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 vibration2. Ear Tudes

Ear TubesEar 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 Aidssound waves are amplified

Treating Nerve Deafness??????

Conductive deafnessvs

Nerve DeafnessWhich part of the ear?

How treatable are they?

Which occurs in old age?

Deaf community and blind community mixed reaction to cures.

WHY?