the surrounding tissue and cause fluid to accumulate in the middle ear.
This fluid can become infected, setting the stage for recurrent ear infections (otitis
media). The infection causes swelling, making it even more difficult for the eustachian
tube to open.
Ear tubes are placed to break this cycle, allowing the ears to drain and to ventilate. The
drainage acts in the short term to remove any fluid in the middle ear. The ventilation
function is the more important long term benefit of the tube. With ventilation the lining of
the middle ear can return to normal. Since the pressure in now equalized with the
surrounding air, there is no accumulation of new fluid and the chances of additional
infections is reduced.
These are examples of two type of ear tubes. The diameter and the width of each tube is
about 3 mm (one-eighth inch).
Hearing Aids
sound waves are amplified
Treating Nerve Deafness
??????
Conductive deafness
vs
Nerve Deafness
Which part of the ear?
How treatable are they?
Which occurs in old age?
Deaf community and blind
community mixed reaction to cures.
WHY?