FDA Overview Glossary of TermsThe following are health and medical definitions of terms that appear in the FDA Overview article.
Abdominal: Relating to the abdomen, the belly, that part of the body that contains all of the structures between the chest and the pelvis. The abdomen is separated anatomically from the chest by the diaphragm, the powerful muscle spanning the body cavity below the lungs. Absorb: 1. To take something in, as through the skin or the intestine. Absorption: Uptake. In the biomedical sciences, absorption has diverse specific meanings. Addiction: A chronic relapsing condition characterized by compulsive drug-seeking and abuse and by long-lasting chemical changes in the brain. Addiction is the same irrespective of whether the drug is alcohol, amphetamines, cocaine, heroin, marijuana, or nicotine. Every addictive substance induces pleasant states or relieves distress. Continued use of the addictive substance induces adaptive changes in the brain that lead to tolerance, physical dependence, uncontrollable craving and, all too often, relapse. Dependence is at such a point that stopping is very difficult and causes severe physical and mental reactions from withdrawal. The risk of addiction is in part inherited. Genetic factors, for example, account for about 40% of the risk of alcoholism. The genetic factors predisposing to addiction are not yet fully understood. Adverse event: In pharmacology, any unexpected or dangerous reaction to a drug. Aerosol: 1. In general, a fine mist or spray which contains minute particles. Albumin: The main protein in human blood and the key to the regulation of the osmotic pressure of blood. Chemically, albumin is soluble in water, precipitated by acid, and coagulated by heat. Alkaloid: A member of a large group of chemicals that are made by plants and have nitrogen in them. Many alkaloids possess potent pharmacologic effects. The alkaloids include cocaine, nicotine, strychnine, piperine, caffeine, morphine, pilocarpine, atropine, methamphetamine, mescaline, ephedrine, and tryptamine. Allergen: A substance that is foreign to the body and can cause an allergic reaction in certain people. For examples, pollen, dander, mold. Allergy: A misguided reaction to foreign substances by the immune system, the body system of defense against foreign invaders, particularly pathogens (the agents of infection). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens, dust mite, molds, danders, and certain foods. People prone to allergies are said to be allergic or atopic. Alzheimer disease: See: Alzheimer's disease. American Academy of Pediatrics: AAP. Its member pediatricians "dedicate their efforts and resources to the health, safety and well-being of infants, children, adolescents and young adults." According to the Academy, it had as of 1998 some 53,000 members in the United States, Canada and Latin America. Over 34,000 of them were board-certified and called Fellows of the American Academy of Pediatrics (FAAP). American Medical Association (AMA): The AMA. The AMA's mission statement proclaims: 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: The building blocks of polypeptides and proteins. 
Analogous: In anatomy, similar in appearance or function but otherwise different. Two structures may be analogous if they serve the same purpose but differ evolutionary in origin as, for example, human and insect legs. As compared to homologous. Analysis: A psychology term for processes used to gain understanding of complex emotional or behavioral issues. Anaphylaxis: Allergic reaction. In severe cases, this can include potentially deadly anaphylactic shock. Anthrax: A serious bacterial infection caused by Bacillus anthracis that occurs primarily in animals. Cattle, sheep, horses, mules, and some wild animals are highly susceptible. Humans and swine are generally quite resistant to anthrax. Humans become infected when the spores of B. anthracis enter the body by contact with animals infected with B. anthracis or from contact with contaminated animal products, insect bites, ingestion, or inhalation. Aerosolized ("weaponized") spores of B. anthracis can potentially be used (misused) for biological warfare and bioterrorism. Cutaneous anthrax is the most common form of the disease and is characterized by the development of a localized skin lesion with a central eschar surrounded by marked edema (swelling). Inhalation anthrax (woolsorters' disease) typically involves hemorrhagic mediastinitis (bleeding into the mid-chest), rapidly progressive systemic (bodywide) infection, and carries a very high mortality rate. Gastrointestinal anthrax is much rarer but is also associated with a high mortality rate. Antifungal: A drug used to treat fungal infections. Antimicrobial: A drug used to treat a microbial infection. Antimicrobial resistance: The result of microbes changing in ways that reduce or eliminate the effectiveness of drugs, chemicals, or other agents to cure or prevent infections. Antioxidant: Any substance that reduces oxidative damage (damage due to oxygen) such as that caused by free radicals. Free radicals are highly reactive chemicals that attack molecules by capturing electrons and thus modifying chemical structures. Antitoxin: An antibody capable of destroying microorganisms including viruses and bacteria. Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations, sweating, and feelings of stress. Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated. Aspartame: A man-made sweetener with almost no calories used in place of sugar. Aspirin: A good example of a tradename that entered into the language, Aspirin was once the Bayer trademark for acetylsalicylic acid. Autism: A spectrum of neuropsychiatric disorders characterized by deficits in social interaction and communication, and unusual and repetitive behavior. Some, but not all, people with autism are non-verbal. Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life). Bacterial: Of or pertaining to bacteria. For example, a bacterial lung infection.
Biotechnology: The fusion of biology and technology. Biotechnology is the application of biological techniques to product research and development. In particular, biotechnology involves the use by industry of recombinant DNA, cell fusion, and new bioprocessing techniques. Biotechnology is expected to become increasingly important in the 21st century. Bioterrorism: Terrorism using biologic agents that are harmful to humans. Biological diseases and the agents that might be used for terrorism have been listed by the US Centers for Disease Control and Prevention (CDC). These agents include viruses, bacteria, rickettsiae (microorganisms that have traits common to both bacterial and viruses), fungi, and biological toxins. The biological disease agents are classified into three categories, according to the degree of danger each agent is felt to pose. Blister: A collection of fluid underneath the top layer of skin (epidermis). One that is more than 5 mm in diameter with thin walls and is full of watery fluid is called a bulla or a bleb. There are many causes of blisters including burns, vesicant agents, friction forces, and diseases of the skin. Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension". Botulinum toxin: A toxin produced by the bacterium Clostridium botulinum that is the most poisonous biological substance known. Botulinum toxin acts as a neurotoxin. It binds to the nerve ending at the point where the nerve joins a muscle, blocking the release by the nerve of the chemical acetylcholine (the principal neurotransmitter at the neuromuscular junction), preventing the muscle from contracting. The result is weakness and paralysis of the muscle. The muscle atrophies. The blockage of acetylcholine release is irreversible. Function can be recovered by the sprouting of nerve terminals and the formation of new synaptic contacts, which usually takes 2 to 3 months. Bovine: Having to do with cows and cattle, as in bovine spongiform encephalopathy (mad cow disease), bovine tuberculosis, and bovine growth hormone. Calcium: A mineral found mainly in the hard part of bones, where it is stored. Calcium is added to bones by cells called osteoblasts and is removed from bones by cells called osteoclasts. Calcium is essential for healthy bones. It is also important for muscle contraction, heart action, nervous system maintenance, and normal blood clotting. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1,200 milligrams a day (four glasses of milk) for men and women 51 and older, 1,000 milligrams a day for adults 19 through 50, and 1,300 milligrams a day for children 9 through 18. The upper limit for calcium intake is 2.5 grams daily. Learn more about calcium with evidence-based information on RxList.Calorie: A unit of food energy. In nutrition terms, the word calorie is used instead of the more precise scientific term kilocalorie which represents the amount of energy required to raise the temperature of a liter of water one degree centigrade at sea level. The common usage of the word calorie of food energy is understood to refer to a kilocalorie and actually represents, therefore, 1000 true calories of energy. A calorie is also known as cal, gram calorie, or small calorie. Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread). Capsule: Capsule has many meanings in medicine including the following:
See the entire definition of Capsule Carbohydrate: Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources (calories) by the body. Carbohydrates can also be defined chemically as neutral compounds of carbon, hydrogen and oxygen. Carbohydrates: Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources (calories) by the body. Carbohydrates can also be defined chemically as neutral compounds of carbon, hydrogen and oxygen. Carcinogenic: Causing cancer or contributing to the causation of cancer. Pertaining to a carcinogen. Cardiovascular: The circulatory system comprising the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them. Cardiovascular disease: Disease affecting the heart or blood vessels. Caries: Dental cavities. Holes in the two outer layers of a tooth called the enamel and the dentin. The enamel is the outermost white hard surface and the dentin is the yellow layer just beneath enamel. Both layers serve to protect the inner living tooth tissue called the pulp, where blood vessels and nerves reside. Small cavities may not cause pain, and may be unnoticed by the patient. Larger cavities can collect food, and the inner pulp of the affected tooth can become irritated by bacterial toxins, foods that are cold, hot, sour, or sweet - causing toothache. Carotenoid: One of a group of compounds that includes beta-carotene, alpha-carotene, and beta-cryptoxanthin which are converted to vitamin A and are referred to as provitamin A carotenoids. The sole known role of carotenoids is to act as a source of vitamin A in the diet. Fruits and vegetables are the main source of carotenoids in the human diet. CBER: Center for Biologics Evaluation & Research: Part of the FDA (the US Food & Drug Administration). CDC: The Centers for Disease Control and Prevention, the US agency charged with tracking and investigating public health trends. The stated mission of the CDC is "To promote health and quality of life by preventing and controlling disease, injury, and disability." The CDC is a part of the U.S. Public Health Services (PHS) under the Department of Health and Human Services (HHS). Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane. Centers for Disease Control and Prevention: The US agency charged with tracking and investigating public health trends. The stated mission of the Centers for Disease Control and Prevention, commonly called the CDC, is "To promote health and quality of life by preventing and controlling disease, injury, and disability." 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. Clinical trial: See: Clinical trials. See also: Inconclusive clinical trial; Negative clinical trial; Non-inferior clinical trial; Positive clinical trial. Clinical trials: Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people. Clone: Literally a fragment, the word in modern medical science has come to mean a replica, for example, of a group of bacteria or a macromolecule such as DNA. Clone also refers to an individual developed from a single somatic (non-germ) cell from a parent, representing an exact replica of that parent. A clone is a group of cells derived from a single ancestral cell. Cloning: The process of making a clone, a genetically identical copy. Cloning can refer to the technique of producing a genetically identical copy of an organism by replacing the nucleus of an unfertilized ovum with the nucleus of a body cell from the organism. Cocaine: The most potent stimulant of natural origin, a bitter addictive anesthetic (pain blocker) which is extracted from the leaves of the coca scrub (Erythroxylon coca) indigenous to the Andean highlands of South America. Colorectal: Related to the colon and/or rectum. Colorectal cancer: Cancer of the colon and rectum. A malignant tumor arising from the inner wall of the large intestine. Risk factors include heredity, colon polyps, and long standing ulcerative colitis. Most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer. Since colon polyps and early cancer can have no symptoms, regular screening is important. Diagnosis can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue. Surgery is the most common treatment for colorectal cancer. Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
Crabs: Slang for pubic lice. See: Public lice. Cure: 1. To heal, to make well, to restore to good health. Cures are easy to claim and, all too often, difficult to confirm. Cyanide: Poisoning with cyanide, a rapidly acting, potentially deadly chemical that can exist as a colorless gas, such as hydrogen cyanide (HCN) or cyanogen chloride (CNCl), or a crystal form such as sodium cyanide (NaCN) or potassium cyanide (KCN). Cyanide sometimes is described as having a "bitter almond" smell, but it does not always give off an odor, and not everyone can detect this odor. Cyanide is also known by the military designations AN (for hydrogen cyanide) and CK (for cyanogen chloride). Daily Value: DV, a term on food labels based on the RDA (Recommended Dietary Allowance) designed to help consumers use food label information to plan a healthy diet. Deletion: Loss of a segment of DNA from a chromosome (and hence from the genome). Department of Health and Human Services : The United States government's principal agency for "protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves." Also known as DHHS and HHS. Depression: An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression. Dermatology: 1. The branch of medicine concerned with the diagnosis, treatment, and prevention of diseases of the skin, hair, nails, oral cavity and genitals. 2. Sometimes also, cosmetic care and enhancement. 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). Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV. Diphtheria: An acute infectious disease that typically strikes the upper respiratory tract including the throat. It is caused by infection with the bacteria Corynebacterium diphtheriae. Symptoms include sore throat and mild fever at first. As the disease progresses, a membranous substance forms in the throat that makes it difficult to breathe and swallow. Disease surveillance: The ongoing systematic collection and analysis of data and the provision of information which leads to action being taken to prevent and control a disease, usually one of an infectious nature. Doxycycline: Brand name: Vibramycin. A synthetic broad-spectrum antibiotic derived from tetracycline. Doxycycline is used for many different types of infections, including respiratory tract infections due to Hemophilus influenzae, Streptococcus pneumoniae, or Mycoplasma pneumoniae. It is also used for the treatment of nongonococcal urethritis (due to Ureaplasma), Rocky Mountain spotted fever, typhus, chancroid, cholera, brucellosis, syphilis, and acne. 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. Encephalopathy: Disease, damage, or malfunction of the brain. In general, encephalopathy is manifested by an altered mental state that is sometimes accompanied by physical changes. Although numerous causes of encephalopathy are known, the majority of cases arise from infection, liver damage, anoxia, or kidney failure. The term encephalopathy is very broad and, in most cases, is preceded by various terms that describe the reason, cause, or special conditions of the patient that leads to brain malfunction. For example, anoxic encephalopathy means brain damage due to lack of oxygen, and hepatic encephalopathy means brain malfunction due to liver disease. Depending upon the cause and severity of the condition, symptoms may range from mild alterations in mental status to severe and potentially fatal manifestations such as dementia, seizures, and coma.
Environmental Protection Agency: The US government agency founded to "protect human health and to safeguard the natural environment--air, water, and land--upon which life depends." The Environmental Protection Agency is known as the EPA. Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction. Ephedra: A medicinal herb, known scientifically as Ephedra sinica and Ephedra equisetina, also known as mahuang and herbal ecstasy. Ephedra comes from the dried rhizome and root of the plant. Essential: 1. Something that cannot be done without. Essential oil: An oil derived from a natural substance, usually either for its healing properties or as a perfume. Some pharmaceuticals, and many over-the-counter or "holistic" remedies, are based on or contain essential oils. Examples include products containing camphor or eucalyptus that help relieve congestive coughs, and the essential oils used in the practice of aromatherapy. Expiration date: The date for a drug estimated for its shelf life with proper storage in sealed containers away from harmful and variable factors like heat and humidity. Father: (1) The male parent. (2) One who originates. For example, "Wilhelm Roentgen is considered the father of radiology." (3) To produce offspring as a male. (4) To provide paternal protection and guidance to children. Fats: Plural of the word "fat". See the definition of fat. Fatty acid: One of many molecules that are long chains of lipid-carboxylic acid found in fats and oils and in cell membranes as a component of phospholipids and glycolipids. (Carboxylic acid is an organic acid containing the functional group -COOH.) Fatty acids: Molecules that are long chains of lipid-carboxylic acid found in fats and oils and in cell membranes as a component of phospholipids and glycolipids. (Carboxylic acid is an organic acid containing the functional group -COOH.) FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. Fiber: The parts of plants that cannot be digested, namely complex carbohydrates. Also known as bulk or roughage. Focal: Pertaining to a focus which in medicine may refer to: Folate: Folic acid, one of the B vitamins that is a key factor in the synthesis (the making) of nucleic acid (DNA and RNA). Folic acid: One of the B vitamins that is a key factor in the synthesis (the making) of nucleic acid (DNA and RNA). Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. Food poisoning: A common flu-like illness typically characterized by nausea, vomiting and diarrhea, due to something the victim ate or drank that contained noxious bacteria, viruses, parasites, metals or toxins. Food security: When people do not need to live with hunger or fear starvation. Formulary: 1. A collection of formulas, recipes, or prescriptions. 2. In medicine, a listing of prescription drugs approved for use. Gastroenterology: The medical specialty devoted to the study, diagnosis and treatment of disorders of the digestive system. These disorders may affect the esophagus (swallowing tube), stomach, small intestine, large intestine (colon), rectum, liver, gallbladder, or pancreas. Gene: The basic biological unit of heredity. A segment of deoxyribonucleic acid (DNA) needed to contribute to a function. Generic: 1. The chemical name of a drug. 2. A term referring to the chemical makeup of a drug rather than to the advertised brand name under which the drug may be sold. 3.A term referring to any drug marketed under its chemical name without advertising. Generic drug: The term "generic" has several meanings as regards drugs:
See the entire definition of Generic drug Genes: The basic biological units of heredity. Segments of deoxyribonucleic acid (DNA) needed to contribute to a function. Genetic: Having to do with genes and genetic information. Gland: 1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland. Glucose: The simple sugar (monosaccharide) that serves as the chief source of energy in the body. Glucose is the principal sugar the body makes. The body makes glucose from proteins, fats and, in largest part, carbohydrates. Glucose is carried to each cell through the bloodstream. Cells, however, cannot use glucose without the help of insulin. Glucose is also known as dextrose. Health and Human Services : The United States government's principal agency for "protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves." Also known as DHHS and HHS. Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest. Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; Heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.
Heart valves: There are four heart valves. All are one-way valves. Blood entering the heart first passes through the tricuspid valve and then the pulmonary valve. After returning from the lungs, the blood passes through the mitral (bicuspid) valve and exits via the aortic valve. Hematology: The diagnosis, treatment, and prevention of diseases of the blood and bone marrow as well as of the immunologic, hemostatic (blood clotting) and vascular systems. Because of the nature of blood, the science of hematology profoundly affects the understanding of many diseases. Herbal: 1. An adjective, referring to herbs, as in an herbal tea. HHS: Acronym for the U.S. Department of Health and Human Services. Also known as DHHS. High blood pressure: Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. HIV: Acronym for the Human Immunodeficiency Virus, the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism). Homeopathic: Pertaining to homeopathy. House staff: The resident physicians of a hospital who care for patients under the direction of the attending staff. House in this context refers to the hospital. Human immunodeficiency virus: HIV, the cause of AIDS. HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism). Although the American research Robert Gallo at the National Institutes of Health believed he was the first to find HIV, it is now generally accepted that the French physician Luc Montagnier (1932-) and his team at the Pasteur Institute discovered HIV in 1983- 84. Hygiene: The science of preventive medicine and the preservation of health. From the name of Hygeia, the daughter of Asklepios, the Greek god of medicine (whose staff with entwined snake is the symbol of medicine). Asklepios (known to the Romans as Aesculapius) had a number of children including not only Hygeia but also Panaceia, the patroness of clinical medicine. Hygeia also followed her father into medicine. As the patroness of health, Hygeia was charged with providing a healthy environment to prevent illness. In Greek, "hygieia" means health. Hypertension: High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. Ibuprofen: A non-steroidal anti-inflammatory drug (NSAID) commonly used to treat pain, swelling, and fever. Common brand names for Ibuprofen include Advil, Motrin, and Nuprin. Immune: Protected against infection. The Latin immunis means free, exempt. Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders. Immunodeficiency: Inability to mount a normal immune response. Immunodeficiency can be due to a genetic disease or acquired as in AIDS due to HIV.
Implant: 1. To embed; to set in firmly. In embryology, the fertilized egg implants in the uterine lining 6 or 7 days after conception (fertilization). In medicine today, many things may be implanted. In vitro: Literally in glass, as in a test tube. A test that is performed in vitro is one that is done in glass or plastic vessels in the laboratory. Incidence: The frequency with which something, such as a disease, appears in a particular population or area. In disease epidemiology, the incidence is the number of newly diagnosed cases during a specific time period. The incidence is distinct from the prevalence which refers to the number of cases alive on a certain date. Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated. Infant: A child up to 2 years (24 months) of age. Infant formula: A substitute for breast milk for feeding infants. Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person. Informed consent: A process in which a person learns key facts about a clinical trial, including potential risks and benefits, before deciding whether or not to participate in a study. Informed consent continues throughout the trial. Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma. Insecticidal: Capable of killing insects or controlling their growth. Insecticide: A chemical used specifically to kill or control the growth of insects. Certain insecticides have been banned because of their adverse effects on animals or humans. Dursban (chlorpyrifos) is one that has been banned. Dursban causes weakness, vomiting, diarrhea and other ill effects in children. Dursban was in hundreds of products including some of Raid sprays, Hartz yard and kennel flea spray, and Black Flag liquid roach and ant killer. Insertion: Chromosome abnormality due to insertion of a segment from one chromosome into another chromosome. Institute of Medicine: One of the National Academies of the United States. The Institute of Medicine conducts policy studies on health issues. Institutional Review Board: IRB. A group of scientists, doctors, clergy, and consumers at each health care facility that participates in a clinical trial. IRBs are designed to protect study participants. They review and must approve the action plan for every clinical trial. They check to see that the trial is well designed, does not involve undue risks, and includes safeguards for patients. Iodide: The chemical form to which iodine in the diet is reduced before it is absorbed through the intestinal wall into the bloodstream and carried through the blood to the thyroid gland.
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. Isoflavone: A type of plant estrogen (phytoestrogen) found chiefly in soybeans. Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint. Labor: Childbirth, the aptly-named experience of delivering the baby and placenta from the uterus to the vagina to the outside world. There are two stages of labor. During the first stage (called the stage of dilatation), the cervix dilates fully to a diameter of about 10 cm. In the second stage (called the stage of expulsion), the baby moves out through the cervix and vagina to be born. Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems." 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. Lateral: 1. In anatomy, the side of the body or a body part that is farther from the middle or center of the body. Typically, lateral refers to the outer side of the body part, but it is also used to refer to the side of a body part. For example, when referring to the knee, lateral refers to the side of the knee farthest from the opposite knee. The opposite of lateral is medial. Laxative: Something that loosens the bowels. Used to combat constipation (and sometimes overused, producing diarrhea). The word "laxative" comes from the Latin "laxare" meaning "to open, widen, extend, release." Lens: The transparent structure inside the eye that focuses light rays onto the retina (the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain). The lens was named after the lentil bean because it resembled it in shape and size. Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body's tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues. MDMA: Abbreviation for 3-4 methylenedioxymethamphetamine. See: Ecstasy. Medical device: 1. Broadly, any physical item used in medical treatment, from a cardiac pacemaker to a wheelchair. Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed. Medical journals: In 1665 the Royal Society in England published one of the first 2 scientific journals in the world: the "Philosophical Transactions of the Royal Society." The other was the "Journal des Scavants" (Scholars) which appeared in France the same year. From these 2 journals are descended the many thousands of scientific periodicals today, including all those devoted to the biomedical sciences and medicine, whether they be in print or newer media such as on CD or the Internet. Mental retardation: A term used when a person has certain limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child. Children with mental retardation may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn. As many as 3 out of every 100 people have mental retardation. In fact, 1 out of every 10 children who need special education has some form of mental retardation. Metabolic: Relating to metabolism, the whole range of biochemical processes that occur within us (or any living organism). Metabolism consists of anabolism (the buildup of substances) and catabolism (the breakdown of substances). Metabolism: The whole range of biochemical processes that occur within an organism. Metabolism consists both of anabolism and catabolism (the buildup and breakdown of substances, respectively). The biochemical reactions are known as metabolic pathways and involve enzymes that transform one substance into another substance, either breaking down a substance or building a new chemical substance. The term is commonly used to refer specifically to the breakdown of food and its transformation into energy. Microbe: A very tiny form of life -- microbes include bacteria, fungi, and protozoan parasites -- best visualized under a microscope. Monoclonal: Pertaining to a single clone of cells, a single cell and the progeny of that cell. As opposed to polyclonal. Morphine: A powerful narcotic agent with strong analgesic (painkilling) action and other significant effects on the central nervous system. It is dangerously addicting. Morphine is a naturally occurring member of a large chemical class of compounds called alkaloids. Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral. MPH: Master of Public Health (a master's degree in this field of medicine). Naproxen: A non-steroidal anti-inflammatory drug (NSAID) used for the management of mild to moderate pain, fever, and inflammation. Naproxen blocks the enzyme cyclooxygenase that makes prostaglandins, resulting in lower concentrations of prostaglandins. As a consequence, inflammation, pain and fever are reduced. Brand names for naproxen include Anaprox, Naprelan, Naprosyn, and Aleve. National Academy of Sciences: One of the National Academies. Created in 1863 by a congressional charter approved by President Abraham Lincoln at the height of the Civil War. National Formulary: Full name: United States Pharmacopeia and National Formulary (USP-NF). An official publication, issued first by the American Pharmaceutical Association and now yearly by the United States Pharmacopeial Convention, that gives the composition, description, method of preparation, and dosage for drugs. The book contains two separate official compendia -- the USP and the NF. Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system. Neural: Having to do with nerve cells. Neurological: Having to do with the nerves or the nervous system. Nicotine: An alkaloid (a nitrogen-containing chemical) made by the tobacco plant or produced synthetically. In the plant kingdom, nicotine is not restricted to tobacco but is widespread. The tobacco plant, Nicotiana tabacum, belongs to the nightshade family, which also includes potatoes, tomatoes, eggplant and red peppers. All contain nicotine. However, the concentration of nicotine in those vegetables is far lower than the level in tobacco. Nicotine has powerful pharmacologic effects (including increased heart rate, heart stroke volume, and oxygen consumption by the heart muscle) as well as powerful psychodynamic effects (such as euphoria, increased alertness, and a sense of relaxation). As is now well known, nicotine is also powerfully addictive. When someone becomes habituated to nicotine and then stops using it, they experience the symptoms of withdrawal, including anxiety, irritability, restlessness, shortened attention span and an intense, sometimes irresistible, craving for nicotine. NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers. Noncompliance: The failure or refusal to comply: the failure or refusal to conform and adapt one's actions to a rule or to necessity. Nose: The external midline projection from the face. Nursing: 1) Profession concerned with the provision of services essential to the maintenance and restoration of health by attending the needs of sick persons. 2) Feeding a infant at the breast. Nutrition: 1) The science or practice of taking in and utilizing foods. 2) A nourishing substance, such as nutritional solutions delivered to hospitalized patients via an IV or IG tube. Obesity: The state of being well above one's normal weight. Offspring: The offspring are strictly speaking the progeny, or young, born to a person. Omega-3 fatty acids: A class of fatty acids found in fish oils, especially from salmon and other cold-water fish, that acts to lower the levels of cholesterol and LDL (low-density lipoproteins) in the blood. (LDL cholesterol is the "bad" cholesterol.) Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure. Ophthalmic: Pertaining to the eye. An ophthalmic ointment is designed for the eye. Opium: An addictive narcotic drug derived from the unripe seedpods of the opium poppy. Preparations of opium were called laudanum. Derivatives of laudanum include paregoric (a drug to treat diarrhea), morphine and heroin. Organic: 1. A chemical compound that contains carbon. Orphan drug: A drug designed to treat or prevent an orphan disease. Osteoarthritis: A type of arthritis caused by inflammation, breakdown, and eventual loss of cartilage in the joints. Also known as degenerative arthritis. Osteoporosis: Thinning of the bones with reduction in bone mass due to depletion of calcium and bone protein. Osteoporosis predisposes a person to fractures, which are often slow to heal and heal poorly. It is more common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes in posture, physical abnormality (particularly the form of hunched back known colloquially as "dowager's hump"), and decreased mobility. Outpatient: A patient who is not an inpatient (not hospitalized) but instead is cared for elsewhere -- as in a doctor's office, clinic, or day surgery center. The term outpatient dates back at least to 1715. Outpatient care today is also called ambulatory care.
OxyContin: A prescription painkiller that has become a popular and dangerous recreational drug. Also called "Oxy" in the street. Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors. Parasitic: Having to do with a parasite, as in a parasitic infection; or acting like a parasite by taking nourishment from another. Pediatric: Pertaining to children. Pediatrics: "Pediatrics is concerned with the health of infants, children and adolescents, their growth and development, and their opportunity to achieve full potential as adults." (Richard E.Behrman in Nelson's Textbook of Pediatrics) Pesticide: A chemical used to control, repel, or destroy pests of any sort. There are scores of different types of pesticides which may act specifically, for example, as acaricides (against mites), fungicides, herbicides, insecticides, molluscacides (against snails and other mollusks), pediculicides (against lice), rodenticides (against rats and other rodents), scabicides (against scabies), etc. Pharmacogenomics: The study of how variations in the human genome affect the response to medications. The older term "pharmacogenetics" was created from the words "pharmacology" and "genetics" to indicate the intersection of pharmaceuticals and genetics. The sequencing of the human genome and the introduction of new technologies have made it possible to analyze multiple genes simultaneously, rather than one at a time. The newer term "pharmacogenomics" describes such large-scale, often genomewide approaches. Pharmacopoeia: An official authoritative listing of drugs. Aspirin has, for example, long been in the pharmacopoeia. Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist. Phenylalanine: An essential amino acid. (The human body cannot make it so it is essential to the diet.) Phenylalanine that is ingested is largely transformed (hydroxylated) to form the amino acid tyrosine, which is used in protein synthesis. Too little phenylalanine curbs physical and intellectual growth. Too much phenylalanine, as in phenylketonuria (PKU), is highly toxic to the brain. Phenylanine was first isolated in 1879 and first synthesized in 1882. Symbol: Phe. Photodynamic therapy: A form of cancer treatment using an photosensitizing agent administered intravenously which concentrates selectively in tumor cells, followed by exposure of the tumor tissue to a special red laser light, in order to destroy as much of the tumor as possible. Placebo: A "sugar pill" or any dummy medication or treatment. Plasma: The liquid part of the blood and lymphatic fluid, which makes up about half of its volume. Plasma is devoid of cells and, unlike serum, has not clotted. Blood plasma contains antibodies and other proteins. It is taken from donors and made into medications for a variety of blood-related conditions. Some blood plasma is also used in non-medical products. Poisoning: Taking a substance that is injurious to health or can cause death. Poisoning is still a major hazard to children, despite child-resistant (and sometimes adult-resistant) packaging and dose-limits per container. Potassium: The major positive ion (cation) found inside of cells. The chemical notation for potassium is K+. Precursor: Forerunner. That which precedes or is derived from an available source. Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long. Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container. Prescription drug: A drug requiring a prescription, as opposed to an over-the-counter drug, which can be purchased without one. The word "prescription" comes from the Latin "praescriptus" compounded from "prae", before + scribere, to write = to write before. Historically, a prescription was written before the drug was prepared and administered. Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. Public health: The approach to medicine that is concerned with the health of the community as a whole. Public health is community health. It has been said that: "Health care is vital to all of us some of the time, but public health is vital to all of us all of the time." Qualified health claim: A claim authorized by the US Food and Drug Administration (FDA) that must be supported by credible scientific evidence regarding a relationship between a substance (specific food or food component) and a disease or health-related condition. Both of these elements -- a substance and a disease -- must be present in a health claim, An example of an authorized health claim is: "Calcium may reduce the risk of osteoporosis." Radiation: 1. Rays of energy. Gamma rays and X-rays are two of the types of energy waves often used in medicine. 2. The use of energy waves to diagnose or treat disease. See also: Irradiation. Radioactive: Emitting energy waves due to decaying atomic nuclei. Radioactive substances are used in medicine as tracers for diagnosis, and in treatment to kill cancerous cells. Radiology: The branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease. RDA: Abbreviation for the Recommended Dietary Allowance. Or, popularly, the Recommended Daily Allowance. Reagent: A substance used to produce a chemical reaction to detect, measure, produce, etc. other substances. Recommended Daily Allowance: Popular name for the Recommended Dietary Allowance (RDA). Rejection: In transplantation biology, the refusal by the body to accept transplanted cells, tissues or organs. For example, a kidney transplanted may be rejected.
Resistance: Opposition to something, or the ability to withstand it. For example, some forms of staphylococcus are resistant to treatment with antibiotics. Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again. Saccharin: An artificial sweetener which diluted in water is 300-500 times sweeter than the sugar sucrose. (The chemical name for saccharin is o-sulfabenzamide; 2,3-dihydro-3-oxobenzisosulfonazole). SAMHSA: The Substance Abuse and Mental Health Services Administration, a part of the U.S. Public Health Service, that works to improve the quality and availability of substance abuse prevention, addiction treatment, and mental health services. Provides funding through block grants to states for direct substance abuse and mental health services, including treatment for over 340,000 Americans with serious substance abuse problems. Helps improve substance abuse treatment through its Knowledge Development and Applications grant program. Monitors prevalence and incidence of substance abuse and mental illness. Established: 1992. (A predecessor agency, the Alcohol, Drug Abuse and Mental Health Administration, was established in 1974.) Headquarters: Rockville, MD. Saturated fat: A fat that is solid at room temperature and comes chiefly from animal food products. Some examples are butter, lard, meat fat, solid shortening, palm oil, and coconut oil. These fats tend to raise the level of cholesterol in the blood. Sclerosis: Localized hardening of skin. Seizure: Uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms. Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma. Serving size: 1. The portion of food used as a reference on the nutrition label of that food. Smallpox: Also known as variola, a highly contagious and frequently fatal viral disease characterized by a biphasic fever and a distinctive skin rash that left pock marks in its wake. Because of its high case-fatality rates and transmissibility, smallpox now represents a serious bioterrorist threat. The disease is caused by the variola virus. The incubation period is about 12 days (range: 7 to 17 days) following exposure. Initial symptoms include high fever, fatigue, and head and back aches. A characteristic rash, most prominent on the face, arms, and legs, follows in 2-3 days. The rash starts with flat red lesions that evolve at the same rate. Lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about 3-4 weeks. Smallpox vaccine: A vaccine containing a live virus called vaccinia used to prevent smallpox. The vaccine does not contain the variola virus that causes smallpox. Through the use of the vaccine, smallpox was eliminated from the world in 1977. Routine vaccination against smallpox ended in 1972 The level of immunity among persons who were vaccinated before 1972 is uncertain. In people exposed to smallpox who are not immune to the disease, the vaccine can lessen the severity of or even prevent the illness if given within 4 days of exposure. Sodium: The major positive ion (cation) in fluid outside of cells. The chemical notation for sodium is Na+. When combined with chloride, the resulting substance is table salt. Spongiform: Resembling a sponge in being soft and full of cavities, as in as in transmissible spongiform encephalopathy. Stroke: The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA. Substance: 1. Material with particular features, as a pressor substance.
Substance abuse: The excessive use of a substance, especially alcohol or a drug. (There is no universally accepted definition of substance abuse.) Substance Abuse and Mental Health Services Administration: A part of the U.S. Public Health Service, SAMHSA works to improve the quality and availability of substance abuse prevention, addiction treatment, and mental health services. Provides funding through block grants to states for direct substance abuse and mental health services, including treatment for over 340,000 Americans with serious substance abuse problems. Helps improve substance abuse treatment through its Knowledge Development and Applications grant program. Monitors prevalence and incidence of substance abuse and mental illness. Established: 1992. (A predecessor agency, the Alcohol, Drug Abuse and Mental Health Administration, was established in 1974.) Headquarters: Rockville, MD. Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc. Surgeon General: In the United States, the chief medical officer of the U.S. Public Health Service (USPS), the agency responsible for the public health of the American people. The Public Health Service (PHS) administers a number of critically important health agencies including the Food and Drug Administration (FDA), the Centers for Disease Control (CDC), and the National Institutes of Health (NIH). Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease. Temple: An area just behind and to the side of the forehead and the eye, above the side of the check bone (the zygomatic arch) and in front of the ear. Tetanus: An often fatal infectious disease caused by the bacteria Clostridium tetani (C. tetani) which usually enters the body through a puncture, cut, or open wound. Tetanus is characterized by profoundly painful spasms of muscles, including "locking" of the jaw so that the mouth cannot open (lockjaw). C. tetani releases a toxin that affects the motor nerves, (the nerves which stimulate the muscles). Thallium: A metallic element having the symbol Tl and the atomic number 81 and an atomic weight of about 204. Therapeutic: Relating to therapeutics, that part of medicine concerned specifically with the treatment of disease. The therapeutic dose of a drug is the amount needed to treat a disease. Therapeutics: In medicine, the branch that deals specifically with the treatment of disease and the art and science of healing. Therapy: The treatment of disease. Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus. Thyroid: 1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.) Thyroid gland: A gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. Thyroid hormones also help children grow and develop. Tobacco: A South American herb, formally known as Nicotiana tabacum, whose leaves contain 2-8% nicotine and serve as the source of smoking and smokeless tobacco. Tooth: The structures within the mouth that allow for biting and chewing. Teeth have different shapes, depending on their purpose. The sharp canine and frontal teeth allow for biting, while the flattened, thick molars in the back of the mouth provide grinding surfaces for masticating food. All teeth have essentially the same structure: a hard crown above the gum line, which is attached to two or four roots by a portion called the neck. The roots are covered with a very thin layer of bone, and keep the tooth embedded in the bones of the jaw. The exposed exterior of the tooth is covered with tough enamel. Under the enamel is a thick layer of dentin, and in the center is the pulp. Blood vessels and nerves are found within the pulp. Toxicity: The degree to which a substance can harm humans or animals. Toxicology: The study of the nature, effects and detection of poisons and the treatment of poisoning. Toxin: One of a number of poisons produced by certain plants, animals, and bacteria. Transfusion: The transfer of blood or blood products from one person (the donor) into another person (the recipient's) bloodstream. In most situations, this is done as a lifesaving maneuver to replace blood cells or blood products lost through severe bleeding. Transfusion of your own blood (autologous) is the safest method but requires planning ahead and not all patients are eligible. Directed donor blood allows the patient to receive blood from known donors. Volunteer donor blood is usually most readily available and, when properly tested has a low incidence of adverse events. Tuberculosis: A highly contagious infection caused by the bacterium called Mycobacterium tuberculosis. Abbreviated TB. Tubercles (tiny lumps) are a characteristic finding in TB. Diagnosis may be made by skin test, which if positive should will be followed by a chest X-ray to determine the status (active or dormant) of the infection. Tuberculosis is more common in people with immune system problems, such as AIDS, than in the general population. Treatment of active tuberculosis is mandatory by law in the US, and should be available at no cost to the patient through the public health system. It involves a course of antibiotics and vitamins that lasts about six months. It is important to finish the entire treatment, both to prevent reoccurrence and to prevent the development of antibiotic-resistant tuberculosis. Most patients with tuberculosis do not need to be quarantined, but it is sometimes necessary. Tylenol: See: Acetaminophen. Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy. US Department of Agriculture: A department of the executive branch of the US government founded in 1862 by President Abraham Lincoln -- he called it the "people's Department" -- that is devoted to agriculture in its broadest sense. USDA: US Department of Agriculture. Vaccines: Microbial preparations of killed or modified microorganisms that can stimulate an immune response in the body to prevent future infection with similar microorganisms. These preparations are usually delivered by injection. Vascular: Relating to the blood vessels of the body. The blood vessels of the body, as a group, are referred to as the vascular system. Veterinary medicine: The medical science concerned with the diagnosis, treatment and prevention of diseases in animals. Aside from diagnosing and treating sick and injured animals, veterinarians prevent the transmission of animal diseases to people, and advise owners on the proper care of animals. Veterinarians work to ensure a safe food supply by maintaining the health of agricultural animals and by inspecting food processing industries. Veterinarians are also involved in the preservation of wildlife. Veterinary school is usually 4 years and requires a prior college degree in the US and Canada. The degree is a DMV (Doctor of Veterinary Medicine). Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash." Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult. Viruses: Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected. Vitamin A: Vitamin A is retinol. Carotene compounds (found, for example, in egg yolk, butter and cream) are gradually converted by the body to vitamin A (retinol). A form of vitamin A called retinal is responsible for transmitting light sensation in the retina of the eye. Vitamin B12: A vitamin important for the normal formation of red blood cells and the health of the nerve tissues. Undetected and untreated vitamin B12 deficiency can lead to anemia and permanent nerve and brain damage. Vitamin B6: A group of closely related chemical compounds with related names -- pyridoxine, pyridoxal and pyridoxamine -- that are transformed within the body to yet another form of vitamin B6, pyridoxal phosphate, that acts as a coenzyme. (A number of vitamins serve as coenzymes, substances that enhance the action of enzymes and thereby aid in catalyzing biochemical reactions.) Vitamin C: An essential nutrient found mainly in fruits and vegetables. The body requires vitamin C to form and maintain bones, blood vessels, and skin. Vitamin E: Alpha-tocopherol, an antioxidant vitamin which binds oxygen free radicals that can cause tissue damage. Deficiency of vitamin E can lead to anemia. Vitamin E may play a possible role in preventing heart disease and cancer of the lung and prostate. Vitamins: The word "vitamin" was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance "vitamine" because he believed it was necessary to life and it was a chemical amine. The "e" at the end was later removed when it was recognized that vitamins need not be amines. Voluntary: Done in accordance with the conscious will of the individual. The opposite of involuntary. Watson: See: Watson, James. Yogurt: A common dish made of milk curdled and fermented with a culture of Lactobacillus (the milk bacillus). The word was acquired in the 1620s from Turkey. It can be spelled myriad ways including yogurt, yoghurt, yaghourt, yooghurt, yughard, and yaourt. The most popular spellings in the Anglo-Saxon world are yogurt and yoghurt while in France one eats yaourt.
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