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  Ear



Ear

   The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain.

RELATED TERMS
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Hearing
The sensation of sound.

Organ
A structural unit of an animal or plant that serves a specific function.

Ear
The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain.

Anatomy
The study of form. Gross anatomy involves structures that can be seen with the naked eye. It is as opposed to microscopic anatomy (or histology) which involves structures seen under the microscope.

Brain
"That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called ""hemispheres."" "

Cortex
The outer layer of the cerebrum, densely packed with nerve cells.

Nerve
Tissue that conveys sensation, temperature, position information to the brain.



SIMILAR TERMS
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E coli
Short for Escherichia coli, the colon bacillus, a bacterium that normally resides in the human colon. E. coli has been studied intensively in genetics and molecular and cell biology because of its availability, its small genome size, its normal lack of pathogenicity (disease-causing ability), and its ease of growth in the laboratory. Most strains of E coli are quite harmless. However, some strains of E. coli are capable of causing disease, sometimes disease of deadly proportions. For example, an outbreak of E. coli O157:H7 bacteria in the water supply hit Walkerton, Ontario in the year 2000; the E. coli affected about 2,000 people in and around Walkerton and were responsible for the deaths of some 18 people.

E coli hemorrhagic diarrhea
Bloody colitis (inflammation of the bowel) caused by E. coli, usually by the strain E. coli 0157:H7. The diarrhea is severe with painful abdominal cramps, gross blood in the stool, and lasts for 6 to 8 days. Most commonly, E. coli 01257:H7 comes from eating raw or undercooked ground beef (hamburger) or from drinking raw milk or contaminated water. Less commonly, E coli O157:H7 can be transmitted from one person to another.

E coli O157:H7
"A dangerous form of Escherichia coli, the colon bacillus, a bacterium that normally lives in the human colon. E. coli 0157:H7 is a major health problem, causing hemorrhagic colitis, the hemolytic-uremic syndrome, and thrombotic thrombocytopenic purpura: Hemorrhagic colitis -- E coli O157:H7 causes about 20,000 cases of hemorrhagic colitis (bloody inflammation of the colon) a year in the US. The bacteria produce toxins that can damage the lining of the intestine. The colitis caused can be quite severe with painful abdominal cramps, diarrhea and grossly visible blood in the stool, lasting for 6 to 8 days. Hemolytic-uremic syndrome (HUS) -- Some children infected with E. coli 0157:H7 develop the hemolytic-uremic syndrome (HUS). Hemolytic"" refers to the breakup of red blood cells. This leads to anemia and a shortage of platelets (thrombocytopenia) which causes abnormal bleeding. ""Uremic"" refers to the acute kidney failure. Central nervous system problems with seizures and coma can also occur. The hemolytic-uremic syndrome (HUS) is the most common cause of acute kidney failure in infants and young children. Thrombotic thrombocytopenic purpura (TTP) -- Persons who get E. coli 0157:H7, particularly the elderly, can develop a syndrome similar to HUS called thrombotic thrombocytopenic purpura (TTP) with anemia due to fragmentation of red blood cells, shortage of platelets (thrombocytopenia) with easy bruising, neurologic abnormalities, impaired kidney function, and fever.

E2F3
E2F transcription factor 3. E2F3 is a gene on chromosome 6p22 that is a member of the E2F family of transcription factors. E2F3 may be a key gene in modulating the aggressivity of prostate cancer. E2F3 is present in a high proportion (67%) of prostate cancers. Men with prostate cancer exhibiting detectable E2F3 expression have poorer survival than those without detectable E2F3 expression.

Eagle syndrome
Inflammation of the styloid process, a spike-like projection sticking off the base of the skull. The tissues in the throat rub on this structure during the act of swallowing causing pain. The diagnosis of Eagle syndrome is made by history and an x-ray showing the abnormal styloid process. Anti-inflammatory drugs are the first line of treatment although surgical removal of the styloid process may be needed.

Ear

Ear bones
The malleus, incus, and stapes.

Ear canal, self-cleaning
Most of the time the ear canals are self-cleaning, that is, there is a slow and orderly migration of ear canal skin from the eardrum to the outer opening. Old earwax is constantly being transported from the deeper areas of the ear canal to the opening where it usually dries, flakes, and falls out.

Ear cleaning (by a doctor)
When so much wax accumulates that it blocks the ear canal (and hearing), your physician may have to wash it out, vacuum it, or remove it with special instruments. Alternatively, your physician may prescribe ear drops what are designed to soften the wax (such as Cerumenex).

Ear cleaning (yourself)
Never put anything smaller than your elbow in your ear! Wax is not formed in the deep part of the ear canal near the eardrum, but only in the outer part of the canal. So when a patient has wax pushed up against the eardrum, it is often because he has been probing his ear with such things as cotton-tipped swabs (such as Q-Tips), bobby pins, or twisted napkin corners. Such objects only serve as ramrods to push the wax in deeper. Also, the skin of the ear canal and the eardrum is very thin, fragile and easily injured. The ear canal is more prone to infection after it has been whipped clean of the "good" coating type wax. In addition, we have seen many perforated eardrums as a result of these efforts.

Ear infection, middle (acute)
Acute middle ear infection, medically called acute otitis media is inflammation of the middle ear. Acute otitis media typically causes fluid in the middle ear accompanied by signs or symptoms of ear infection: a bulging eardrum usually accompanied by pain; or a perforated eardrum, often with drainage of purulent material (pus).

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