Glossary of Medical Terms


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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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.

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.

Abdominal pain

Pain in the belly. Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity, the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity. These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.

Abnormal

Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer).

Absorption

Uptake. In the biomedical sciences, absorption has diverse specific meanings.

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.

Analysis

A psychology term for processes used to gain understanding of complex emotional or behavioral issues.

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.

Anesthesia

Loss of feeling or awareness. A general anesthetic puts the person to sleep. A local anesthetic causes loss of feeling in a part of the body such as a tooth or an area of skin without affecting consciousness. Regional anesthesia numbs a larger part of the body such as a leg or arm, also without affecting consciousness. The term "conduction anesthesia" encompasses both local and regional anesthetic techniques. Many surgical procedures can be done with conduction anesthesia without significant pain. In many situations, such as a C-section, conduction anesthesia is safer and therefore preferable to general anesthesia. However, there are also many types of surgery in which general anesthesia is clearly appropriate.

Ankle

The ankle joint is complex. It is made up of two joints: the true ankle joint and the subtalar joint.

Antidepressants

Anything, and especially a drug, used to prevent or treat depression.

Antihistamines

Drugs that combat the histamine released during an allergic reaction by blocking the action of the histamine on the tissue. Antihistamines do not stop the formation of histamine nor do they stop the conflict between the IgE and antigen. Therefore, antihistamines do not stop the allergic reaction but protect tissues from some of its effects. Antihistamines frequently cause mouth dryness and sleepiness. Newer "non sedating" antihistamines are generally thought to be somewhat less effective. Antihistamine side effects that very occasionally occur include urine retention in males and fast heart rate.

Apnea

An apnea is a period of time during which breathing stops or is markedly reduced. There are two types of apneas, the more common obstructive sleep apnea and the less common central sleep apnea.

Artery

A vessel that carries blood high in oxygen content away from the heart to the farthest reaches of the body. Since blood in arteries is usually full of oxygen, the hemoglobin in the red blood cells is oxygenated. The resultant form of hemoglobin is what makes arterial blood look bright red.

Arthritis

Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain.

Aspartame

A man-made sweetener with almost no calories used in place of sugar.

Asthma

A common disorder in which chronic inflammation of the bronchial tubes makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs or the lung tissue itself.

Atherosclerosis

A process of progressive thickening and hardening of the walls of medium-sized and large arteries as a result of fat deposits on their inner lining.

Bariatric

Pertaining to bariatrics, the field of medicine concerned with weight loss

Bariatric surgery

Surgery on the stomach and/or intestines to help a person with extreme obesity lose weight. Bariatric surgery is an option for people who have a body mass index above 40. Surgery is also an option for people with a BMI between 35 and 40 who have health problems like type 2 diabetes or heart disease.

Baseline

1. Information gathered at the beginning of a study from which variations found in the study are measured. 2. A known value or quantity with which an unknown is compared when measured or assessed. 3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.

Belly

That part of the body that contains all of the structures between the chest and the pelvis. Also called the abdomen.

Bioelectric impedance analysis

A seemingly simple method for determining the lean body mass. Abbreviated BIA. There are two methods of the BIA. One involves standing on a special scale with footpads. A harmless amount of electrical current is sent through the body, and then the percentage of body fat is calculated. The other type of BIA involves electrodes usually placed on a wrist and an ankle and on the back of the right hand and on the top of the foot. The change in voltage between electrodes is measured. The person's body fat percentage is then calculated from the results of the BIA.

Blood clots

Blood that has been converted from a liquid to a solid state. Also called a thrombus.

Blood glucose

The main sugar that the body makes from the food in the diet. Glucose is carried through the bloodstream to provide energy to all cells in the body. Cells cannot use glucose without the help of insulin.

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 is measured after the heart contracts and is highest. The second 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".

Blood sugar

Blood glucose.

BMI

Body mass index.

BOD POD

A method for determining the lean body mass. The BOD POD is a computerized, egg-shaped chamber. Using the same whole-body measurement principle as underwater weighing, the BOD POD measures a subject's mass and volume, from which their whole-body density is determined. Using these data, body fat and lean muscle mass can then be calculated.

Body mass index

A key index for relating a person's body weight to their height. The body mass index is a person's weight in kilograms divided by their height in meters squared.

Bone density

Bone density is the amount of bone tissue in a certain volume of bone. It can be measured using a special x-ray called a quantitative computed tomogram.

Bowel

Another name for the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively.

Brain

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

Breast cancer

Breast cancer is diagnosed with self- and physician-examination of the breasts, mammography, ultrasound testing, and biopsy. There are many types of breast cancer that differ in their capability of spreading to other body tissues. Treatment of breast cancer depends on the type and location of the breast cancer, as well as the age and health of the patient. The American Cancer Society recommends that a woman should have a baseline mammogram between the ages of 35 and 40 years. Between 40 and 50 years of age mammograms are recommended every other year. After age 50 years, yearly mammograms are recommended.

Bypass

An operation in which a surgeon creates a new tubular pathway for the movement of fluids and/or other substances in the body.

Caffeine

A stimulant found naturally in coffee beans, tea leaves, cocoa beans and kola nuts 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.

Calipers

A metal or plastic tool similar to a compass used to measure the diameter of an object. The skin fold thickness in several parts of the body can be measured with skin calipers to determine the lean body mass. This may be done in medicine, physical anthropology, health clubs, and athletic facilities.

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.

Carbohydrates

Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources by the body. Carbohydrates can also be defined chemically as neutral compounds of carbon, hydrogen and oxygen.

Cerebrovascular

Pertaining to the blood vessels and, especially, the arteries that supply the brain. As in cerebrovascular accident or cerebrovascular disease.

Cerebrovascular accident

The sudden death of some brain cells due to lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A CVA is also referred to as a stroke.

Chest

The area of the body located between the neck and the abdomen. The chest contains the lungs, the heart and part of the aorta. The walls of the chest are supported by the dorsal vertebrae, the ribs, and the sternum

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.

Chronic

This important term in medicine comes from the Greek chronos, time and means lasting a long time.

Chronic disease

A disease that persists for a long time. A chronic disease is one lasting 3 months or more, by the definition of the U.S. National Center for Health Statistics. Chronic diseases generally cannot be prevented by vaccines or cured by medication, nor do they just disappear. Eighty-eight percent of Americans over 65 years of age have at least one chronic health condition. Health damaging behaviors - particularly tobacco use, lack of physical activity, and poor eating habits - are major contributors to the leading chronic diseases.

Clinical trials

Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people.

Colon

The part of the large intestine that runs from the cecum to the rectum as a long hollow tube that serves to remove water from digested food and let the remaining material, solid waste called stool, move through it to the rectum and leave the body through the anus.

Congestive heart failure

Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath , asthma due to the heart , pooling of blood in the general body circulation or in the liver's circulation, swelling, blueness or duskiness, and enlargement of the heart.

Coronary artery disease

A major cause of illness and death, coronary artery disease begins when hard cholesterol substances are deposited within a coronary artery.

Deep vein thrombosis

A blood clot in a deep vein in the thigh or leg. The clot can break off as an embolus and make its way to the lung, where it can cause respiratory distress and respiratory failure.

Degenerative arthritis

Also known as osteoarthritis, this type of arthritis is caused by inflammation, breakdown and eventual loss of the cartilage of the joints. Among the over 100 different types of arthritis conditions, osteoarthritis is the most common, affecting usually the hands, feet, spine, and large weight-bearing joints, such as the hips and knees. Also called degenerative joint disease.

Dehydration

Excessive loss of body water. Diseases of the gastrointestinal tract that cause vomiting or diarrhea may, for example, lead to dehydration. There are a number of other causes of dehydration including heat exposure, prolonged vigorous exercise, kidney disease, and medications.

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.

DEXA

Dual energy X-ray absorptometry.

Dexfenfluramine

A weight loss drug, in a class of drugs called anorectics which decrease appetite. This drug, sold in the US under the brand name Redux, was withdrawn from the US market in 1997, and has since been withdrawn worldwide and is no longer available because of its association with abnormal heart valve findings, primarily aortic regurgitation.

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.

Diarrhea

A familiar phenomenon with unusually frequent or unusually liquid bowel movements, excessive watery evacuations of fecal material. The opposite of constipation. The word "diarrhea" with its odd spelling is a near steal from the Greek "diarrhoia" meaning "a flowing through." Plato and Aristotle may have had diarrhoia while today we have diarrhea. There are myriad infectious and noninfectious causes of diarrhea.

Discharge

1.The flow of fluid from part of the body, such as from the nose or vagina. 2. The passing of an action potential, such as through a nerve or muscle fiber. 3. The release of a patient from a course of care. The doctor may then dictate a discharge summary.

Dopamine

An important neurotransmitter in the brain.

Embolism

The obstruction of a blood vessel by a foreign substance or a blood clot blocking the vessel. Something travels through the bloodstream, lodges in a vessel and plugs it.

Enzymes

Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.

Epidemic

The occurrence of more cases of a disease than would be expected in a community or region during a given time period. A sudden severe outbreak of a disease such as SARS. From the Greek "epi-", "upon" + "demos", "people or population" = "epidemos" = "upon the population." See also: Endemic; Pandemic.

Esophagus

The tube that connects the pharynx with the stomach. The esophagus lies between the trachea and the spine. It passes down the neck, pierces the diaphragm just to the left of the midline, and joins the cardiac end of the stomach. In an adult, the esophagus is about 25 centimeters long. When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Glands in the lining of the esophagus produce mucus, which keeps the passageway moist and facilitates swallowing. Also known as the gullet or swallowing tube. From the Greek oisophagos, from oisein meaning to bear or carry + phagein, to eat.

Essential

1. Something that cannot be done without. 2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid. 3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."

Estrogen

Estrogen is a female hormone produced by the ovaries. Estrogen deficiency can lead to osteoporosis.

Fatigue

A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.

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.

Fenfluramine

A weight loss drug, in a class of drugs called anorectics which decrease appetite. This drug, sold in the US under the brand name Pondimin, was withdrawn from the US market in 1997, and has since been withdrawn worldwide and is no longer available because of its association with abnormal heart valve findings, primarily aortic

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.

Forceps

An instrument with two blades and a handle used for handling, grasping, or compressing. Many types of forceps are employed in medicine, including the alligator forceps, tissue forceps, hemostatic forceps, mosquito forceps and obstetrical forceps.

Fructose

A sugar that occurs naturally in fruits and honey. Fructose has 4 calories per gram.

Gallbladder

A pear-shaped organ just below the liver that stores the bile secreted by the liver. During a fatty meal, the gallbladder contracts, delivering the bile through the bile ducts into the intestines to help with digestion. Abnormal composition of bile leads to formation of gallstones, a process termed cholelithiasis. The gallstones cause cholecystitis, inflammation of the gallbladder.

Gallstones

Stones that form when substances in the bile harden. Gallstones can be as small as a grain of sand or as large as a golf ball. There can be just one large stone, hundreds of tiny stones, or any combination.

Gastric

Having to do with the stomach.

Gastric banding

A surgically implanted device used to help a person lose weight. In a surgical procedure, a band is placed around the upper part of the stomach, creating a small pouch that can hold only a small amount of food. The narrowed opening between the stomach pouch and the rest of the stomach controls how quickly food passes from the pouch to the lower part of the stomach. The system helps the patient eat less by limiting the amount of food that can be eaten at one time and increasing the time it takes for food to be digested.

Gastrointestinal

Adjective referring collectively to the stomach and small and large intestines.

Gastrointestinal tract

The tube that extends from the mouth to the anus in which the movement of muscles and release of hormones and enzymes digest food. The gastrointestinal tract starts with the mouth and proceeds to the esophagus, stomach, duodenum, small intestine, large intestine, rectum and, finally, the anus. Also called the alimentary canal, digestive tract and, perhaps most often in conversation, the GI tract.

Genetic

Having to do with genes and genetic information.

Genetic disease

A disease caused by an abnormality in an individual's genome.

Genetics

The scientific study of heredity. Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc.

Glucose

The simple sugar 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.

Gout

Condition characterized by abnormally elevated levels of uric acid in the blood, recurring attacks of joint inflammation, deposits of hard lumps of uric acid in and around the joints, and decreased kidney function and kidney stones. Uric acid is a breakdown product of purines, that are part of many foods we eat. The tendency to develop gout and elevated blood uric acid level is often inherited and can be promoted by obesity, weight gain, alcohol intake, high blood pressure, abnormal kidney function, and drugs. The most reliable diagnostic test for gout is the identification of crystals in joints, body fluids and tissues.

HDL

High density lipoprotein

HDL cholesterol

Lipoproteins, which are combinations of lipids and proteins, are the form in which lipids are transported in the blood. The high-density lipoproteins transport cholesterol from the tissues of the body to the liver so it can be gotten rid of. HDL cholesterol is therefore considered the "good" cholesterol. The higher the HDL cholesterol level, the lower the risk of coronary artery disease.

Headache

A pain in the head with the pain being above the eyes or the ears, behind the head, or in the back of the upper neck. Headache, like chest pain or back ache, has many causes.

Health for All

A global health movement undertaken by the World Health Organization in the late 20th century.

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 attack

The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.

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; Dilated cardiomyopathy; Heart attack; Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.

Heart failure

Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath, asthma due to the heart, pooling of blood in the general body circulation or in the liver's circulation, swelling, blueness or duskiness, and enlargement of the heart.

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 valve and exits via the aortic valve.

Herbal

1. An adjective, referring to herbs, as in an herbal tea. 2. A noun, usually reflecting the botanical or medicinal aspects of herbs; also a book which catalogs and illustrates herbs. The word "herbal" was pronounced with a silent "h" on both sides of the Atlantic until the 19th century but this usage persists only on the American side.

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.

Hormone

A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.

Hypercholesterolemia

High blood cholesterol. This can be sporadic or familial. Hypercholesterolemia is one form of hyperlipidemia.

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.

Hypothyroid

Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck.

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.

Infection

The growth of a parasitic organism within the body. A person with an infection has another organism growing within him, drawing its nourishment from the person.

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 with a wound or with trauma.

Insomnia

The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability. See the entire definition of Insomnia

Insulin

A natural hormone made by the pancreas that controls the level of the sugar glucose in the blood. Insulin permits cells to use glucose for energy. Cells cannot utilize glucose without insulin.

Insulin resistance

The diminished ability of cells to respond to the action of insulin in transporting glucose from the bloodstream into muscle and other tissues. Insulin resistance typically develops with obesity and heralds the onset of type 2 diabetes. It is as if insulin is "knocking" on the door of muscle. The muscle hears the knock, opens up, and lets glucose in. But with insulin resistance, the muscle cannot hear the knocking of the insulin. The pancreas makes more insulin, which increases insulin levels in the blood and causes a louder "knock." Eventually, the pancreas produces far more insulin than normal and the muscles continue to be resistant to the knock. As long as one can produce enough insulin to overcome this resistance, blood glucose levels remain normal. Once the pancreas is no longer able to keep up, blood glucose starts to rise, initially after meals, eventually even in the fasting state. Type 2 diabetes is now overt.

Iron

An essential mineral. Iron is necessary for the transport of oxygen and for oxidation by cells. Deficiency of iron is a common cause of anemia. Food sources of iron include meat, poultry, eggs, vegetables and cereals. 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 sometimes without knowing it and also in people receiving recurrent blood transfusions. Iron supplements meant for adults are a major cause of poisoning in children.

Large bowel

Another name for the large intestine.

Lean body mass

The mass of the body minus the fat. There are a number of methods for determining the lean body mass. Some of these methods require specialized equipment such as underwater weighing, BOD POD, and DEXA. Other methods for determining the lean body mass are simple such as skin calipers and bioelectric impedance analysis.

Leptin

A hormone that has a central role in fat metabolism. Leptin was originally thought to be a signal to lose weight but it may, instead, be a signal to the brain that there is fat on the body.

Lumen

A luminous term referring to the channel within a tube such as a blood vessel or to the cavity within a hollow organ such as the intestine. Lumen is a luminous term because it is Latin for light, including the light that comes through a window. When a hollow organ is cut across, you can see light through the space that has been opened. So the word "lumen" came to mean this space.

Lungs

The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Malnutrition

A term used to refer to any condition in which the body does not receive enough nutrients for proper function. Malnutrition may range from mild to severe and life-threatening. It can be a result of starvation, in which a person has an inadequate intake of calories, or it may be related to a deficiency of one particular nutrient. Malnutrition can also occur because a person can not properly digest or absorb nutrients from the food they consume, as may occur with certain medical conditions. Malnutrition remains a significant global problem, especially in developing countries.

Marker

A piece of DNA that lies on a chromosome so close to a gene that the marker and the gene are inherited together. A marker is thus an identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA or a segment of DNA with no known coding function. All that matters is that the marker can be detected and trailed.

Menopause

The time in a woman's life when menstrual periods permanently stop; it is also called the "change of life." Menopause is the opposite of the menarche.

Menstrual

Pertaining to menstruation, as in last menstrual period, menstrual cramps, menstrual cycle, and premenstrual syndrome. From the Latin menstrualis, from mensis meaning month.

Menstrual cycle

The monthly cycle of changes in the ovaries and the lining of the uterus, starting with the preparation of an egg for fertilization. When the follicle of the prepared egg in the ovary breaks, it is released for fertilization and ovulation occurs. Unless pregnancy occurs, the cycle ends with the shedding of part of the endometrium, which is menstruation. Although it is actually the end of the physical cycle, the first day of menstrual bleeding is designated as "day 1" of the menstrual cycle in medical parlance.

Metabolic

Relating to metabolism, the whole range of biochemical processes that occur within us. Metabolism consists of anabolism and catabolism.

Metabolism

The whole range of biochemical processes that occur within an organism. Metabolism consists both of anabolism and catabolism. 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.

Mortality

A fatal outcome or, in one word, death. The word "mortality" is derived from "mortal" which came from the Latin "mors". The opposite of mortality is, of course, immortality. Mortality is also quite distinct from morbidity.

Muscle

Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Muscular

Having to do with the muscles. Also, endowed with above average muscle development. Muscular system refers to all of the muscles of the body collectively.

Nerve

A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another.

Normal range

By convention, the normal range for whatever is set to cover ninety-five percent of all values from the general population. Five percent of results consequently fall outside the normal range. Values that prove normal can therefore sometimes be outside the normal range.

Nurses Health Study

A very large and important prospective investigation into the risk factors for major chronic diseases in women. The participants in the study are female registered nurses.

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.

Obese

Well above ones normal weight. A person has traditionally been considered to be obese if they are more than 20 percent over their ideal weight. That ideal weight must take into account the person's height, age, sex, and build.

Obesity

The state of being well above one's normal weight.

Onset

In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis. There is always an onset to a disease but never to the return to good health. The default setting is good health.

Organ

A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver.

Osteoarthritis

A type of arthritis caused by inflammation, breakdown, and eventual loss of cartilage in the joints. Also known as degenerative arthritis.

Osteoporosis

The female gonad, the ovary is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs and female hormones. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a fallopian tube to the uterus. The ovaries are the main source of female hormones, which control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.

Overweight

The term "overweight" is used in two different ways. In one sense it is a way of saying imprecisely that someone is heavy. The other sense of "overweight" is more precise and designates a state between normal weight and obesity.

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.

Pancreas

A fish-shaped spongy grayish-pink organ about 6 inches long that stretches across the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum. The narrow end of the pancreas, called the tail, extends to the left side of the body.

Phenylalanine

An essential amino acid. Phenylalanine that is ingested is largely transformed 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.

Phenylketonuria

The inherited inability to metabolize the essential amino acid phenylalanine due to complete or near-complete deficiency of the enzyme phenylalanine hydroxylase.

Placenta

A temporary organ joining the mother and fetus, the placenta transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste products from the fetus. It is roughly disk-shaped, and at full term measures about seven inches in diameter and a bit less than two inches thick. The upper surface of the placenta is smooth, while the under surface is rough. The placenta is rich in blood vessels.

Polycystic ovary syndrome

Abbreviated PCOS. Polcystic ovary syndrome is a condition in women characterized by irregular or no menstrual periods, acne, obesity, and excess hair growth. PCOS is a disorder of chronically abnormal ovarian function and hyperandrogenism. It affects 5-10% of women of reproductive age. PCOS is also called the Stein-Leventhal syndrome.

Postmenopausal

After the menopause. Postmenopausal is defined formally as the time after which a woman has experienced twelve consecutive months of amenorrhea without a period.

Potassium

The major positive ion found inside of cells. The chemical notation for potassium is K+.

Pound

A measure of weight equal to 16 ounces or, metrically, 453.6 grams. The word "pound" goes back to the Latin "pondo" which meant a "weight". The abbreviation for pound-just to confuse non-pound people-is lb. which stands for "libra".

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. It is conventionally divided into three trimesters, each roughly three months long.

Pregnant

The state of carrying a developing fetus within the body.

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; 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, giving the directions to be marked on the container.

Prevalence

The proportion of individuals in a population having a disease. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time.

Prospective

Looking forward. A prospective study or a prospective clinical trial is one in which the participants are identified and then followed forward in time.

Prospective study

A study in which the subjects are identified and then followed forward in time.

Prostate

A gland within the male reproductive system that is located just below the bladder. Chestnut shaped, the prostate surrounds the beginning of the urethra, the canal that empties the bladder.

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.

Pulmonary

Having to do with the lungs.

Pulmonary hypertension

High blood pressure in the pulmonary artery that conveys blood from the right ventricle to the lungs. The pressure in the pulmonary artery is normally low compared to that in the aorta. Pulmonary hypertension can irrevocably damage the lungs and cause failure of the right ventricle.

Rectum

The last 6 to 8 inches of the large intestine. The rectum stores solid waste until it leaves the body through the anus. The word rectum comes from the Latin rectus meaning straight.

Regimen

With the accent on the first syllable, a regimen is a plan, a regulated course such as a diet, exercise or treatment, designed to give a good result. A low-salt diet is a regimen.

Relapse

The return of signs and symptoms of a disease after a patient has enjoyed a remission. For example, after treatment a patient with cancer of the colon went into remission with no sign or symptom of the tumor, remained in remission for 4 years, but then suffered a relapse and had to be treated once again for colon cancer.

Resistance

Opposition to something, or the ability to withstand it. For example, some forms of staphylococcus are resistant to treatment with antibiotics.

Saccharin

An artificial sweetener which diluted in water is 300-500 times sweeter than the sugar sucrose.

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.

Sensation

In medicine and physiology, sensation refers to the registration of an incoming nerve impulse in that part of the brain called the sensorium, which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors.

Sensitivity

1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.

Serotonin

A hormone, also called 5-hydroxytryptamine, in the pineal gland, blood platelets, the digestive tract, and the brain. Serotonin acts both as a chemical messenger that transmits nerve signals between nerve cells and that causes blood vessels to narrow.

Shock

In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume and not enough output of blood by the heart. The signs and symptoms of shock include low blood pressure, overbreathing, a weak rapid pulse, cold clammy grayish-bluish skin, decreased urine flow, and mental changes.

Shortness of breath

Difficulty in breathing. Medically referred to as dyspnea. Shortness of breath can be caused by respiratory or circulatory conditions. See also dyspnea.

Skin calipers

A simple method for determining the lean body mass. This method involves measuring the skinfold thickness of the layer of fat just under the skin in several parts of the body with calipers. The results are then calculated and the percentage of body fat is determined. Skin calipers can yield inaccurate results if an inexperienced person uses them on someone with significant obesity.

Sleep

The body's rest cycle.

Sleep apnea

The temporary stoppage of breathing during sleep, often resulting in daytime sleepiness. Apnea is a Greek word that means "want of breath."

Small bowel

Another name for the small intestine.

Sodium

The major positive ion in fluid outside of cells. The chemical notation for sodium is Na+. When combined with chloride, the resulting substance is table salt.

Stomach

The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.

Stress

Forces from the outside world impinging on the individual. Stress is a normal part of life that can help us learn and grow. Conversely, stress can cause us significant problems.

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.

Surgery

The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England is a physician's or dentist's office.

Sympathetic nervous system

A part of the nervous system that serves to accelerate the heart rate, constrict blood vessels, and raise blood pressure. The sympathetic nervous system and the parasympathetic nervous system constitute the autonomic nervous system, the branch of the nervous system that performs involuntary functions.

Synapse

The point of connection usually between two nerve cells. Specifically, a synapse is a specialized junction at which a nerve cell communicates with a target cell. The neuron releases a chemical transmitter that diffuses across a small gap and activates specific specialized sites called receptors situated on the target cell. The target cell may be another neuron, or a specialized region of a muscle cell or a secretory cell. Neurons can also communicate through direct electrical connections.

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.

Systemic

Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.

Thrombosis

The formation or presence of a blood clot in a blood vessel. The vessel may be any vein or artery as, for example, in a deep vein thrombosis or a coronary thrombosis. The clot itself is termed a thrombus. If the clot breaks loose and travels through the bloodstream, it is a thromboembolism. Thrombosis, thrombus, and the prefix thrombo- all come from the Greek thrombos meaning a lump or clump, or a curd or clot of milk. See entries also to: Cavernous sinus thrombosis; Renal vein thrombosis.

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.

Transplant

The grafting of a tissue from one place to another, just as in botany a bud from one plant might be grafted onto the stem of another. The transplanting of tissue can be from one part of the patient to another, as in the case of a skin graft using the patient's own skin; or from one patient to another, as in the case of transplanting a donor kidney into a recipient.

Treadmill

A machine with a moving strip on which one walks without moving forward. A treadmill was originally a wide wheel turned by the weight of people climbing on steps around its edge, used in the past to provide power for machines or as a punishment in prisons.

Underwater weighing

A method for determining the lean body mass. This method weighs a person underwater and then calculates the lean body mass and body fat. This method is one of the more accurate ones. However, it is generally done in special research facilities, and the equipment is costly. Also called hydrostatic weighing.

Uterus

The uterus is a hollow, pear-shaped organ located in a woman's lower abdomen between the bladder and the rectum. The narrow, lower portion of the uterus is the cervix; the broader, upper part is the corpus. The corpus is made up of two layers of tissue.

Vein

A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system which returns blood to the heart.

Vitamins

The word "vitamin" was coined in 1911 by the Warsaw-born biochemist Casimir Funk. At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation 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.

Weight loss

Weight loss is a decrease in body weight resulting from either voluntary or involuntary circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption, and chronic inflammation.

World Health Organization

An agency of the United Nations established in 1948 to further international cooperation in improving health conditions. Although the World Health Organization inherited specific tasks relating to epidemic control, quarantine measures, and drug standardization from the Health Organization of the League of Nations and from the International Office of Public Health at Paris, the World Health Organization was given a broad mandate under its constitution to promote the attainment of "the highest possible level of health" by all people. WHO defines health positively as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity."

Wrist

The proximal segment (the near part) of the hand consisting of the carpal bones and the associated soft parts.

X-ray

1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances, of acting on a photographic film or plate, and of causing a fluorescent screen to give off light. In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer. Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.

Xylitol

A sweetener found in plants that is used as a substitute for sugar. Xylitol is considered a nutritive sweetener because it provides calories, just like sugar.

                                                                                                                                               
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