Page 97 - 84 human physiolofy part-1

Senses

can be described as the detection of acceleration.

It is determined by the level of fluid properly called endolymph in the labyrinth - a complex set of
tubing in the inner ear.

When the sense of balance is interrupted it causes dizziness, disorientation and nausea.

You can temporarily disturb your sense of balance by closing your eyes and turning rapidly in
circles five or six times. This starts the fluid swirling in circles inside your ear canal. When you stop
turning it takes a few seconds for the fluid to lose momentum, and until then the sense from your inner
ear conflicts with the information coming from your vision, causing dizziness and disorientation. Most
astronauts find that their sense of balance is impaired when in orbit, because there is not enough gravity
to keep the ear's fluid in balance. This causes a form of motion sickness called space sickness.

Disorders with the Ear

Case Study

A 45-year-old woman wakes up not feeling well. She believes that she may be coming down with
the flu due to nausea that she is feeling, so she continues with her day. As the day progresses so does
the feeling of nausea. While watching a movie with members of her family, the sick feeling seems to
intensify and so they leave the movie. In the lobby of the movie theater she becomes very unbalanced
and collapses. The fear is that she is experiencing a stroke. After being taken to the hospital via
ambulance, the ER doctors also feel that it may be a stroke and do CAT scans to verify. Nothing shows
up on the scans but the feeling of nausea and vertigo are intense. The woman is later diagnosed with an
inner ear infection. The next 6-9 months of her life are filled with antibiotics, balance therapy and
continued nausea and vertigo. Nothing seems to help so the doctors go into her inner ear surgically
through her skull. They cut the vestibular nerve that is linked to the balance center on the left side. The
right inner ear will eventually compensate for this loss of balance however it will take months of
balance therapy. After a year from the onset on the inner ear infection, the woman has had three inner
ear surgeries, loss of hearing in the left ear and problems with her balance. Doctors have told her they
have done everything that they can and that she will now have to live with these conditions on a daily
basis.

Deafness
The word deaf can have at least two different meanings. The first term is used to indicate the
presence of enough hearing loss such that an individual is not sensitive to sound. Someone with a
partial loss of hearing is more likely to be referred to as hearing impaired or the qualified partially
deaf. The second term is used to indicate someone who was born without the sense of hearing or
total deafness.

Otitis Media
An inflammation of the middle ear segment. It is usually associated with a buildup of fluid and
frequently causes an earache. The fluid may or may not be infected. The typical progress of otitis
media is: the tissues surrounding the Eustachian tube swell due to an infection and/or severe
congestion. The Eustachian tube remains blocked most of the time. The air present in the middle
ear is slowly absorbed into the surrounding tissues. A strong negative pressure creates a vacuum

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