Headache

-
Headache, pain in any part of the head. Although the condition is widespread, less than 1 percent of all headaches indicate serious physical problems. This small percentage includes headaches caused by, or occurring after, concussion or injury to the head (see Concussion of the Brain), meningitis, encephalitis, stroke, or brain tumors. Headache may also accompany misalignment of the jaw or teeth. Short-lived headaches may occur after eating very cold foods or foods high in nitrites or monosodium glutamate. Caffeine withdrawal also may provoke headaches.

The majority of headaches belong to one of three main groups: migraine, a recurrent, severe headache, usually with throbbing on one side, accompanied by nausea and sometimes impaired vision; cluster, similar to migraine, but of short duration, occurring daily in series over weeks or months and predominantly in the area of one eye; and tension, a headache without consistent location thought to result from contractions of the face, scalp, or neck muscles.

Headaches are so common, and sometimes so difficult to alleviate, that several major clinics are devoted solely to their treatment. Most tension headaches respond to mild analgesics such as aspirin and acetaminophen. Severe migraine and cluster headaches do not respond to aspirin, but can be relieved by a variety of medications that affect the expansion or contraction of blood vessels. Headaches of all three major categories have been relieved in many cases with biofeedback techniques.

Comments

Post a Comment

Popular posts from this blog

Cream, Butter, and Ice Cream

-
. In order for a product to be labeled as cream, it must contain 18 percent milk fat or more. Light whipping cream must contain at least 30 percent fat, and 36 percent fat is the minimum fat content for heavy whipping cream. Half-and-half, an equal mixture of both milk and cream, must have at least 10.5 percent fat. The various grades of cream are valued for their smooth, thick texture. They are often used in cooking instead of milk, because they are less likely to form a skin when heated and can be whipped into a stiff foam. When chilled cream is churned gently, the fat globules gather together to form butter, leaving buttermilk as the by-product. Butter contains at least 82.5 percent fat. In the past, before the advent of widespread refrigeration, salt was added to butter to retard bacterial spoilage; now salt is added mainly for flavor. Ice cream, a popular frozen dessert, is made of milk, cream, sugar, and flavoring. The mixture is slowly beaten while chilled until it is partially ...
Read more

Deoxyribonucleic Acid

-
Deoxyribonucleic Acid (DNA), genetic material of all cellular organisms and most viruses. DNA carries the information needed to direct protein synthesis and replication. Protein synthesis is the production of the proteins needed by the cell or virus for its activities and development. Replication is the process by which DNA copies itself for each descendant cell or virus, passing on the information needed for protein synthesis. In most cellular organisms, DNA is organized on chromosomes located in the nucleus of the cell .
Read more

Bacteria

-
Bacteria is a one-celled organisms visible only through a microscope. Bacteria live all around us and within us. The air is filled with bacteria, and they have even entered outer space in spacecraft. Bacteria live in the deepest parts of the ocean and deep within Earth. They are in the soil, in our food, and on plants and animals. Even our bodies are home to many different kinds of bacteria. Our lives are closely intertwined with theirs, and the health of our planet depends very much on their activities. Bacterial cells are so small that scientists measure them in units called micrometers (µm). One micrometer equals a millionth of a meter (0.0000001 m or about 0.000039 in), and an average bacterium is about one micrometer long. Hundreds of thousands of bacteria would fit on a rounded dot made by a pencil. Bacteria lack a true nucleus, a feature that distinguishes them from plant and animal cells. In plants and animals the saclike nucleus carries genetic material in the form of deoxyrib...
Read more