The adrenal glands produce hormones that help control the heart rate, blood pressure, the way the body uses food, and other vital functions. The adrenal cortex secretes steroid (cortisone-related) hormones and mineralocortoids that regulate the levels of minerals such as sodium and potassium in the blood.
The adrenal medulla makes adrenaline (adrenaline) and noradrenaline (noradrenaline). Adrenaline is secreted in response to low blood levels of glucose as well as exercise and stress; it causes the breakdown of the storage product glycogen to the sugar glucose in the liver, facilitates the release of fatty acids from adipose (fat) tissue, causes dilation (widening) of the small arteries within muscle and increases the output of the heart. Noradrenaline is a neurohormone, a neurotransmitter, for of most of the so-called sympathetic nervous system.
The name "adrenal" comes from the Latin "ad-", toward + "rebes", kidney. It refers to the perch of this gland atop the kidney. The adrenals are also called the suprarenal glands, "supra-" in Latin meaning "on top."
Alkaline phosphatase: An enzyme made in the liver, bone, and the placenta and normally present in high concentrations in growing bone and in bile. Alkaline phosphatase is released into the blood during injury and during such normal activities as bone growth and pregnancy. It is measured in a routine blood test.
Abnormally high blood levels of alkaline phosphatase may indicate disease in bone or liver, bile duct obstruction, or certain malignancies. The enzyme is often elevated in the leukemic cells in chronic myelogenous leukemia.
Abnormally low levels of alkaline phosphatase is a genetic condition called hypophosphatasia which results in bone deformities.
The enzyme is termed alkaline phosphatase because it works under alkaline (non-acidic) conditions, as opposed to acid phosphatase.
Amino acid: One of the 20 building blocks of protein. The sequence of amino acids in a protein and, hence, the function of that protein are determined by the genetic code in the DNA.
Amino acids are molecules that (in technical terms) contain a basic amino (NH2) group, an acidic carboxyl (COOH) group and a side chain attached to an alpha carbon atom.
The 20 amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine.
The term "amino acids" dates to the middle of the 19th century. The idea that amino acids are "Bausteine" (building stones) came from the Nobel Prize winning German biochemist Albrecht Kossel (1853-1927).
Anemia: The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.Examples of bacteria include:
The term bacteria was devised in the 19th century by the German botanist Ferdinand Cohn (1828-98) who based it on the Greek bakterion meaning a small rod or staff. In 1853, Cohn categorised bacteria as one of three types of microorganisms -- bacteria (short rods), bacilli (longer rods), and spirilla (spiral forms). The term bacteria was preceded in the 17th century by the microscopic animalcules described by Antony van Leeuwenhoek (1632-1723).
Blood pH: The acidity or alkalinity of blood. The pH of any fluid is the measure of the hydrogen ion (H-) concentration. A pH of 7 is neutral. The lower the pH, the more acidic the blood. A variety of factors affect blood pH including what is ingested, vomiting, diarrhea, lung function, endocrine function, kidney function, and urinary tract infection. The normal blood pH is tightly regulated between 7.35 and 7.45.
Caffeine: A stimulant found naturally in coffee beans, tea leaves, cocoa beans (chocolate) and kola nuts (cola) and added to soft drinks, foods, and medicines. A cup of coffee has 100-250 milligrams of caffeine. Black tea brewed for 4 minutes has 40-100 milligrams. Green tea has one-third as much caffeine as black tea.
Caffeine is an alkaloid. It is metabolized in the liver and the breakdown products of caffeine are excreted through the kidney. In women on oral contraceptives, the rate at which they clear caffeine from the body is considerably slower. Pregnancy reduces a woman's ability to process caffeine still further. The half life of caffeine in an adult is about 3 to 4 hours. In pregnancy, it is 18 hours.
In doses of 100-200 mg. caffeine can increase alertness, relieve drowsiness and improve thinking. At doses of 250-700 mg/day, caffeine can cause anxiety, insomnia, nervousness, hypertension, and insomnia. Caffeine is a diuretic and increases urination. It can curiously enough make it more difficult to lose weight because it stimulates insulin secretion, which reduces serum glucose, which increases hunger.
Caffeine can help relieve some headaches, so a number of over-the-counter and prescription pain relievers include it as an ingredient, usually with aspirin or another analgesic.
The word "caffeine" came from the German Kaffee and the French cafe meaning, of course, coffee.
Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
Cancer is not one disease. It is a group of more than 100 different and distinctive diseases.
Cancer can involve any tissue of the body and have many different forms in each body area. Most cancers are named for the type of cell or organ in which they start. If a cancer spreads (metastasizes), the new tumor bears the same name as the original (primary) tumor.
The frequency of a particular cancer may depend on gender. While skin cancer is the most common type of malignancy for both men and women, the second most common type in men is prostate cancer and in women, breast cancer.
Cancer frequency does not equate to cancer mortality. Skin cancers are often curable. Lung cancer is the leading cause of death from cancer for both men and women in the United States today.
Benign tumors are NOT cancer; malignant tumors are cancer. Cancer is NOT contagious.
Cancer is the Latin word for crab. The ancients used the word to mean a malignancy, doubtless because of the crab-like tenacity a malignant tumor sometimes seems to show in grasping the tissues it invades. Cancer may also be called malignancy, a malignant tumor, or a neoplasm (literally, a new growth).
CAT scan: Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them in pictures on a screen. The CAT (computerized axial tomography) scan can reveal some soft-tissue and other structures that cannot even be seen in conventional X-rays. Using the same dosage of radiation as that of an ordinary X-ray machine, an entire slice of the body can be made visible with about 100 times more clarity with the CAT scan.
The "cuts" (tomograms) for the CAT scan are usually made 5 or 10 mm apart. The CAT machine rotates 180 degrees around the patient's body; hence, the term "axial." The machine sends out a thin X-ray beam at 160 different points. Crystals positioned at the opposite points of the beam pick up and record the absorption rates of the varying thicknesses of tissue and bone. The data are then relayed to a computer that turns the information into a 2-dimensional cross-sectional image.
CAT scanning is painless. Iodine-containing contrast material is sometimes used in CAT scanning. If you are having a CAT scan and are allergic to iodine or other radiocontrast materials, please notify your doctor and the radiology staff.
CAT scanning was invented in 1972 by the British engineer Godfrey N. Hounsfield (later Sir Godfrey) and the South African (later American) physicist Alan Cormack. CAT scanning was already in general use by 1979, the year Hounsfield and Cormack were awarded the Nobel Prize in Medicine or Physiology for its development.
The CAT scan is also known as the CT (computerized tomography) scan.
Cholesterol: The most common type of steroid in the body, cholesterol has gotten something of a bad name. However, cholesterol is a critically important molecule.
It is essential to the formation of:
Cholesterol is also necessary to the normal permeability and function of cell membranes, the membranes that surround cells.
Cholesterol is carried in the bloodstream as lipoproteins. Low-density lipoprotein (LDL) cholesterol is the "bad" cholesterol because elevated LDL levels are associated with an increased risk of coronary artery (heart) disease. Conversely, high-density lipoprotein (HDL) cholesterol is the "good" cholesterol since high HDL levels are associated with less coronary disease.
After the age of 20, cholesterol testing is recommended every 5 years.
A diet high in saturated fats tends to increase the blood cholesterol levels while diets high in unsaturated fats tend to do the opposite, to lower blood cholesterol levels.
Although some cholesterol is obtained from the diet, most cholesterol is made in the liver and other tissues. The treatment of elevated cholesterol therefore involves not only diet but also weight loss and regular exercise (and, occasionally, medications).
Dementia: Significant loss of intellectual abilities such as memory capacity, severe enough to interfere with social or occupational functioning.
Criteria for the diagnosis of dementia include impairment of attention, orientation, memory, judgment, language, motor and spatial skills, and function. By definition, dementia is not due to major depression or schizophrenia.
Dementia is reported in as many as 1% of adults 60 years of age. It has been estimated that the frequency of dementia doubles every five years after 60 years of age.
Alzheimer's disease is the most common cause of dementia. There are many other causes of dementia, including (in alphabetical order): AIDS (due to HIV infection), alcoholism (the dementia is due to thiamine deficiency), brain injury, brain tumors, Creutzfeldt-Jakob disease, dementia with Lewy bodies (tiny round structures made of proteins that develop within nerve cells in the brain), drug toxicity, encephalitis, meningitis, Pick disease (a slowly progressive deterioration of social skills and changes in personality leading to impairment of intellect, memory, and language), syphilis, thyroid disease (hypothyroidism) and vascular dementia (damage to the blood vessels leading to the brain).
Detox: Short for detoxification, usually from an addictive drug such as alcohol or heroin. A detox center is designed to promote the recovery of a person from an addiction.
Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus. Diabetes mellitus and diabetes insipidus share the name "diabetes" because they are both conditions characterized by excessive urination (polyuria).
The word "diabetes" is borrowed from the Greek word meaning "a siphon." The 2nd-century A.D. Greek physician, Aretus the Cappadocian, named the condition "diabetes." He explained that patients with it had polyuria and "passed water like a siphon."
When "diabetes" is used alone, it refers to diabetes mellitus. The two main types of diabetes mellitus -- insulin-requiring type 1 diabetes and adult-onset type 2 diabetes -- are distinct and different diseases in themselves.
For information in depth, see:
Disease: Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the rubella (German measles) virus.Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosemia, an error in the handling (metabolism) of the sugar galactose.
Folic acid: One of the B vitamins that is a key factor in the synthesis (the making) of nucleic acid (DNA and RNA).
A deficiency of folic acid after birth causes a kind of anemia, namely, megaloblastic anemia in which there is a paucity of red blood cells and those that are made are unusually large and immature (so-called blast cells).
Lack of adequate folic acid during pregnancy was first found to increase the risk for the baby to have a birth defect involving the spinal cord and brain -- a neural tube defect such as spina bifida (meningomyelocele) or anencephaly.
The association was then investigated between the mother's use of drugs that act as folic acid antagonists in the first trimester of pregnancy and the birth of a child with a congenital malformation (birth defect). It was found that folic acid antagonists increased the risk not only of neural tube defects but also of congenital heart malformations, cleft lip and palate , and urinary tract defects. Folic acid. it now is clear, reduces the risks for a remarkably broad gamut of birth defects.
In order for folic acid to be effective in preventing these birth defects, the vitamin must be consumed every day beginning before conception and continuing through the first three months of pregnancy. Educating women (and their doctors) about the importance of folic acid is going to require a major effort. According to one study, only 10% of women know that folic acid should be taken before pregnancy.
An adequate intake of folic acid appears important to the health of arteries, reducing the risk of second heart attacks and strokes (it may do so by lowering the level of homocysteine). Folic acid also may lower the risk of stomach cancer.
GERD: Stands for Gastroesophageal Reflux Disease, a disorder in which there is recurrent return of stomach contents back up into the esophagus, frequently causing heartburn, a symptom of irritation of the esophagus by stomach acid. This can lead to scarring and stricture of the esophagus, which can require stretching (dilating)
Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
Many hormones are secreted by specialized glands such as the thyroid gland. Hormones are essential for every activity of daily living, including the processes of digestion, metabolism, growth, reproduction, and mood control. Many hormones, such as the neurotransmitters, are active in more than one physical process.
Examples of hormones include aldosterone, antidiuretic hormone(ADH), cortisol, erythropoietin, estrogen, human chorionic gonadotropin (hCG), parathormone, progesterone, and testosterone.
A hormone originally denoted a chemical made by a gland for export to another part of the body. Now a hormone is more broadly any chemical, irrespective of whether it is produced by a special gland or not, for export or domestic use, that "controls and regulates the activity of certain cells or organs.". The word "hormao" which means "I set in motion" or "I stir up" was used in ancient Greece to covey the "vital principle" of "getting the juices flowing." The word "hormone" was resurrected in 1902 (not 1906, as the Oxford English Dictionary states) by the English physiologists Wm. M. Bayliss and Ernest H. Starling who that year reported their discovery of a substance made by glands in the small intestine that stimulated pancreatic secretion. They called the substance "secretin" and dubbed it a "hormone", the first known hormone.
Iron: An essential mineral. Iron is necessary for the transport of oxygen (via hemoglobin in red blood cells) and for oxidation by cells (via cytochrome). Deficiency of iron is a common cause of anemia. Food sources of iron include meat, poultry, eggs, vegetables and cereals (especially those fortified with iron). According to the National Academy of Sciences, the Recommended Dietary Allowances of iron are 15 milligrams per day for women and 10 milligrams per day for men. Iron overload can damage the heart, liver, gonads and other organs. Iron overload is a particular risk in people who may have certain genetic conditions (hemochromatosis) sometimes without knowing it and also in people receiving recurrent blood transfusions. Iron supplements meant for adults (such as pregnant women) are a major cause of poisoning in children.
Laser: A powerful beam of light that can produce intense heat when focused at close range. Lasers are used in medicine in microsurgery, cauterization, for diagnostic purposes, etc. For example, lasers are employed in microsurgery to cut tissue and remove tissue.
Technical Note: A laser concentrates high energies into an intense narrow beam of nondivergent monochromatic electromagnetic radiation; Lasers using various substances (ruby, argon, krypton, neodymium, helium-neon, carbon dioxide) are available.
Laser is an acronym coined in 1960 from a forgettable term: Light Amplification by Stimulated Emission of Radiation.
