GLOSSARY OF MEDICAL TERMS

Abortion

The interruption of pregnancy through expulsion of the fetus before it can survive outside the uterus (generally before the 20th week of pregnancy). Abortion may be either induced (also called therapeutic) or spontaneous.

Abscess

A localized buildup of pus due to the breakdown of tissue by bacteria.

Acidosis

A disrupted acid/alkaline balance due to a depletion of the body's alkali supplies or a production of acid. The condition is linked with several disorders, such as diabetes.

Acne

The inflammation of the sebaceous (oil) glands due to a buildup of sebum, a fatty substance discharged through the pores to lubricate the skin. The condition is associated with the hormonal changes of adolescence, but may occur at any age.

Addiction

Physical and emotional dependence on a drug due to the body's adaptation to its presence.

See

Pernicious anemia.

Addison's disease

A disorder caused by insufficient secretion of aldosterone and cortisol from the adrenal glands, resulting in a variety of serious symptoms.

Adhesion

The abnormal union of body surfaces caused by fibrous scars formed when tissues heal.

Adolescence

The stage of development between puberty and full maturity.

Adrenal glands

Endocrine glands that are situated just above the kidneys and which secrete important hormones. Among the hormones secreted are epinephrine (adrenaline), which affects heart rate and blood circulation and is instrumental in the body's response to physical stress, and cortisone, a natural anti-inflammatory. See also Epinephrine, Cortisone.

See

Epinephrine.

Adrenocorticotropic hormone (ACTH)

A hormone produced by the pituitary gland in order to induce the secretion of corticoids from the adrenal glands.

Afterbirth

The collection of special tissues that are associated with fetal development and which are expelled after the delivery of the body. See also Placenta.

Agalactia

The inability to produce milk after childbirth.

AIDS (acquired immune deficiency syndrome)

An incurable disease that attacks and weakens the body's immune system, leaving the patient open to opportunistic infections and disorders that are normally warded off.

Albumin

A protein found in animals, plants, and egg whites; the presence of albumin in the urine could indicate kidney disease.

Alcoholism

Dependence on or addiction to alcohol. A poisoning of the body with alcohol. Physical damage can occur in the liver, heart, and kidneys as a result of alcohol poisoning. It can also lead to decreased resistance to infections.

Alkali

Opposite and neutralizer of acid. Bicarbonate is the body's chief alkali.

Allergen

Any agent that produces an allergic reaction. Common allergens include animal fur, pollen, dust, and certain foods. See also Allergy.

Allergy

A hypersensitive or exaggerated reaction to exposure to certain substances (see also Allergen) or conditions (such as sun rays). Manifestations of allergies include rashes, coldlike symptoms, headaches, gastrointestinal symptoms, and asthma.

Alveoli

The microscopic air sacs in the lungs through which oxygen and carbon dioxide are exchanged.

Amenorrhea

The failure to menstruate. Amenorrhea is a symptom of many diseases and conditions.

Amino acid

The nitrogen-containing components of protein used by the body to build muscle and other tissue. Some essential amino acids must be supplied by eating high-protein foods while others are synthesized in the body.

Amnesia

Memory loss.

Amniocentesis

The extraction and examination of a small amount of the amniotic fluid in order to determine genetic and other disorders in the fetus. See also Amniotic fluid.

Amnion

The bag of waters in which the fetus and the amniotic fluid are contained during pregnancy.

Amniotic fluid

The fluid surrounding the fetus.

Amphetamine

A drug that stimulates the central nervous system.

Analgesic

Any substance that gives temporary relief from pain.

Androgen

Hormones, such as testosterone and androsterone, that are produced in the testes and are responsible for male characteristics. They are also produced normally in small amounts in females.

Androsterone

One of the male sex hormones.

Anemia

A deficiency in the hemoglobin, the number of red blood cells, or in the amount of blood. Anemia is usually a symptom of an underlying disorder.

Anesthesia

Loss of sensation or feeling. General anesthesia involves the whole body while local anesthesia involves a particular area.

Anesthesiology

The branch of medicine dealing with anesthesia and the application of anesthetic agents in surgery and pain relief.

Aneurysm

A sac filled with blood that forms as a result of an abnormal widening of a vein or artery.

Angina

Intense pain that produces a feeling of suffocation. The term is commonly used to refer to chest pains (angina pectoris) that are usually a result of an interruption of the oxygen supply to the heart muscle.

Angiography

Examination of the interior blood vessels by injecting radiopaque substances so that any disorder or abnormality shows up on x-ray film. The record of pictures is called an angiogram.

Anoxia

Oxygen deficiency.

Antacid

An acid-neutralizing substance.

Antibiotic

An antibacterial substance derived from bacteria, molds, and other substances. Penicillin is a common antibiotic.

Antibody

The components of the immune system that eliminate or counteract foreign substances (antigens) in the body.

Anticoagulant

An agent that retards the blood-clotting process.

Antidote

An agent that counteracts the effects of a poison.

Antigen

A substance, usually a protein found in germs or foreign tissue, that stimulates the production of antibodies.

Antihistamine

A drug that blocks histamine action. Since histamines are often produced in large amounts in response to allergens, they cause many of the symptoms associated with allergies; antihistamines are often used to relieve allergic reactions, such as hay fever or hives. Antihistamines also may be prescribed to counter nausea.

Antihypertensive

Any drug that lowers blood pressure.

Antiseptic

Any substance that prevents or slows the proliferation of germs or bacteria.

Antitoxin

An antibody produced by or introduced into the body to counteract a poison.

Anus

The opening at the end of the rectum (the last segment of the large intestine) through which fecal waste passes.

Anvil

One of the tiny bones in the middle ear (also called the incus).

Anxiety

Feelings of apprehension and undue uneasiness. Appropriate anxiety may occur in the face of identifiable danger. In contrast, clinical anxiety is the feeling of apprehension or fear, even in the face of no identifiable hazards.

Aorta

The body's largest artery, it carries blood pumped from the left ventricle of the heart and distributes it to all parts of the body.

Aphasia

Loss of the ability to speak or to understand speech due to brain damage. The organs of speech may be unimpaired.

Apnea

The absence of breathing.

Appendicitis

An inflammation of the appendix that results in severe pain on the lower right side, fever, and nausea or vomiting. Appendicitis calls for immediate medical attention, usually requiring removal of the appendix.

Aqueous humor

The fluid in the anterior part of the eyeball.

Areola

A round pigmented area around a raised center, such as the nipple of a breast.

Arrhythmia

Any deviation from the regular heartbeat rhythm.

Arteriole

A tiny artery that joins another artery to the capillaries.

Arteriosclerosis

Also called hardening of the arteries, this condition involves a thickening of the arterial walls resulting in a loss of elasticity. See also Atherosclerosis.

Artery

A blood vessel that transports oxygenated blood away from the heart to the rest of the body.

Arthritis

Inflammation of a joint.

Ascorbic acid

Vitamin C.

Asphyxia

Suffocation due to lack of oxygen or overabundance of carbon dioxide.

Aspiration

The removal of fluids from the lungs or other body cavities. A suction or siphoning implement is used.

Aspirin

Acetylsalicylic acid. A drug used to relieve pain and lower fever. It is also an anti-inflammatory drug and anticoagulant.

Asthma

A disorder of the respiratory system due to bronchial spasm that results in breathing difficulties.

Astigmatism

A defect in one of the eye's surfaces that leads to an inability to focus the eye correctly.

Atherosclerosis

A form of arteriosclerosis in which, in addition to the thickening and reduced elasticity of the arteries, a fatty substance (plaque) forms on the inner walls of the arteries, causing obstruction of blood flow.

See

Tinea pedia.

Atrophy

Wasting; degeneration of a body part through lack of activity or nourishment.

Auscultation

A method of examining the body by listening, usually using a stethoscope.

Autoimmune disease

Any disease in which the body manufactures antibodies against itself. The body regards its own tissue as a foreign body and acts accordingly to eliminate it.

Bacilli

Rod-shaped bacteria.

Bacteria

One-celled microscopic organisms. Some cause disease, others are harmless, and some are beneficial.

See

Amnion.

Barbiturate

A drug that produces sedation, hypnosis, anesthesia, or sleep.

Barium tests

Diagnostic tests using barium, a metallic element that does not permit x-rays to pass through and therefore makes internal organs visible on x-ray films. Common barium tests are the barium swallow (upper GI series) and the barium enema (lower GI series).

B cell

A specialized type of white cell (lymphocyte) that works as part of the immune system by providing antibodies that attack foreign agents such as bacteria or viruses.

Bedsore

Decubitus ulcer; an ulcerlike sore on the skin as a result of the pressure of the bed against the body.

Bell's palsy

A paralysis of the face muscles due to the inflammation of the facial nerve.

Benign

Harmless or innocent. Term is used to describe a nonmalignant tumor that will not spread or grow back after removal.

Bile

The bitter alkaline fluid secreted by the liver to aid in digestion. Bile is greenish yellow until it is stored in the gallbladder, where it becomes darker.

Biofeedback

A behavior modification therapy by which a patient is taught to control involuntary body functions such as blood pressure.

Biopsy

The examination of a small sample of tissue taken from a patient's body, usually used to determine if a growth is cancerous.

See

Contraception.

Birthmark

A colored patch or skin blemish that is present at birth.

Blackhead

An open comedo, in which a follicle is clogged by fatty substances secreted by the sebaceous glands. Its black coloration is caused by exposure to air, not dirt as is commonly assumed.

Bladder

A sac that contains fluid or gas.

See

Cystitis.

Blastomycosis

A fungal disease usually affecting the lungs but sometimes the whole system.

Blind spot

The spot where the optic nerve and the retina connect. It is not light sensitive.

Blister

An accumulation of fluid causing a raised sac under the surface of the skin.

Blood

The body fluid circulated by the heart through a network of arteries, veins, and capillaries to provide oxygen and nutrients to all body cells and to remove carbon dioxide and wastes from them.

Blood clotting

The process of blood coagulation in which blood platelets and proteins join together to close up a break in the circulatory system.

Blood corpuscle

Either a red blood cell (erythrocyte) or a white blood cell (leukocyte).

Blood count

The amount of red and white blood cells in the blood.

Blood plasma

The part of the blood that is composed mostly of water (over 90 percent). The other constituents include electrolytes, nutrients, wastes, clotting agents, antibodies, and hormones.

Blood pressure

The force exerted by the blood against the arterial walls. A sphygmomanometer measures both the systolic pressure (when the heart is at maximum contraction) and diastolic pressure (when the heart is relaxed between beats).

Blood serum

The liquid that separates from the blood when it clots. It is the plasma without the clotting agents and is yellowish in color.

Blood sugar

The glucose that is circulated in the blood. It is the end product of carbohydrate metabolism (although protein and some fat also may be converted to glucose) and is the body's major fuel.

Blood transfusion

The intravenous replacement or replenishment of a patient's blood with healthy, compatible blood from an outside source.

Blood type

Grouping of hereditary factors in the blood. The four major groupings are O, A, B, and AB. It is essential to determine if the donor's and recipient's blood types are compatible before a transfusion is administered.

Blood vessel

A vein or artery.

Boil

A round, painful, pus-filled bacterial infection of a hair follicle, usually caused by staphylococci (also called furuncle).

Bone graft

Transplantation of bone from one person to another or from one part of the body to another.

Boric acid

A mild antiseptic powder that is poisonous if swallowed. It was once considered a useful household first-aid item, but it is no longer recommended because of its limited effectiveness and potential toxicity.

Botulism

A dangerous form of food poisoning caused by the toxin produced by botulinus bacteria. The toxin attacks the nervous system causing headache, weakness, constipation, and paralysis. The causative bacterium grows in anaerobic (without oxygen) conditions and therefore is found in improperly canned or improperly refrigerated fresh foods.

Bowel

Intestine, gut.

Brain

The central organ of the nervous system consisting of the cerebrum, cerebellum, pons varolii, midbrain, and medulla.

Breast

The mammary (milk-producing) gland and the fat and connective tissue around it.

Breech delivery (or presentation)

Delivery of a baby with either the feet or buttocks instead of the head emerging first.

Bright's disease

A term formerly used to describe nephrosis, a disease affecting the kidney's filtering units (nephrons).

Bromides

A group of drugs once used as anticonvulsants because of their sedative effects on the central nervous system. They have been replaced by newer, more effective drugs that do not have as high a risk of adverse reactions.

Bronchi

The two tubes branching off at the lower part of the trachea (singular: bronchus).

Bronchiole

Subdivision of a bronchus that leads to the alveoli in the lungs.

Bronchitis

Inflammation of the bronchi.

Bronchopneumonia

Bacterial infection that results in the inflammation of the bronchioles.

Bruise

Damage to the subcutaneous blood vessels resulting in the escape of blood into the other tissues. Characteristic features are pain, swelling, and discoloration of the skin. A bruise in which the outer layer of skin is not broken is called a contusion. An abrasion or laceration is a bruise in which the skin is broken.

Bulimia

Excessive appetite. Also refers to the binge/purge syndrome, in which deliberate overeating is compensated for through self-induced vomiting, laxative use, excessive exercise, or starvation.

Bunion

A deformity of the big toe resulting from an inflammation of the joint that connects the toe to the foot.

Bursa

A fibrous, fluid-filled sac in the joints that aids movement by decreasing friction.

Bursitis

A painful condition involving inflammation of the bursa, a fluid-filled sac in a joint.

Caffeine

A substance that stimulates the central nervous system. It is present in coffee, tea, chocolate, and certain soft drinks.

Calamine lotion

A compound containing zinc oxide used to treat skin rashes, irritations, and other skin disorders.

Calcium

An essential mineral. Calcium is the main material in teeth and bones and vital to proper function of the heart, other muscles, and other body tissues.

Calculus

Abnormal stone formation in certain parts of the body such as the gallbladder or kidneys. Calculi are composed of minerals, cholesterol, bile pigments, or other substances, depending upon their location (plural: calculi).

Callus

1. An area where the skin has become thick in order to protect itself against repeated friction. 2. The partly calcified tissue that forms around a broken bone in the healing process.

Calorie

Measure of energy (heat) used in physics and in nutrition.

Cancer

A general term referring to the abnormal reproduction of cells in the body. The term covers more than 100 different malignant tumors and conditions.

Candidiasis

A yeast infection caused by the Candida fungus. Also called moniliasis or thrush.

Canker sore

An ulcerlike sore on the mucous membrane of the mouth or lips.

Capillary

Minute thin-walled blood vessel, in a network that facilitates the exchange of substances be-tween the surrounding tissues and the blood.

Carbohydrates

Organic compounds of carbon, hydrogen, and oxygen. They include starches, cellulose, and sugars and are divided into three groups: monosaccharides (simple sugars), disaccharides (containing two different sugars), and polysaccharides (complex sugars).

Carcinogen

Any agent that is capable of causing cancer.

Carcinoma

The type of cancer that originates in the epithelial cells located in glands, skin, and mucous membranes.

Cardiac

Pertaining to the heart.

Cardiograph

A device for tracing the movements of the heart. The record produced is called a cardiogram or electrocardiogram.

Cardiopulmonary

Pertaining to the heart and lungs.

Cardiovascular

Pertaining to the heart and blood vessels.

Carditis

Inflammation of the heart.

Caries

Tooth or bone decay.

Cartilage

The white, elastic tissue located in joints, the nose, and the outer ear.

Cast

Fibrous material that has collected in body cavities and hardens to the shape of them.

Castor oil

An oil derived from a poisonous bean plant and that acts as a purgative or cathartic.

Castration

The removal of ovaries or testes.

Cataract

An opacity or clouding of the eye lens, which can eventually lead to loss of vision as progressively less light is filtered through the lens to the retina.

Cathartic

Any substance that stimulates rapid intestinal activity resulting in bowel evacuation (also called purgative).

Catheterization

Any procedure in which a small flexible tube is inserted into the body for the purpose of withdrawing or introducing substances.

Caustic

Having the ability to destroy or corrode organic tissue.

Cauterization

The application of caustic chemicals or electrically heated devices for the purpose of eliminating infected, unwanted, or dead tissue.

Cavities

1. Extension of dental decay through enamel. 2. Hollow spaces.

Cell

A minute mass of protoplasm containing a nucleus; the structural unit of body tissue.

Cellulose

A polysaccharide carbohydrate (starch) found in plant cells. It is indigestible by humans but aids in the overall digestive process by providing roughage.

Cerebellum

The movement-coordinating part of the brain.

Cerebral cortex

The convoluted outer surface of the brain.

Cerebrum

The largest part of the brain, containing two hemispheres and the cerebral cortex, which controls thinking, feeling, and voluntary activities.

Cervix

The neck; also the narrow part of the uterus.

Cesarean section

Delivery of a baby through the abdominal wall by means of a surgical procedure.

Chancre

The highly infectious ulcerated sore that is the first sign of syphilis.

Chemotherapy

The use of chemicals to treat disease with minimal damage to the patient. Use in the treatment of cancer is widespread and has increased life expectancy of patients.

Chilblains

Painful and itchy swelling of skin due to exposure to the cold.

Cholera

An epidemic disease characterized by diarrhea, vomiting, thirst, and cramps. It is spread through polluted water.

Cholesterol

A crystalline fatlike substance found in all animal cells. It is synthesized in the liver and is essential in the production of sex hormones, nerve function, and a number of other vital processes. Excessive consumption of dietary cholesterol (found only in animal products) is thought to contribute to heart disease.

Chorea

A disease of the nervous system manifested by spasmodic movements of the body.

Chromosome

Any one of the rod-shaped bodies in the nucleus of a cell that carry hereditary factors.

Cirrhosis

Chronic inflammation and hardening of an organ, usually the liver, but occasionally the heart or kidneys are involved.

Cleft palate

Congenital defect of the mouth in which the palate bones fail to fuse and result in a groove in the roof of the mouth. Harelip is often associated with cleft palate.

Climacteric

Menopause.

Clitoris

A small organ situated at the front of the vulva that is one source of the female orgasm. It contains erectile tissue and is the female counterpart of the male penis.

Colic

Spasmodic pain in the abdomen.

Colitis

Inflammation of the colon (large intestine), characterized by bowel spasms, diarrhea, and constipation. Ulcerative colitis is a more serious form of the disease, and is characterized by open sores in the lining of the colon and the passage of diarrhea streaked with blood and mucus.

Colon

Large intestine extending from the small intestine to the rectum. Undigested food that is not absorbed by the body passes from the small intestine into the colon; water is extracted from the waste and it is eventually eliminated from the body in the form of a bowel movement.

Colostomy

Surgical procedure to create an artificial anus in the abdominal wall.

Colostrum

The pale yellow "first milk" secreted by women in the late stages of pregnancy and just after delivery.

Colposcope

A magnifying device used to examine the cervix and vagina.

Coma

State of unconsciousness from which one cannot be awakened.

Communicable disease

Transmissible to other persons.

Conception

Impregnation of the ovum by the sperm.

Concussion

Injury resulting from a severe blow or shock to the head.

Congenital

Existing at birth or before.

Congestive heart failure

A condition in which the heart is unable to pump strongly enough to maintain normal blood circulation. As a result, blood backs up in the lungs and veins leading to the heart. Often accompanied by accumulation of fluid in various parts of the body.

Conjunctiva

The transparent membrane lining the front of the eyeball and eyelid.

Conjunctivitis

Inflammation of the conjunctiva.

Constipation

A condition of infrequent and difficult bowel movements.

Contraception

Prevention of conception; birth control.

Contraceptive

An agent used in preventing conception.

Contusion

A bruise; bleeding under the skin.

Convulsions

Involuntary spasms due to abnormal cerebral stimulation.

Cornea

The transparent membrane that protects the outer surface of the eye.

Corn

A patch of thickened skin (callus) usually occurring around the toes and caused by friction or pressure.

Coronary

Related to the coronary arteries, the blood vessels that supply the heart muscle with blood.

Coronary artery disease

Progressive narrowing of the coronary arteries, usually due to a buildup of fatty plaques (atheromas) along the vessel walls. The most common cause of angina pectoris and heart attacks. See also Heart attack.

Coronary thrombosis

The blockage of a coronary artery with a clot (thrombus), a common cause of heart attacks.

Corpuscle

A small mass of protoplasm. Red corpuscles are called erythrocytes and white corpuscles are called leukocytes.

Cortisol

A principal hormone produced by the adrenal gland.

Cortisone

Hormone preparation closely related to cortisol that acts as an anti-inflammatory agent and is used in treating various diseases; corticosteroid.

Coryza

Acute upper respiratory infection lasting only a short while; head cold.

Cowpox

A viral disease of cattle used to vaccinate against smallpox in humans. Since the worldwide elimination of smallpox, vaccination against this disease is no longer necessary.

Cranium

The section of the skull that encases the brain.

Curettage

A scraping out of tissue from an organ (particularly the uterus) for diagnostic purposes with a forklike instrument called a curet.

Cuspid

Canine tooth; tooth having only one point.

Cuticle

The epidermis (outer layer of skin); dead skin, especially that which surrounds fingernails and toenails.

Cyanosis

A condition in which tissue takes on a bluish tinge due to lack of oxygen.

Cyst

An abnormal cavity or sac enclosing a fluid, gas, or semisolid substance.

Cystic fibrosis

A hereditary respiratory disease occurring in early childhood. It is characterized by the buildup of mucus in the lungs and other abnormalities affecting the exocrine system (glands that secrete directly into their target organs, such as the sweat glands).

Cystitis

Infection and inflammation of the urinary bladder.

Cystoscopy

A diagnostic procedure involving examination of the bladder with a cystoscope inserted through the urethra.

Cytology

The study of the origins, structures, and functions of cells.

Dandruff

A common condition in which white scales and flakes of dead skin appear on the scalp.

Debility

Lessened ability; weakness.

Decubitus ulcer

Bedsore.

Defibrillation

Cessation of fibrillation (tremor or twitching of cardiac muscle) and resumption of normal heart rate through electric shock (defibrillator) or drugs.

Deficiency disease

Disorder resulting from a nutritionally deprived diet or inability of the body to absorb needed nutrients.

Degenerative disease

A group of diseases characterized by deterioration of body part(s) and resulting in progressive disability.

Dehydration

Inadequate amount of fluids in the body caused by re-moval, abnormal loss, or failure to ingest fluids.

Delirium

Mental disorder characterized by delusions or hallucinations. May be caused by disease, high fever, or drug use.

Delirium tremens

Delirium suffered by chronic alcoholics as a result of withdrawal. Characterized by vivid hallucinations, uncontrollable trembling of hands, confusion, and nausea.

Delusion

A false belief that persists even in the presentation of contrary evidence.

Dementia

Deterioration of mental faculties due to irreversible organic causes.

Dementia praecox

Schizophrenia.

Dendrite

One of the threadlike branches of the nerve cell that transmits an impulse to the cell body.

Dentin

The calcified tissue that encloses the tooth's pulp cavity.

Deoxyribonucleic acid (DNA)

The fundamental component of all living matter that controls and transmits the hereditary genetic code.

Depilatory

An agent that removes hair.

Depressant

An agent that produces a calming, sedative effect, slowing down body functions.

Depression

An organic disease characterized by profound feelings of sadness, discouragement, and worth-lessness unexplained by life's events. Depression is often recurring and interrupted by feelings of extreme euphoria, a condition referred to as bipolar depression or manic-depressive state.

Derma or dermis

The skin.

Dermatitis

Inflammation of the skin.

Desensitization (immunotherapy)

Neutralization of allergies by periodic exposure to progressively larger doses of the allergen.

Dextrose

A form of glucose, a simple sugar.

Diabetes mellitus

A chronic condition characterized by an overabundance of blood sugar due to insufficient insulin production in the pancreas or inability of the body to utilize insulin.

Dialysis

A technique for separation of waste products or toxins from the bloodstream. Used in cases of kidney failure and overdose.

Diaphragm

1. The large muscle between the chest and the abdomen. 2. A dome-shaped rubber cap inserted vaginally to cover the cervix in order to prevent conception.

Diastole

The interval between contractions of the heart (heartbeat) in which the heart relaxes. The diastolic reading obtained in blood pressure measurement is the lower number.

Diethylstilbestrol (DES)

Synthetic estrogen hormone once used to prevent miscarriage. Its use is believed to have resulted in a higher incidence of vaginal and reproductive abnormalities, including difficulty in achieving or maintaining a pregnancy, among daughters born to women who took it. Sons may also suffer reproductive abnormalities. DES is also used to prevent conception if given promptly after unprotected intercourse (the so-called morning-after pill). Since it causes severe nausea and vomiting and other adverse effects, its use is limited primarily to rape victims.

Digestion

The process by which food is transformed into absorbable nutrients.

Digit

Finger or toe.

Dilation

Enlargement or expansion of an organ, a passageway (e.g., blood vessel or the pupil of the eye). May be artificially induced for therapeutic or diagnostic purposes.

Diplopia

Double vision.

Disk (vertebral)

The cartilage cushions between the vertebrae.

Dislocation

The displacement of a bone from its normal position in a joint.

Diuretic

Any substance that increases the flow of urine and excretion of body fluid.

Diverticula

Pouchlike sacs protruding from the wall of an organ.

Diverticulitis

Inflammation of diverticula.

Diverticulosis

A disorder in which diverticula develop. Most commonly seen in the intestinal tract.

Dominant

A term used in genetics to describe the stronger of two hereditary traits.

Dorsal

Pertaining to the back.

Down syndrome

A congenital condition that may include mental retardation and physical malformations caused by abnormal chromosomal distribution. Also called trisomy 21. Formerly called mongolism.

See

Edema.

Duodenum

The portion of the small intestine closest to the stomach.

Dura mater

The outermost layer of fibrous membrane covering the brain and spinal cord. One of three types of meninges.

Dysentery

Infectious inflammation of the bowel characterized by diarrhea with passage of blood and mucus and severe abdominal cramps.

Dyslexia

Learning disability characterized by impaired reading ability and tendency to reverse characters.

Dysmenorrhea

Painful menstruation or cramps.

Dyspareunia

Painful sexual intercourse.

Dyspepsia

Indigestion.

Dysphagia

Difficulty in swallowing.

Dyspnea

Difficulty in breathing.

Dystrophy

Wasting, usually due to defective metabolism or nutrition.

Dysuria

Painful urination.

Echography

The use of ultrasound waves in detecting and diagnosing abnormalities. The results are called an echogram.

Eclampsia

A sudden convulsive attack caused by toxemia during pregnancy.

Ectopic pregnancy

Pregnancy in which the fertilized egg begins to develop outside the uterus, usually in the fallopian tubes.

Eczema

Skin rash characterized by itching and scaling.

Edema

Swelling of body tissue caused by a buildup of fluid.

Effusion

An accumulation of fluid between body tissues or in body cavities.

Ejaculation

Emission of semen from the penis during the male orgasm.

Electrocardiography

A diagnostic procedure in which metal plates (electrodes) are placed on body surfaces for the purpose of detecting and tracing electrical impulses from the heart. The resulting graph is called an electrocardiogram (EKG or ECG).

Electroencephalography

A diagnostic procedure in which the electrical impulses from the brain are traced and recorded through metal plates (electrodes) attached to the head. The resulting graph is called an electroencephalogram (EEG).

Electrolysis

Decomposition or destruction by means of electricity.

Electroshock therapy (EST)

The use of a controlled amount of electric current in treatment of severe depression. The electric shock is administered through electrodes placed on the head.

Embolism

Obstruction of a blood vessel by a solid body, called an embolus. Common emboli include blood clots, fat globules, or air bubbles.

Embryo

The term used to refer to the fetus in the first 8 weeks after conception.

Emetic

Agent that induces vomiting.

Emission

Discharge of fluid.

Emphysema

A respiratory disease characterized by progressive loss of elasticity of lung tissue, making it difficult to exhale stale air fully. Most commonly caused by smoking.

Empyema

Accumulation of pus in a body cavity, usually the lungs.

Encephalitis

Inflammation of the brain due to virus infection, lead poisoning, or other causes.

Endocrine system

The physiological network of ductless glands that secrete hormones into the bloodstream to control the digestive and reproductive systems, growth, metabolism, and other processes.

Endometriosis

A gynecological disease in which tissue normally found in the uterus grows in other areas.

Endometrium

The lining of the uterus in which the fertilized ovum is implanted and which is shed during menstruation if conception has not taken place.

Endoscopy

Diagnostic procedure using an illuminating optical instrument to examine a body cavity or internal organ.

Enema

Fluid injected through the rectum to the lower bowel. Used to induce bowel movement or diagnose bowel disorders (barium enema).

Enteritis

Inflammation of the intestine.

Enuresis

Inability to control urination while sleeping; bed-wetting.

Enzyme

A substance, usually protein, that causes a chemical reaction; a catalyst.

Epidermis

Outermost layer of skin.

Epiglottis

The flap of cartilage that covers the larynx in the act of swallowing and aids in directing food to the esophagus.

Epilepsy

A disease of the nervous system characterized by convulsive seizures as a result of an imbalance in the electrical activity of the brain.

Epinephrine (also called adrenaline)

The hormone produced by the medulla (inner core) of the adrenal glands. It is secreted in stressful situations in order to increase the body's capacity to respond or to speed up bodily processes.

Episiotomy

An incision made in the final stages of childbirth from the vagina downward toward the anus.

Erection

The stiffening or swelling of the penis or other erectile tissue as it becomes filled with blood.

Erysipelas

A severe infectious skin disease caused by a streptococcal organism and characterized by swelling and redness.

Erythema

Reddening of the skin due to dilation of the capillaries under the skin.

Erythroblastosis fetalis

The anemic condition in infants due to Rh incompatibility between mother and child. The condition is seen in Rh-positive babies born to Rh-negative women.

Erythrocyte

Red blood corpuscle.

Esophagus

Tube that transports food from the mouth to the stomach.

Estrogen

A primarily female sex hormone produced by the ovary, adrenal gland, and placenta. In women, it controls development of secondary sex characteristics, menstruation, and pregnancy. A small amount of estrogen is produced in the testes of the man, and also in fat tissue.

Eustachian tube

The tube that connects the middle ear to the pharynx.

Exophthalmos

Protruding eyeballs, sometimes due to diseases of the thyroid gland.

Expectorant

A drug that promotes the coughing of sputum.

Faint

Brief loss of consciousness due to insufficient blood in the brain.

Fallopian tubes

The two tubes extending one from each side of the uterus through which an egg must pass after release from the ovary. Also called oviducts.

Farsightedness

Also called hyperopia. A disorder of the eyes that causes difficulty in focusing on an object close up.

Fascia

Thin connective tissues that join the skin to underlying tissues.

Fat

An essential nutrient of animal or plant origin. May be saturated or unsaturated.

Fauces

The opening from the throat to the pharynx.

Feces

The waste matter discharged from the bowels.

Femur

Thigh bone.

Fertility

The ability to conceive.

Fertilization

Impregnation of ovum by sperm cell.

Fetus

An unborn baby after the eighth week of pregnancy.

Fever

Abnormally high body temperature. Generally above 98.6oF or 37oC.

Fiber

1. Body tissue composed mainly of fibrils, tiny threadlike structures. 2. The plant cell components that are indigestible by humans; dietary fiber; roughage.

Fibrillation

Uncoordinated tremors or twitching of cardiac muscle resulting in an irregular pulse.

Fibrin

Protein formed in blood during clotting process.

Fibroid

A benign tumor of fibromuscular tissue, usually occurring in the uterus.

Fibula

The long, thin bone found in the lower leg.

Fission

Splitting.

Fistula

An abnormal connection between two body cavities.

Flat foot

A congenital or acquired deformity in which there is only a slight, or no, arch between the toes and the heel of the foot.

Flatulence

An overabundance of gas in the stomach or intestines.

Fluorine

A chemical that in small amounts prevents tooth decay.

Fluoroscope

A special x-ray that projects images on a screen. Used to observe the organs or bones while in motion.

Folic acid

A B-complex vitamin, used to promote blood regeneration in cases of folate deficiency. Occurs naturally in liver, kidney, green vegetables, and yeast.

Follicle

A small sac or tubular gland.

Fontanel

A membranous spot on a baby's head where skull bones have not yet come together.

Foramen

An opening. Usually used in reference to the opening in a bone through which blood vessels or nerves pass.

Forceps

Surgical instrument used to grasp or compress tissues.

Fracture

A crack or break in a bone.

Frontal

Pertaining to the front of a structure.

Frostbite

Freezing of the skin as a result of exposure to extreme cold. Affected area may become red and inflamed.

Fulminating

Developing quickly and with great severity.

Fungicide

Any substance that eliminates fungi.

Fungus

A low form of vegetable life in-cluding some that can cause disease. Fungal infections.

Furuncle (boil)

A round, painful, pus-filled bacterial infection of a hair follicle.

Gallbladder

A membranous sac that is situated below the liver and condenses and stores the bile drained from the liver.

Gallstones

Stonelike masses that form in the gallbladder. May be composed of calcium, bile pigment, and/or cholesterol.

Gamma globulin

The type of blood protein that contains antibodies to fight infection. Gamma globulin can be separated from the other constituents in the blood and used to prevent or treat infections.

Ganglion

1. A mass of nerve tissue, a nerve center. 2. A cystic tumor in a tendon sheath.

Gangrene

Death of body tissue usually due to loss of blood supply. Af-fected area becomes shrunken and black.

Gastrectomy

Surgical removal of a part or all of the stomach.

Gastric

Pertaining to the stomach.

Gastric juice

Acidic secretion of the stomach containing enzymes and hydrochloric acid to aid in digestion.

Gastric ulcer

A peptic ulcer that forms in the stomach.

Gastritis

Inflammation of the stomach.

Gastroenteritis

Inflammation of the mucous membranes of the stomach and intestines.

Gastroenterology

Study of the stomach and intestines and the diseases affecting them.

Gastrostomy

Surgically formed fistula between the stomach and abdominal wall.

Gene

A part of the chromosome that determines hereditary characteristics.

Genetics

The study of heredity.

Genitals, genitalia

Reproductive organs.

Geriatrics

The branch of medical science devoted to diseases of the aged.

Germ

Microorganism usually associated with causing disease.

Germicide

Germ-killing agent.

Gerontology

The study of aging and the diseases associated with it.

Gestation

Pregnancy.

Gingivitis

Inflammation of the gums.

Gland

Any organ that produces and secretes a chemical substance used by another part of the body. Ductless, or endocrine, glands secrete into the bloodstream. Secretions of exocrine glands are transported through ducts or excreted directly to a particular location.

Glandular fever

Infectious mononucleosis.

Glans penis

The head of the penis.

Glaucoma

A disease of the eye in which increased pressure within the eye damages the retina and optic nerve. Leads to impaired sight and sometimes blindness.

Globulin

The portion of blood protein in which antibodies are formed.

Globus hystericus

The feeling of "a lump in the throat" due to hysteria, anxiety, or depression. Sometimes accompanied by difficulty in swallowing.

Glomerulus (glomeruli)

A small tuft of blood capillaries in the kidney, responsible for filtering out waste products.

Glucose (dextrose or blood sugar)

The most common monosaccharide (simple sugar) and the main source of energy for humans. It is stored as glycogen in the liver and can be quickly converted back into glucose.

Glucose tolerance test

Test to determine body's response to a glucose challenge. Used to detect hypoglycemia or diabetes.

Glycogen

Animal starch. The form in which glucose is stored in the liver. Glycogen is easily converted into glucose for body use as energy.

Glycosuria

Sugar in the urine.

Goiter

Enlargement of the thyroid gland, which causes swelling on the front of the neck.

Gonad

Primary sex gland. Ovary in the female; testes in the male.

Gonococci

Kidney-shaped gonorrhea-causing bacteria.

Gonorrhea

A common venereal disease caused by the gonococcus bacterium and characterized by inflammation of the urethra, difficulty in urination (in males), and inflammation of the cervix (in females).

Gout

A metabolic disorder in which an overabundance of uric acid causes urate crystals to form in the joints and sometimes elsewhere.

Graafian follicles

Tiny vesicles in the ovaries that contain ova before release (ovulation).

Graft

Transplantation of tissue or skin from one part of the body to another.

Gram-negative or gram-positive

Method of classifying bacteria according to how they are affected when stained with alcohol.

Grand mal

A severe epileptic attack in which convulsions are accompanied by loss of consciousness.

Granulation

The new skin tissue containing capillaries, blood vessels, and reparative cells that forms in a wound's healing process.

Granulocytes

White blood cells (leukocytes) containing granules. They are manufactured in the bone marrow to digest and destroy bacteria.

Granuloma

A tumor or growth containing granulation tissue.

Granuloma inguinale

A contagious venereal disease characterized by ulcers on the genitals.

Gravel

Fine, sandlike particles composed of the same substance as kidney stones but usually passed in the urine without notice.

Graves' disease

One form of hyperthyroidism or an overactive thyroid gland, usually accompanied by abnormalities of the eyes and skin.

Gravid

Pregnant.

Greenstick fracture

Incomplete fracture due to the pliability of the bone. Usually occurs in children whose bones are still growing.

Grippe

Influenza.

See

Cartilage.

Groin

The lower abdominal area where the trunk and thigh join. Also called the inguinal area.

Gumma

A fibrous tumor filled with a rubberlike substance that occurs in the brain, liver, or heart in the late stages of syphilis.

Gynecology

The branch of medical science that deals with the normal functioning and diseases of women's reproductive organs.

Gynecomastia

Abnormal enlargement of the male breasts.

Halitosis

Technical term for bad breath.

Hallucination

A false perception believed to be real but actually having no basis in fact.

Hallucinogen

Agent capable of producing hallucinations; psychedelic drug.

See

Bunion.

Hallux

The big toe.

Hammertoe

A permanent hyperextension of the toe, which cannot be flattened out.

Hamstring

Group of tendons at the back of the knee.

Harelip

Congenital defect of the lip due to a failure of bones to unite and causing a split from the margin of the lip to the nostril.

Hay fever

An allergic reaction to pollen in which mucous membranes of the eyes, nose, and throat become inflamed.

Hearing aid

Device used to amplify sounds for those with hearing difficulties.

Heart

The muscular organ that pumps blood through the body. It is situated between the two lungs and behind the sternum.

Heart attack

Myocardial infarction. Damage to part of the heart muscle caused by interruption of the blood circulation in the coronary arteries.

Heart block

A condition in which an abnormality in the tissues connecting the heart chambers interferes with the normal transmission of electrical impulses and may lead to disturbances in the heart's rhythm or pumping action.

Heartburn

Burning sensations in the upper abdomen or behind the sternum. Usually caused by the regurgitation of gastric juices into the esophagus.

See

Congestive heart failure.

Heart-lung machine

An apparatus that takes over for the heart during open-heart surgery. The blood bypasses the heart and is oxygenated in the machine and pumped back into the body.

Heart murmur

Any of various sounds heard in addition to the regular heartbeat. Often associated with a diseased heart valve, but may also have a benign or harmless cause.

Heat exhaustion

Collapse, with or without loss of consciousness, due to extreme heat conditions and loss of salt through sweating. In attempts to cool down the body surface, blood accumulates close to the skin, thus depriving the vital organs of full blood supply.

Heat stroke

An emergency condition in which the sweating mechanism of the body fails, resulting in an extremely high body temperature.

Hemangioma

A malformation of blood vessels that appears as a red, often elevated mark on the skin. It may be present at birth and may require treatment if it fails to disappear on its own.

Hematemesis

Vomiting of blood.

Hematology

The scientific study of blood.

Hematoma

A blood-filled swelling resulting from blood vessels injured or ruptured by a blow.

Hematuria

The presence of blood in the urine.

Hemiplegia

Paralysis affecting one side of the body.

Hemochromatosis

Abnormal accumulation of iron deposits in the body as a result of a metabolic disturbance. Symptoms include a bronzing of the skin, diabetes, and cirrhosis of the liver.

Hemodialysis

Removal of waste materials from the blood. The artificial kidney performs this function.

Hemoglobin

The red pigment contained in red blood cells and combining the iron-containing heme with the protein-containing globin. Hemoglobin is responsible for transporting oxygen to body tissue and removing carbon dioxide from body tissue.

Hemolysis

Breaking down of red blood cells.

Hemophilia

An inherited blood disorder in which the blood is unable to clot, causing severe bleeding from even minor wounds. The disease affects primarily males but is passed on by female carriers.

Hemoptysis

Spitting up blood.

Hemorrhage

Abnormal bleeding due to rupture of a blood vessel.

Hemorrhoids (piles)

Varicose veins in and around the rectal opening. Hemorrhoid symptoms include pain, bleeding, and itching.

Hemostat

An instrument that prevents bleeding by clamping a blood vessel.

Heparin

Anticoagulant substance that is found in the liver and other tissues. It is sometimes administered to prevent blood clots. It also may be used to treat a threatened stroke, thrombophlebitis, and various clotting diseases.

Hepatitis

Inflammation of the liver, usually due to a viral infection but can also be the result of alcoholism and other conditions. Hepatitis B is transmitted through blood contact (e.g., contaminated hypodermic needles or transfused blood from a hepatitis B carrier). Hepatitis A is transmitted through fecal contact, usually from contaminated food. Hepatitis C (formerly non-A, non-B) is not as well understood as the other two.

Hepatoma

Tumor of the liver.

Heredity

The transmission of traits from parents to offspring. Genetic information is carried by the chromosomes.

Hermaphrodite

An individual possessing both the male and female sex organs.

Hernia

The abnormal protrusion of part or all of an organ through surrounding tissues.

Heroin

An addictive narcotic drug derived from opium and a form of morphine (diamorphine).

Herpes simplex

Recurring infection caused by herpesvirus. Type 1 involves blisterlike sores usually around the mouth and referred to as "cold sores" or "fever blisters." Type 2 usually affects the mucous membranes of the genitalia and can be spread by sexual contact, although either type can cause genital or oral sores.

Herpes zoster (shingles)

A painful viral infection resulting in inflammation and blisters following the path of a nerve. It is caused by the same virus that causes chickenpox, which remains in the body in a latent form and may erupt many years later in an attack of shingles.

Hiatal hernia

A disorder in which a portion of the stomach protrudes through the esophageal opening of the diaphragm and may cause symptoms of indigestion, heartburn, or regurgitation of food.

Hiccups (hiccoughs)

An involuntary spasm of the diaphragm followed by the sudden closing of the glottis, which coincides with the intake of a breath.

See

Hypertension.

Histamine

A chemical found in body tissue and released to stimulate production of gastric juices for digestion. In an allergic reaction, excessive amounts of histamine are produced and cause surrounding tissue to become inflamed. Antihistamines are thus prescribed for relief from allergic attacks.

Hives (urticaria)

Itchy red and white swellings that appear on the skin usually in an allergic reaction.

Hodgkin's disease

A serious disorder of the lymphatic system in which the lymph nodes enlarge. Type of cancer.

Homograft

Tissue or organ transplantation from one individual to another of the same species.

Homosexuality

Sexual desire for those of one's own sex.

Hormone

Secretion from an endocrine gland transported by the bloodstream to various organs in order to regulate vital functions and processes.

Hyaline

A glasslike substance that occurs in cartilage or the eyeball.

Hyaline membrane disease (respiratory distress syndrome)

A condition affecting newborn premature infants in which the air sacs in the lungs are immature and clogged with hyaline, a crystalline material that makes effective breathing difficult or impossible.

Hydrocele

An abnormal accumulation of fluid, usually in the sac of the membrane that covers the testicle.

Hydrocephalus ("water on the brain")

An abnormal increase in cerebral fluid resulting in an enlarged head.

Hydrochloric acid

An acid, composed of hydrogen and chlorine, secreted by the stomach in the process of digestion.

Hydrolysis

Division into simple substance(s) by the addition of water.

Hydrotherapy

Treatment of disease or injury by use of baths or wet compresses.

Hymen

The membrane partially covering the entrance to the vagina.

Hyperchlorhydria

Excessive amounts of hydrochloric acid in the gastric juice.

Hypercholesterolemia

Excessive amounts of cholesterol in the blood.

Hyperemesis

Excessive vomiting.

Hyperemesis gravidarum

Excessive vomiting during pregnancy, commonly referred to as morning sickness.

Hyperglycemia

Excessive amounts of sugar in the blood. One of the indications of diabetes.

Hyperhidrosis

Excessive sweating.

Hyperinsulinism

A condition in which excessive amounts of insulin cause abnormally low blood sugar. Similar to insulin shock.

Hyperkinesis

Hyperactivity; excessive movement or activity.

Hyperopia

Farsightedness.

Hyperplasia

Overgrowth of an organ caused by an increase in the number of normal cells.

Hypertension

High blood pressure; a major risk factor for stroke and heart attack.

Hyperthyroidism

Overactivity of the thyroid gland. Symptoms include weight loss, restlessness, and sometimes goiters.

Hypertrophy

Increased size of a body tissue or organ usually in response to increased activity.

Hypnosis

A trancelike state in which a person's consciousness is altered to make him/her susceptible to suggestion.

Hypnotic

A drug that induces sleep.

Hypochondria

Excessive anxiety about and preoccupation with illness and supposed ill health.

Hypoglycemia

Low blood sugar. Hypoglycemic shock due to insulin overdose is another term for insulin shock.

Hypophysis

The pituitary gland.

Hypospadias

A congenital malformation of the urethra.

Hypotension

Low blood pressure.

Hypothalamus

The part of the brain just above the pituitary gland. It has a part in controlling basic functions such as appetite, procreation, sleep, and body temperature and may be affected by the emotions.

Hypothyroidism

Abnormal inactivity or decrease in activity of the thyroid.

Hysterectomy

Surgical removal of the uterus.

Hysteria

A neurosis, usually due to mental conflict and repression, in which there is uncontrollable excitability or anxiety.

Iatrogenic disease

Any disorder or disease caused as an unintentional side effect of a physician's prescribed treatment.

Ichthyosis

A congenital disorder in which the skin is dry and scaly.

Icterus

Jaundice.

Idiopathic

Peculiar to an individual or originating from unknown causes.

Ileitis

Inflammation of the ileum (lower portion of the small intestine); Crohn's disease.

Ileum

The lower portion of the small intestine.

Ilium

Broad upper part of the hipbone.

Immobilization

Making a bone or joint immovable in order to aid in correct healing.

Immunity

State of resistance to a disease. Active immunity is acquired by vaccination against it or by previous infection. Passive immunity is acquired from antibodies either from the mother through the placenta during gestation or from injection of serum from an animal that has active immunities.

Immunization

The procedure by which specific antibodies are induced in the body tissue.

Impacted

Wedged in tightly and abnormally immovable.

Imperforate

Without normal opening.

Impetigo

Highly contagious inflammatory pustular skin disease caused by staphylococci or streptococci.

Impotence

Inability of the male to achieve penile erection and engage in sexual intercourse.

Incisors

The eight sharp cutting teeth, four in each jaw.

Incontinence

Inability to control release of urine or feces.

Incubation period

The interval of time between contact with disease organisms and first appearance of the symptoms.

Incubator

A temperature- and atmosphere-controlled container in which premature or delicate babies can be cared for. Also a container in which bacteria or other organisms are grown for cultures.

Incus

The small bone of the middle earthat conducts sounds to the inner ear.

Indigestion

An abnormality in the digestive process; dyspepsia.

Induration

Hardening of tissue.

Infarct

An area of dead tissue as a result of a total blockage of the blood supply.

Infertility

Inability to reproduce.

Inflammation

The reaction of tissue to injury, infection, or irritation. Affected area may become painful, swollen, red, and hot.

Influenza (flu)

A contagious viral infection that occurs in epidemics.

Inguinal

Pertaining to the groin.

Inoculation

The intentional introduction of a disease agent to the body in order to induce immunity by causing a mild form of the disease.

Inoperable

Not treatable by surgery.

Insemination

Introduction of semen into the vagina either through sexual intercourse or artificially.

Insomnia

Inability to sleep. Can be chronic or occasional.

Insulin

The hormone produced and secreted by the beta cells of the pancreas gland. Insulin is needed for proper metabolism, particularly of carbohydrates, and the uptake of sugar (glucose) by certain body tissues. Diabetes mellitus is a deficiency of insulin or the inability of the body to use insulin.

Insulin shock

Loss of consciousness caused by an overdose of insulin.

Integument

The skin.

Intention tremor

Involuntary trembling triggered or intensified when movement is attempted.

Interferon

A complex natural protein that causes cells to become resistant to infection.

Intertrigo (chafing)

Superficial inflammation of opposing skin surfaces that rub together.

Intestines

The section of the digestive tract extending from the stomach to the anus.

Intima

The innermost lining of an artery.

Intracutaneous test

Introduction of allergens into the skin in order to test sensitivity to particular substances.

Intrauterine contraceptive device (IUD)

Device made of stainless steel, silkworm gut, or plastic that is inserted by a physician into the uterus to prevent pregnancy.

Intravenous

Into or within a vein.

Intravenous feeding

Nourishment through a glucose solution and other nutrients injected directly into a vein.

Involution of uterus

Shrinking of the uterus to normal size after childbirth.

Iris

The round, colored portion of the eye that surrounds the pupil.

Iritis

Inflammation of the iris.

Iron

The essential mineral micronutrient of hemoglobin.

Iron lung

A respirator. A machine that artificially expands and contracts to facilitate breathing for patients with paralyzed respiratory muscles.

Irreducible

Incapable of being replaced to normal position. Applied to fractured bones or to hernia.

Ischemia

Localized blood deficiency, usually as a result of a circulatory problem. For example, cardiac ischemia results when a coronary artery is so occluded that it cannot deliver sufficient blood to the heart muscle.

Islets of Langerhans

The groups of cells (alpha and beta) in the pancreas that secrete endocrine hormones; the alpha cells produce glucagon and the beta cells produce insulin.

Isotope

A chemical element similar in structure and properties but differing in radioactivity or atomic weight.

Jaundice

Yellow discoloration of the skin and eyes caused by excessive amounts of bile pigments in the bloodstream.

Jejunum

Part of the small intestine situated between the duodenum and the ileum.

Jigger

Sand flea that burrows into skin in order to lay eggs, causing itching and inflammation (also called chigger).

See

Tinea cruris.

Joint

The point where two or more bones connect.

Jugular veins

The two veins on the sides of the neck that carry blood from the head to the heart.

Keloid

An overgrowth of scar tissue after injury or surgery.

Keratin

Substance that is the chief constituent of the horny tissues, such as the outer layer of skin, nails, and hair.

Keratitis

Inflammation of the cornea.

Ketogenic diet

A diet that results in the excessive burning of fat, which can lead to ketosis.

Ketosis

The buildup of ketone bodies, highly acidic substances, in the body. This condition is often associated with diabetes and can lead to a fatal coma.

Kidneys

The two bean-shaped glands that regulate the salt, volume, and composition of body fluids by filtering the blood and eliminating wastes through production and secretion of urine.

Kinesthesia

Perception of movement, position, and weight. Muscle sense.

Klinefelter's syndrome

Chromosomal abnormality in which an individual has 2 X and 1 Y sex chromosomes. As a result, the individual appears to be male but has oversized breasts, underdeveloped testes, and is sterile.

Kneecap

Patella.

Knee jerk

Reflex reaction in which the foot kicks forward in response to a tap on the ligament below the kneecap.

Kwashiorkor

A disease caused by protein deficiency due to malnutrition; occurs mostly in underdeveloped countries. Symptoms include growth retardation, apathy, anemia, and abnormal distention of the abdomen.

Kyphosis

A rounding of the shoulders or hunchback caused by poor posture or disease, such as osteoporosis.

Labia

Liplike organs. Labia majora: two folds of skin and fatty tissue that encircle the vulva. Labia minora: the smaller folds inside the labia majora that protect the clitoris.

Labor (parturition)

The rhythmic muscle contraction in the uterus in the process of childbirth.

Laceration

A wound caused by the tearing of tissue.

Lacrimal ducts (tear glands)

The gland at the inner corner of the eye that secretes tears.

Lactation

Production and secretion of milk by the breasts.

Lactic acid

Acid produced by the fermentation of lactose; a waste product from the muscles.

Lactose

A sugar contained in milk.

Lactovegetarian

Vegetarian who eats dairy products.

Lancet

Small double-edged knife used in surgery.

Lanolin

Fat derived from wool and used as an ointment or lotion base.

Laryngitis

Inflammation of the larynx characterized by hoarseness or complete loss of voice.

Larynx

Voice box. A cartilaginous structure containing the apparati of voice production: the vocal cords and the muscles and ligaments, which move the cords.

Laser

Light Amplification by Stimulated Emission of Radiation.

Laser beam

A beam of intense controlled light that can sever, eliminate, or fuse body tissue.

Laxative

Any agent that encourages bowel activity by loosening the contents.

Lead poisoning

Intoxication from ingestion of lead.

Lecithin

A waxy, fatty compound found in cell protoplasm.

Lens

The transparent tissue of the eye that focuses rays of light in order to form an image on the retina.

Leprosy

An infectious skin disease caused by bacteria and affecting the nerves and skin with ulcers.

Leptospirosis (infectious jaundice)

An infectious disease spread to humans by urine of infected animals. Symptoms include jaundice.

Lesion

Any breakdown of tissue, i.e., wound, sore, abscess, or tumor.

eukemia

A group of diseases of the blood-forming organs in which a proliferation of bone marrow and lymphoid tissue produces an overabun-dance of white blood cells (leukocytes) and disrupts normal production of red blood cells. A form of cancer.

Leukocytes

White blood cells instrumental in fighting infection.

Leukocytosis

Abnormal increase in the amount of white blood cells in the body, often due to the physiological response to infection.

Leukopenia

Abnormal deficiency of white blood cells.

Leukorrhea

Vaginal discharge of mucus. When discharge is heavy, it may be a sign of infection or disease.

Libido

Term used by Freud for the desire for sensual satisfaction. Commonly used to mean sexual desire.

Ligament

The tough, fibrous band of tissue that connects bones.

Ligature

A thread of silk or catgut or wire used to tie off blood vessels to prevent bleeding during surgery.

Lipid

Fat or fatlike substance such as cholesterol or triglycerides.

Lipoma

A benign tumor composed of fat cells.

Lithiasis

Formation of gallstones or kidney stones (calculi).

Litholapaxy

Method of crushing a stone and removal of fragments from the urinary bladder through a catheter.

Lithotomy

Removal of stone by cutting into the bladder.

Lithuresis

Elimination of gravel in the urine.

Liver

The largest internal organ of the body. Among its many functions are secreting bile and digestive enzymes, storing glycogen, neutralizing poisons, synthesizing proteins, producing several blood components, and storing certain vitamins and minerals.

Lobotomy

Surgical disconnection of nerve fibers between the frontal lobe and the rest of the brain. Once commonly used to calm uncontrollable mental patients.

Lochia

Vaginal discharge of blood, mucus, and tissue after childbirth.

See

Tetanus.

Lordosis

Swayback. Condition in which the inward curve of the lumbar spine is exaggerated.

Low blood sugar

Hypoglycemia.

Lues

Syphilis.

Lumbago

Lower back pain.

Lumbar

Lower back between the pelvis and the ribs.

Lungs

Two organs of spongelike tissue that surround the bronchial tree to form the lower respiratory system. Are vital to oxygenation of blood and expulsion of gaseous waste from the body.

Lupus erythematosus

An inflammatory autoimmune disease. Systemic lupus erythematosus involves deterioration of the body's connective tissues.

Lymph

Transparent yellowish fluid containing lymphocytes and found in lymphatic vessels. Lymphatic fluid.

Lymph nodes

Oval-shaped organs located throughout the body that manufacture lymphocytes and filter germs and foreign bodies from the lymph.

Lymphocytes

A disease-fighting type of leukocyte manufactured in the lymph nodes and distributed in the lymphatic fluid and blood.

Lymphogranuloma venereum

A sexually transmitted viral disease that causes sores around genitals and swollen lymph nodes in the male groin.

Lymphosarcoma

Malignant tumor of lymphatic tissue.

Maceration

The softening of tissue in contact with fluid.

Macula

Spot of discolored skin.

Macula lutea

The small, yellow round spot on the retina. Center of color perception and clearest vision.

Malabsorption

Defective absorption of nutrients in the small intestine. Malabsorption syndrome is characterized by steatorrhea (loose fatty stool) or diarrhea, weight loss, weakness, and anemia. May be caused by lesions on the intestine, metabolic deficiencies, or surgery.

Malacia

Softening of a part.

Malaise

A general feeling of illness and discomfort. Tiredness, irritability, and listlessness.

Malaria

A tropical parasitic disease spread by mosquitoes. Symptoms include chills, fever, and sweating.

Mal de mer

Seasickness.

Malignant

Harmful, life-threatening. Used mostly in reference to a cancerous tumor.

Malingering

Deliberate feigning of illness.

Malleus

The largest of the three bones in the inner ear.

Malnutrition

Insufficient nourishment due to poor diet or defect in body's assimilation.

Malocclusion

Failure of the upper teeth to mesh properly with lower teeth.

Malpresentation

Any abnormal position of the fetus in the birth canal.

Mammary gland

Milk-secreting gland of the breast.

Mammography

Diagnostic x-ray ex-amination of the breasts.

Mandible

Lower jawbone.

Mania

Mood of undue elation and excitability often accompanied by hallucinations and increased activity.

Manic-depressive psychosis

A mental illness characterized by alternating periods of depression and mania.

Manubrium

The handle-shaped upper part of the breastbone.

Marijuana

The hemp, or cannabis, plant. A hallucinogenic drug.

Marrow

The soft substance present in bone cavities. Red marrow is responsible for red blood cell production. Yellow marrow is marrow that is no longer involved in making blood cells.

Massage

Rubbing, kneading, and pressing the parts of the body for therapeutic purposes. Massage can stimulate circulation, reduce tension, relax muscles, and reduce pain.

Mastectomy

Surgical removal of breast tissue.

Mastication

Chewing.

Mastitis

Inflammation of the breast.

Mastoid cells

Hollow areas (air cells) located in the middle ear.

Mastoiditis

Inflammation of the mastoid cells usually as a consequence of an untreated ear infection.

Masturbation

Manipulation of the genitals for the purpose of deriving sexual pleasure.

Materia medica

The study of the origin, preparation, and use of medicinal substances.

Maxilla

Upper jaw.

Measles

An acute infectious disease characterized by fever, rash, and inflammation of mucous membranes. It is caused by a virus.

Meatus

Passage or opening.

Meconium

The greenish pasty discharge from the bowels of a newborn baby.

Mediastinum

The space that separates the two lungs and contains the heart, thymus, esophagus, and trachea.

Medicine

1. Science of healing. 2. A therapeutic substance.

Medulla

The center of an organ, gland, or bone.

Medulla oblongata

The brain part connected to the spine.

Megalomania

Delusions of grandeur. Symptom of insanity characterized by an exaggerated self-image.

Melanin

Dark pigment found in hair, skin, and choroid of the eye.

Melanoma

Tumor composed of cells containing melanin. Mostly benign but malignant melanoma is a rare and serious form of skin cancer.

Membrane

A thin layer of lining of tissue.

Menarche

Commencement of first menstrual period.

Meninges

Membranes covering the brain and spinal cord.

Meningitis

Inflammation of the meninges.

Menopause

The period of time in which menstruation decreases and finally stops. The change of life after which a woman is no longer able to reproduce.

Menorrhagia

Unusually heavy menstrual bleeding.

Menstruation

The discharge of blood and tissue from the uterus every 28 days and lasting 4 or 5 days.

Mescaline

A hallucinogen.

Mesencephalon

The midbrain; the region between the cerebrum and the cerebellum.

Mesentery

The folds in the abdominal lining between the intestine and the abdominal wall. They support the abdominal organs and supply them with blood and nerves.

Metabolism

The combination of chemical and physical changes in the body essential for maintaining life processes. Basal metabolism is the minimum amount of energy required to sustain life while resting.

Metastasis

The spread of disease from one body part to another usually by transfer of cells or germs through the blood or lymph.

Methadone

An addictive synthetic narcotic used instead of morphine and administered in drug treatment centers to heroin addicts. Also may be used as a painkiller under some circumstances.

Metritis

Inflammation of the uterus.

Metrorrhagia

Bleeding from the uterus between menstrual periods.

Microtome

A surgical instrument for cutting thin slices of body tissue for study.

Micturition

Urination.

Migraine

Periodic severe headaches typically affecting one side of the head and often accompanied by nausea or vomiting, light sensitivity, and visual distortions. Also referred to as vascular headaches.

Miliaria

Prickly heat, heat rash. Sweat trapped under skin because of gland obstruction. Produces itching, prickling pimples on the skin.

Miosis

Contraction of the pupil of the eye.

See

Abortion.

Mitosis

Cell division.

Mitral valve

The valve that allows oxygenated blood into the left ventricle from the left atrium.

Molar teeth

The grinding teeth at the back of both jaws.

See

Down syndrome.

Moniliasis

Yeast infection usually caused by Candida albicans and affecting the mucous membranes such as the lining of the vagina, mouth, and gastrointestinal tract and the skin and nails.

Monocyte

The largest type of white blood cell.

Mononucleosis, infectious

A communicable disease in which the number of monocytes in the bloodstream increases. Symptoms include fever, swollen lymph nodes, and general malaise.

Mons veneris (or mons pubis)

The pad of fatty tissue that covers the pubic bone of the female.

Morning sickness

Nausea during the early stages of pregnancy.

Morphine

A pain-relieving narcotic derived from the opium plant.

Motor

Pertaining to movement; action.

Mountain sickness

A temporary onset of symptoms of difficult breathing, headache, thirst, and nausea brought on by decreased oxygen in air at high altitudes.

Mucous

Pertaining to mucus.

Mucous colitis

Usually a functional disorder of the bowel characterized by mucus in the stool.

Mucous membrane

Thin layers of tissue containing mucus-secreting glands.

Mucus

The viscid secretion of mucous glands that moistens body linings.

Multiple sclerosis

A degenerative disease affecting the central nervous system and brain, characterized by increasing disability.

Mumps

A contagious disease affecting mostly children. Symptoms include painful swollen glands.

Muscle

Body tissue that has the ability to contract.

Muscular dystrophy

A disease appearing in childhood and characterized by a wasting of the muscles.

Myalgia

Pain in the muscles.

Myasthenia

Muscle fatigue or weakness. Myasthenia gravis is a chronic, progressive disease characterized by weakness of the voluntary muscles, especially those of the eyelids.

Mydriasis

Abnormal dilation of the pupil.

Myelin

The white fatty substance that covers most nerves like a sheath.

Myelitis

Inflammation of the spinal cord or bone marrow.

Myeloma

Malignant tumor of the cells derived from the bone marrow.

See

Heart attack.

Myoma

A tumor of muscle tissue.

Myopathy

Any disease of the muscle.

Myopia

Nearsightedness.

Myringitis

Inflammation of the eardrum.

Myxedema

Thyroid deficiency characterized by a slowdown in metabolism and body function. See Hypothyroidism.

Myxoma

A tumor of the connective tissue containing mucoid cells.

Narcolepsy

Neurological disorder characterized by an irresistible tendency to sleep.

Narcosis

Unconsciousness and insensibility to pain brought on by a drug (narcotic).

Narcosynthesis

A method for treating psychoneurosis in which a hypnotic drug is injected into the patient for the purpose of reviving suppressed memories.

Nares

Nostrils.

Nasopharynx

The part of the pharynx situated over the roof of the mouth.

Nausea

A feeling of sickness in the stomach; sometimes followed by vomiting.

Navel

Umbilicus.

Nearsightedness (myopia)

A defect of the eye in which the eyeball is too convex. This causes light rays to focus in front of the retina, resulting in an inability to see objects clearly at a distance.

Necropsy

Autopsy. Examination after death.

Necrosis

Death and deterioration of tissue surrounded by living healthy tissue.

Neonatal

Pertaining to the newborn (up to 1 month old).

Neoplasm

A new and abnormal growth.

Nephrectomy

Surgical removal of a kidney.

Nephritis

Inflammation of a kidney.

Nephrolith

Kidney stone.

Nephron

The unit of the kidney in which waste is removed from the blood and urine is formed.

Nephrosis

Kidney degeneration without inflammation.

Nerve

A bundle of fibers that carries impulses between the nerve center (the brain and spinal cord) and the other parts of the body. There are five kinds of nerves: cranial, mixed, motor, sensory, and spinal.

Neuralgia

Sharp, stabbing pain in a nerve or along its course. The pain is short-lived but recurring.

Neurasthenia

A nervous condition in which one suffers from fatigue and loss of initiative. Usually accompanied by oversensitivity, restlessness, and uncalled-for irritability.

Neuritis

Inflammation of a nerve.

Neurofibroma

Tumor of nervous and connective tissues.

Neurofibromatosis

A condition in which multiple tumors (neurofibroma) form under the skin or along the course of a nerve.

Neurology

The branch of medicine dealing with the nerves and the central nervous system.

Neuron

A nerve cell.

Neurosis

A nervous disorder, usually related to anxiety, in which there is no functional degeneration of tissue.

Nevus

A congenital pigment or elevated portion of skin; birthmark.

Nictation (or nictitation)

Wink. Rapid blinking of eyelid.

Nightblindness (nyctalopia)

Reduced ability to see at night.

Nitrous oxide

Laughing gas; an inhalant that induces euphoria and dulls the sensation of pain. Often used in dentistry.

Nocturia

Urination at night.

Node

A small protuberance or swelling; a knoblike structure; nodule.

Nucleus

The center part of any cell that is essential for cell growth, nourishment, and reproduction. Except for red blood cells, all human body cells have nuclei.

Nutrient

A substance that provides materials the body needs; provides nourishment.

Nutrition

The combination of processes by which the body or organism receives and uses materials es-sential for growth and maintenance.

Nystagmus

Involuntary and repetitive oscillation of the eyeballs.

Obesity

Excessive weight; body weight more than 20 percent above the average for one's age, height, and bone structure.

Obstetrics

The branch of medical science dealing with pregnancy, childbirth, and neonatal care.

Occipital

Pertaining to the back of the head.

Occlusion

Used in reference to a closure of ducts and blood vessels. In dentistry, it refers to the fitting together of the upper and lower teeth.

Occult

Undetectable by the naked eye.

Ocular

Pertaining to the eye.

Olfactory

Pertaining to the sense of smell.

Oligomenorrhea

Infrequent or scanty menstrual flow.

Oligospermia

Abnormally deficient spermatazoa in the semen.

Oliguria

Deficient urine production.

Omentum

A fold of the peritoneum (membrane lining of the abdomen) that covers and connects the abdominal organs.

Omphalitis

Inflammation of the navel.

Oncology

The scientific study of tumors.

Onychia

Inflammation of the nail matrix, the tissue from which the nail grows.

Onychopagy

Nail-biting.

Ophthalmitis

Inflammation of the eye.

Ophthalmology

The branch of medical science dealing with the eyes and their care.

Ophthalmoplegia

Paralysis of eye muscles.

Ophthalmoscope

An instrument for examining the interior of the eye.

Opiate

Narcotic containing opium. Opiate drugs are used as painkillers, sedatives, or to slow gastric motility.

Optic nerve

The fiber that transmits optic impulses from the retina to the brain.

Orbit

Eye socket.

Orchiectomy (or orchectomy)

Surgical removal of the testicles.

Orchitis

Inflammation of the testicles.

Orgasm

Climax of sexual intercourse.

Orthodontics

The branch of dental science dealing with prevention and correction of teeth irregularities and malocclusions.

Orthopedics

The branch of surgery dealing with diseases, disorders, and injuries to the locomotor system.

Orthopnea

Condition in which breathing can only be facilitated when sitting or standing up.

Orthostatic

Exacerbated by standing erect.

Osmosis

The transfer of substance from one solution to another through a porous membrane that separates them.

Osseous

Composed of or resembling bone tissue.

Ossicle

A tiny bone. The three bones in the inner ear are ossicles.

Ossification

The process of becoming bone or the change of cartilage to bone.

Osteitis

Inflammation of bone.

Osteochondritis

Inflammation of bone and cartilage.

Osteoma

Tumor of bone tissue.

Osteomalacia

A condition in which bones become soft, brittle, flexible, and painful due to a lack of calcium and vitamin D. Similar to childhood rickets.

Osteomyelitis

Inflammation of the bone and marrow resulting from infection.

Osteopathy

A system of treating disease that emphasizes massage and bone manipulation.

Osteoporosis

A condition in which bones become porous, resulting in increased fragility. Associated with the aging process.

Otitis

Inflammation of the ear.

Otorhinolaryngology

Branch of medical science that deals with the ear, nose, and throat.

Ovariectomy

Surgical removal of an ovary or ovaries.

Ovary

The female reproductive gland whose function is to produce the eggs (ova) and the sex hormones estrogen and progesterone.

See

fallopian tubes.

Ovum

The egg cell. The female sex cell, which, when fertilized by the male sperm, grows into a fetus. The egg contains 23 chromosomes that pair off with 23 chromosomes in the sperm to make a complete set needed to start a new life.

Oxygen

The colorless, odorless gas that is essential for life. Oxygen makes up about 20 percent of the air.

Oxygenation

The saturation of a substance with oxygen.

Oxyhemoglobin

Oxygen-carrying hemoglobin.

Oxytocin

A pituitary hormone that is secreted during childbirth for the stimulation of uterine contractions and milk secretion. A synthetic form of oxytocin is administered sometimes to induce or hasten labor.

Ozone

A form of oxygen that is used as a disinfectant.

Pacemaker (sino-atrial node)

A small knot of tissue (node) in the right atrium of the heart from which the contraction of the heart originates. Artificial or electronic pacemakers are small, battery-operated devices that can substitute for a damaged pacemaker.

Pachydermia

Abnormal thickening of the skin.

Paget's disease

1. A type of breast cancer in which the nipple becomes sore and ulcerated. 2. Osteitis deformans. A chronic bone disease in which rates of bone production and bone loss are increased, leading to thickened and softened bones.

Palate

The roof of the mouth.

Palliative

Any agent that relieves pain and symptoms of disease but does not actually cure it.

Palpate

Examine by feeling with the hand.

Palpitation

Rapid, throbbing heartbeat.

Palsy

Paralysis.

Pancarditis

Inflammation of all the structures of the heart.

Pancreas

The gland situated behind the stomach that secretes pancreatic juice and enzymes to aid in food digestion. Also contains groups of specialized cells (islets of Langerhans) that secrete insulin and glucagon hormones that regulate blood sugar levels.

Pancreatitis

Inflammation of the pancreas.

Pantothenic acid

One constituent of the vitamin B complex.

Papanicolaou smear (Pap test)

The microscopic examination of cells shed from body surfaces; used routinely to screen for cancer of the cervix or uterus.

Papilla

A small conical or nipple-shaped elevation.

Papilloma

A tumor, usually benign, of the skin or mucous membrane.

Papule

Small abnormal solid elevation on the skin.

Paralysis

Loss of nervous function or muscle power due to injury or disease of the nervous system.

Paranoia

A mental illness characterized by delusions of being persecuted or conspired against.

Paraplegia

Paralysis affecting both legs, usually due to disease of the spinal cord or injury.

Parasite

An organism that lives in or on another organism (host).

Parathyroid glands

Four small glands embedded in the thyroid gland. The hormones secreted by the parathyroids control the body's calcium and phosphorus levels.

Paratyphoid fever

An infectious disease whose symptoms resemble those of typhoid fever but are less severe.

Paregoric

An opium compound that slows gastric action, thereby relieving cramps or diarrhea.

Parenchyma

The parts of an organ that are directly related to the function of the organ (as opposed to supporting or connective tissues).

Parenteral

A substance administered by injection or directly in the bloodstream rather than orally.

Paresis

Slight paralysis.

Parkinson's disease (Parkinsonism)

A disorder in which the patient suffers from tremors, stiffness, and slowness of movement.

Paronychia

Infection of the tissues surrounding a nail.

Parotid gland

One of the salivary glands located near the ear.

Parotitis

Mumps; a viral disease characterized by the swelling of the parotid glands.

Paroxysm

A sudden but temporary attack of disease or symptoms.

See

Psittacosis.

Parturition

Childbirth.

Pasteurization

A process in which disease-causing bacteria in milk or other liquids are destroyed by heat.

Patch test

A diagnostic procedure in which a suspected allergen is injected (in a diluted form) into the skin.

Patella

Kneecap.

Pathogen

Any disease-causing agent.

Pathology

The science dealing with disease, its nature, and causes.

Pectoral

Pertaining to the chest.

Pediatrics

The branch of medical science dealing with children and the diseases affecting them.

Pedicle

Stem of a tumor.

Pediculosis

Lice infestation.

Pellagra

A disease due to a lack of vitamin B2 (nicotinic acid). Symptoms include skin rashes, weakness, and mental confusion.

Pelvis

1. A basin-shaped cavity, such as that of the kidney. 2. The bony basin-shaped cavity formed by the hip bone and the lower bones of the back.

Pemphigus

A serious skin disease in which groups of large blisters on the skin rupture.

Penis

The external male sex organ through which urine is passed and semen is ejaculated.

Pepsin

A protein-digesting enzyme secreted by the stomach in gastric juices.

Peptic

Pertaining to pepsin.

Peptic ulcer

Ulcer in the stomach, duodenum, or esophagus that is related to pepsin.

Percussion

A method of physical diagnosis by tapping or thumping a body part to produce sounds that indicate the size, density, and position of organs.

Perforation

A hole or puncture, usually made by injury or infection (as of the eardrum) or by an ulcer.

Pericarditis

Inflammation of the pericardium.

Pericardium

The two-1ayer membranous tissue covering the heart. The layer closest to the heart is called the visceral layer. The other is the parietal layer.

Perineum

The area between the anus and the genitals.

Periodontal membrane

The tissue around the teeth covering the roots and connecting them to the jaw.

Periodontitis

Inflammation of the periodontal membrane.

Periosteum

The tough, fibrous membrane covering nearly all bone surfaces.

Peristalsis

A wave of muscular contractions that push materials along the digestive tract.

Peritoneum

The serous membrane that lines the abdominal organs.

Peritonitis

Inflammation of the peritoneum.

Perleche

A condition in which the corners of the mouth become cracked, raw, and thickened due to vitamin deficiency, bacterial infection, or other causes.

Pernicious

Deadly, life-threatening.

Pernicious anemia

Anemia caused by a deficiency of vitamin B2 or an inability of the body to absorb vitamin B2.

Perspiration

Sweat; the secretion of the sweat gland through the pores of the skin.

Pertussis

Whooping cough.

Pessary

1. A device placed in the vagina to support the uterus or correct uterine displacements. 2. A vaginal suppository.

Petechiae

Small hemorrhages under the skin.

Petit mal

A form of epilepsy or seizure in which the person does not lose consciousness.

Phagocyte

A cell that is capable of engulfing bacteria and debris.

Phalanx

One of the bones in the finger or toe.

Phallus

Penis.

Pharyngitis

Sore throat; inflammation of the pharynx.

Pharynx

The mucous membranelined cavity at the back of the mouth. It extends to the esophagus.

Phimosis

A condition in which the foreskin tightens so it prevents retraction over the head of the penis.

Phlebectomy

Surgical removal of a vein.

Phlebitis

Inflammation of a vein.

Phlegm

Mucus, sputum.

Phobia

An abnormally excessive and irrational fear. Some common phobias are acrophobia, fear of high places; agoraphobia, fear of open places; algophobia, fear of pain; claustrophobia, fear of closed places; ocholophobia, fear of crowds; triskaidekaphobia, fear of the number 13; and xenophobia, fear of strangers.

Physiology

The study of cells, tissues, and organs; their functions and activities.

Pia or pia mater

The innermost layer of the meninges that covers the brain and spinal cord.

Pica

The craving or consumption of unusual substances that ordinarily are not food, such as dirt, chalk, or paint chips.

Pigment

Any coloring matter.

See

Hemorrhoids.

Pimple

Common term for a pustule or papule.

Pineal body

A small gland, conical in structure, located on the back of the midbrain. Its function is not fully understood, but it may be concerned with regulation of growth or of the sex glands.

Pinkeye

Contagious conjunctivitis.

Pituitary gland

The pea-size gland located at the base of the brain. It is controlled by the hypothalamus, and it in turn controls the hormone productions in many other endocrine glands.

Pityriasis

A skin disease in which patches of skin become red and scaly.

Placebo

A substance without medicinal properties that is administered for psychological benefit or as part of a clinical research study.

Placenta

The structure developed on the uterine wall about the third month of pregnancy. Through the placenta, the fetus receives nourishment and oxygen and eliminates waste products. It is expelled from the mother after childbirth. The afterbirth.

Plague

Any deadly contagious epidemic disease.

Plantar

Pertaining to the sole of the foot.

Plaque

Patch or film of organic substance on tissues, such as teeth or in arteries.

Plasma

The fluid part of blood. See Blood plasma.

Platelet (thrombocyte)

The colorless bodies in the blood instrumental in blood clotting.

Pleura

The membrane lining the chest cavity and covering the lungs.

Pleurisy

Inflammation of the pleura.

Plumbism

Lead poisoning.

Pneumococcus

The oval-shaped bacterium responsible for diseases such as pneumonia, meningitis, and otitis media.

Pneumonia

Infection of the lungs.

Pneumonitis

Inflammation of lung tissue.

Pneumothorax

Lung collapse due to air or gas in the chest cavity.

Pollinosis

An allergic reaction to plant pollens inhaled with the air.

Polyarteritis

Inflammation of a number of arteries.

Polycythemia

An overabundance of red blood cells in the blood.

Polydipsia

Excessive thirst, such as that which occurs in untreated diabetes.

Polyopia

Seeing multiple images of a single object.

Polyp

A nodular tumor, usually benign, that grows on a mucous membrane.

Polyphagia

Excessive eating.

Postpartum

After childbirth.

Preeclampsia

A toxic condition of pregnancy characterized by high blood pressure, edema, and kidney malfunction.

Premenstrual syndrome (PMS)

A variety of symptoms, both physical and emotional, associated with the menstrual cycle.

Prepuce

The foreskin of the penis.

Presbycusis

The normal decrease in hearing ability as one gets older.

Presbyopia

Increasing inability to see objects close up. Normal condition of midlife and getting older.

Prickly heat (miliaria)

Skin irritation or rash caused by perspiration.

Proctitis

Inflammation of the membranes of the rectum.

Proctoscope

A tubular instrument for examination of the interior of the rectum.

Progesterone

The female sex hormone that causes the thickening of the uterine lining and the other body changes before conception.

Prognosis

Prediction or forecast of the probable course and/or results of a disease.

Prolactin

Hormone secreted by the pituitary that stimulates the breasts to produce milk.

Prolapse

Downward displacement of an organ from its usual position.

Prophy1axis

Prevention of disease or its spread.

Prostaglandins

Hormonelike substances, secreted by a wide range of body tissues, that perform varying functions in the body.

Prostatectomy

Surgical removal of all or part of the prostate gland.

Prostate gland

The male sex gland located at the base of the bladder.

Prosthesis

An artificial replacement for a missing body part.

Proteins

Complex nitrogen compounds made up of amino acids. Most of the tissues of body, especially the muscles, are composed primarily of protein.

Prothrombin

A substance in the blood that forms thrombin, an enzyme essential to blood coagulation.

Protoplasm

"The stuff of life" in cells. The essential jellylike substance in all living cells.

Protozoa

One-celled organisms, the smallest type of animal life. Amoeba and paramecia are protozoa. Some protozoa can cause disease.

Prurigo

A chronic skin disease characterized by small papules and intense itching.

Pruritis

Itching.

Psittacosis (parrot fever)

A disease similar to pneumonia and transmitted to humans by birds, such as pigeons.

Psoriasis

A chronic skin disease characterized by an overgrowth of the epidermis in which scaly lesions appear on various parts of the body.

Psychiatry

The branch of medical study dealing with mental health.

Psychoanalysis

A method developed by Sigmund Freud for the diagnosis and treatment of mental illness. The patient recalls past, perhaps forgotten, events in order to gain insight into the unconscious mind.

Psychogenic

Originating from the mind.

Psychology

The study of the mind and behavior.

Psychomotor

Voluntary movement.

Psychoneurosis

A mild emotional or mental disturbance, usually a defensive overreaction to unresolved conflicts.

Psychopathy

Any disease of the mind.

Psychosis

A mental illness originating in the mind itself rather than from environmental factors.

Psychosomatic

Any condition either caused or exacerbated by emotional factors.

Psychotherapy

Treatment of mental disorders based on verbal communication with the patient.

Ptomaine

A poisonous substance produced by the decay of protein.

Ptosis

A drooping, especially of the eyelid.

Ptyalin

An enzyme contained in the saliva that initiates the breakdown of starch.

Puberty

The age at which secondary sex characteristics develop and reproductive organs become functionally active. In girls, puberty is marked by the onset of menstruation and in boys by the discharge of semen and the change of voice.

Puerperium

The period of time directly after childbirth until the time when the uterus has returned to its normal state.

Pulmonary

Pertaining to the lungs.

Pulse

The expansion and contraction of an artery as a response to the expansion and contraction of the heart.

Pupil

The opening in the middle of the iris of the eye that allows the passage of light to the retina.

Purgative

A drug inducing evacuation of the bowels. A cathartic or strong laxative.

Purpura

A disorder in which hemorrhages of tiny blood vessels cause purple patches to appear on the skin and mucous membranes.

Purulent

Containing pus.

Pus

A thick, yellowish fluid containing bacteria and white blood cells. Formed in some types of infection.

Pyelitis

Inflammation of the kidney pelvis.

Pyorrhea

The discharge of pus, usually from the teeth sockets.

Pyrexia

Fever.

Pyrosis

Heartburn.

Pyuria

Pus in the urine.

Q fever

A mild infectious disease caused by a rickettsia germ. It is usually transmitted from cows and sheep to humans by contaminated milk, tick bites, or contaminated food products.

Quadriplegia

Paralysis of the arms and legs.

Quarantine

The isolation of persons who might be sick with or have come in contact with a communicable disease.

Quickening

The stage of pregnancy in which the first fetal movements are felt by the mother, usually around the 18th week of pregnancy.

Quinsy

Acute inflammation of the tonsils accompanied by abscess.

See

Tularemia.

Rabies

A deadly disease of the central nervous system caused by the rabies virus and spread by the bite of an infected (rabid) dog or other animal. Hydrophobia.

Radiation sickness

Nausea and diarrhea caused by exposure to moderate radiation. Exposure to massive doses is extremely serious and perhaps fatal.

Radioactive

Giving off penetrating energy waves to produce electrical or chemical effects.

Radioisotope

An element whose atomic number is the same as another but whose atomic weight differs. Radioisotopes can be injected into the body and traced with monitors for diagnostic purposes.

Radium

A highly radioactive metal used to treat cancer.

Rales

Abnormal sounds from the lungs or bronchi.

Rash

Eruption on the skin.

Rat-bite fever

An infectious disease caused by bacteria spread to humans by rat bites.

Raynaud's disease

A disease in which blood vessels of the fingers and toes constrict on exposure to cold, causing numbness and pallor. Blood vessels then expand, causing the area to tingle and become red or purple as the blood returns.

Recessive

A term used in genetics to describe the weaker of two hereditary traits.

Rectum

The portion of the large intestine closest to the anal opening. It consists of the rectal canal and the anal canal.

Reflex

An unconscious, automatic response to a stimulus.

Refractory

Not reacting to treatment.

Regeneration

Repair or renewal of tissue.

Regurgitation

Backflow.

Relapsing fever

Recurrent fever as a symptom of infection caused by bacteria carried by lice and ticks.

Remission

An easing of the symptoms of disease.

Renal

Pertaining to the kidneys.

Renin

An enzyme found in the kidney and capable of raising blood pressure.

Rennin

The enzyme contained in the gastric juice that digests milk.

Repression

The refusal of the conscious mind to acknowledge unacceptable or conflicting thoughts, feelings, or ideas.

Resection

Removal of a part of an organ or tissue by means of surgery.

Respiration

Breathing.

See

Hyaline membrane disease.

Resuscitation

Restoration of breathing or heartbeat to one who is apparently dead or threatened with death.

Reticuloendothelial system

A network of tissues containing cells (phagocytes) capable of taking up bacteria and foreign bodies in the bloodstream.

Retina

The layered lining of the eye that contains light-sensitive receptors (the rods and cones) and conveys images to the brain.

Retinoblastoma

A malignant tumor of the retina occurring in infants and children only.

Retinopathy

An injury or disease of the retina, particularly common in insulin-dependent diabetes.

Retractors

Devices used to pull back the edges of a wound.

Rh factor

A group of antigens in the blood. Some people lack the Rh factor and are therefore designated as Rh negative. Complications can oc-cur if an Rh-negative mother conceives and has an Rh-positive baby. See Erythroblastosis fetalis.

Rheumatoid factor

Abnormal protein in the blood of most people afflicted with rheumatoid arthritis or other autoimmune diseases.

Rhinitis

Inflammation of the mucous membrane of the nose, usually as a symptom of the common cold or allergies.

Rhinoplasty

Plastic surgery of the nose.

Rhinovirus

Any of the more than 100 viruses that cause the common cold.

Rhodopsin

The visual purple in the rods of the retina. It becomes bleached when exposed to light and requires vitamin A for regeneration.

Riboflavin

Vitamin B2.

Rickets

A childhood disease caused by a deficiency of vitamin D. Symptoms include improper development of bones and teeth because of a calcium/phosphorus imbalance.

Rickettsia

Disease-causing microorganisms, smaller than bacteria but larger than viruses. Usually transmitted to humans by the bites of fleas, lice, and ticks.

Rickettsial pox

A rickettsial disease spread by the bites of mites. Symptoms include a poxlike rash, headache, and fever.

Ringworm

A fungal infection affecting the tissues of the skin, hair, nails, and scalp. Dermatophytosis is the general medical name and examples of ringworm infections are tinea pedis (athlete's foot) and tinea capitis of the scalp.

Rocky Mountain spotted fever

A rickettsial disease spread by ticks. Symptoms include fever, headache, muscle pain, and rash.

Rods

Cylindrical nerve structures in the retina. They contain rhodopsin, and together with the cones they perceive the images of light, dark, and color, which are transmitted to the brain.

Roentgen rays

X-rays.

Root canal

The nerve-containing passageway through the root of the tooth.

Rose fever

An allergic reaction to roses; term often used to describe pollen and/or mold allergies that occur during the spring as opposed to hay fever, which is in the fall.

Roseola

Any pink eruption on the skin.

Roughage

Indigestible matter (such as fiber).

Roundworms

Parasites found in contaminated feces. In humans, roundworms cause ascariasis, a condition whose symptoms include disruption of the digestive system and abdominal pain.

Rubella

German measles.

Rubeola

Measles.

Rupture

A tearing or bursting of a part. Also, a hernia.

Saccharin

A sugar substitute derived from coal tar.

Sacroiliac

The joint connecting the base of the spine to the upper part of the hip bone.

Sacrum

The triangular bone just above the coccyx, near the lower end of the spine. It is composed of five vertebrae that have fused together. Together with the bones of the pelvis it forms the sacroiliac joint.

See

Erysipelas.

See

Chorea.

Saline

Salty.

Saliva

The secretion of the salivary glands. Lubricates the mouth and throat and initiates the digestion of food with enzymes.

Salivary glands

The three glands on each side of the face. The sublingual gland and submaxillary gland secrete saliva onto the floor of the mouth. The parotids are situated near the ears and secrete saliva through passageways in the back of the mouth.

Salmonella

A group of bacteria primarily responsible for the gastrointestinal disturbances of food poisoning.

Salpingectomy

Surgical removal of the fallopian tubes; tubal ligation; a method of sterilization.

Salpingitis

Inflammation of the fallopian tubes.

Sarcoma

A malignant tumor from connective tissue.

Scabies

Infestation of the skin by parasites (scabies mites) that burrow under the skin surface to lay their eggs. "The itch."

Scapula

The shoulder blade.

Schick test

A skin test for immunity to diphtheria.

Schizophrenia

Dementia praecox. A group of mental illnesses classified as psychotic (rather than neurotic). Patient's thought patterns become disturbed and disorganized, and hallucinations or delusions are common symptoms.

Sciatica

Pain extending along the path of the sciatic nerve. Can be caused by a slipped disk or by a muscle spasm.

Sciatic nerve

The largest nerve in the body. It branches out from the base of the spinal cord (where it is attached) to form the motor and sensory nerves of the legs and feet.

Sclera

The fibrous outer coat of the eye.

Sclerosis

Abnormal hardening or thickening of a tissue.

Scoliosis

Curvature of the spine.

Scorbutus

Scurvy.

Scotoma

Any (normal or abnormal) blind spot in the field of vision.

Scrotum

The pouch that holds the testicles in the male.

Scurvy

A disease caused by a deficiency of vitamin C. Symptoms include anemia, weakness, and bleeding gums.

Sebaceous glands

The oil glands that secrete sebum, a fatty substance to lubricate the skin.

Seborrhea

Overactivity of the sebaceous glands resulting in a greasiness of the skin.

Sebum

The fatty substance secreted by the sebaceous glands.

Secretion

Any substance formed or emitted by glands or tissue. Various secretions perform various functions for the body.

Sedative

An agent that calms and reduces excitability.

Semen

The thick, whitish secretion produced by the male testes and sex glands and containing the male reproductive cells, the spermatozoa.

Semicircular canals

The three membranous canals of the inner ear that control the sense of balance.

Seminal vesicles

The two glands that store the spermatozoa.

Senescence

The process of aging; growing old.

Senility

Abnormal deterioration of mental function associated with increasing age. Many physical diseases, such as arteriosclerosis, may be associated with senility.

Sepsis

The state of being infected by germs in the blood or tissues.

Septicemia

Blood poisoning. The presence of living bacteria in the bloodstream.

Septum

A dividing wall between two compartments or cavities.

Serum

The fluid formed in the clotting of blood. Contains antibodies and is injected in vaccines to build up immunities to specific diseases.

Serum sickness

An allergic reaction (usually hives and fever) to the injection or administration of serum.

Shingles (herpes zoster)

A virus infection of nerve endings characterized by pain and blisters along the course of the nerve. Caused by a latent form of the same virus that causes chickenpox, usually years after that disease.

Shock

A condition in which the body processes slow down in response to injury or extreme emotion. Symptoms include rapid pulse, low blood pressure, paleness, and cold, clammy skin.

Sickle cell anemia

A hereditary type of anemia caused by malformed (crescent-shaped) red blood cells.

Siderosis

Chronic inflammation of the lungs caused by inhaling iron particles. An excess of iron in the circulating blood.

Silicosis

Inflammation and damage of the lung caused by silicon dioxide. It is an occupational disease associated with sand blasting and stone cutting.

Sinus

A cavity, hollow space, especially of the nasal passages.

Sinusitis

Inflammation of a sinus.

Smegma

Thick sebaceous secretion that accumulates beneath the prepuce and clitoris.

Solar plexus

A network of nerves in the abdomen.

Somnambulism

Sleepwalking.

Somniloquy

Talking in sleep.

Spasm

Sudden and severe involuntary contraction of a muscle.

Speculum

An instrument used to dilate a body passage in order to examine the interior, such as the examination of the vagina and cervix during a pelvic examination.

Spermatocele

Enlargement of the scrotum due to the development of a fluid-filled sac (cystic dilation) of the tubules.

Spermatozoa

Male reproductive cell. See Ovum.

Spermicide

An agent that kills spermatozoa.

Sphincter

A ring of muscle that encircles and controls the opening of an orifice.

Sphygmomanometer

An instrument used to measure blood pressure.

Spina bifida

A congenital defect in which some of the vertebrae fail to close and therefore expose the contents of the spinal canal.

Spinal canal

The central hollow formed by the arches of the vertebrae that contains the spinal cord.

Spinal column

The structure formed from the 33 vertebrae (spinal bones); the backbone.

Spinal cord

The cord or column of nerve tissue extending from the brain, enclosed in the spinal canal.

Spinal nerves

31 pairs of nerves that pass out of the spinal cord and carry impulses to and from all parts of the body.

Spinal tap

The withdrawal of cerebrospinal fluid for the purpose of diagnosis or relief of pressure on the brain; lumbar puncture.

Spirochete

Spiral-shaped bacterium. Syphilis is caused by a spirochete.

Spleen

A large lymphoid organ behind the stomach on the lower left side of the rib cage. Its function includes cleansing the blood of parasites and manufacturing lymphocytes.

Spondylitis

Inflammation of the spine.

Spore

A life stage in the cycle of certain microorganisms in which they become inactive and highly resistant to destruction. A spore can become active again.

Sprain

Injury to the soft tissue around a joint.

Sprue

A chronic malabsorption disorder in which the body cannot absorb fats. Symptoms include diarrhea, indigestion, weight loss, and soreness in the mouth.

Sputum

Discharge from the lungs and throat composed of mucus and saliva.

Stapes

A tiny stirrup-shaped bone in the inner ear.

Staphylococci

Spherical bacteria occurring in clusters. Responsible for food poisoning and skin infections; staph infections.

Steatorrhea

Pale, bulky stools containing undigested fats.

Stenosis

A narrowing of a body passage, tube, or opening.

Sterile

1. Germ-free. 2. Unable to re-produce.

Sternum

The breastbone. The bone in the middle of the chest.

Steroids (corticosteroids, cortisone)

Natural hormones or synthetic drugs that have many different effects. Some steroids are anti-inflammatory and are used to treat arthritis, asthma, and a number of autoimmune disorders.

Stethoscope

An instrument that amplifies bodily sounds.

Stillborn

Term used to describe a baby born dead after the 20th week of pregnancy.

Stomach

The pouchlike organ into which the food flows from the esophagus. Digestion takes place here by means of enzymes and hydrochloric acid and also the churning action of the stomach muscles.

Stomatitis

Inflammation of the soft tissues of the mouth; canker sore.

Stool

Feces. Evacuation of the bowels.

Strabismus

An eye disorder in which both eyes are unable to focus simultaneously; cross-eyed.

Strain

Injury caused by misuse or overuse of a muscle.

Strawberry tongue

A bright red tongue with enlarged papillae; associated with scarlet fever.

Streptococci

Spherical bacteria that grow in chains. They are responsible for infections like scarlet fever and strep throat.

Striae

Stripes, narrow bands. Stretch marks are a common example.

Stroke

An interruption of the blood flow to the brain causing damage to the brain. Depending on the severity and location of the stroke, it may result in partial or complete paralysis or loss of some bodily function, or death.

Stroma

The supporting tissue of an organ as opposed to the functioning part. See Parenchyma.

Stupor

A state of impaired but not complete loss of consciousness and responsiveness.

Sty

Infection of one of the sebaceous glands of the eye.

Subconscious

The contents of the mind not in the range of consciousness.

Subcutaneous

Under the skin.

Sulfonamides

Sulfa drugs. A group of medicines that were the first antibiotic drugs.

Sunstroke

Failure of the body's temperature control system as a result of overexposure to high heat and humidity. Body temperature rises to a very high degree, leading to coma and death. See Heat stroke.

Suppository

Medicated substance in solid form for insertion into a body opening, usually the vagina or rectum. It melts inside the body to release the medicine.

Suppuration

Pus formation.

See

Adrenal glands.

Suture

1. To join two surfaces by stitching. 2. The threadlike substance used to join two surfaces.

Sympathectomy

Surgical removal of part of the sympathetic nervous system.

Sympathetic nervous system

Part of the autonomic nervous system. A chain of spinal nerves whose functions include contraction of blood vessels, increase of heart rate, and regulation of glandular secretions.

Synapse

The point of communication between nerve endings.

Syncope

Fainting.

Syndrome

A group of symptoms that occur together, presumably originating from the same cause.

Synovia

The viscid fluid that lubricates joints.

Systole

The contraction of the heart muscle. Systolic pressure is the greater of the two blood pressure readings (the other is diastolic).

Systolic murmur

An abnormal sound heard during the contraction of the heart.

Tachycardia

Excessively rapid heartbeat.

Talipes (clubfoot)

Congenital deformity in which the foot is twisted out of the normal position.

Tampon

A plug of cotton or other absorbent material that is inserted into a body cavity in order to soak up discharge, such as vaginal tampons to absorb menstrual flow.

Tartar

Calcified deposits on the teeth that are from a buildup of plaque.

Tay-Sachs disease

A congenital disease affecting the fat metabolism and the brain and characterized by progressive weakness, disability, and blindness, and finally death. Also known as amaurotic familial idiocy.

T cells

A specialized type of white blood cell (lymphocyte) that works as part of the immune system by attaching itself directly to an invading organism, such as a parasite or fungus, and destroying it. See B cell.

Temple

The portion of the head between the eye and the ear.

Tendinitis

Inflammation of a tendon.

Tendon

A white fibrous band that connects muscle to bone.

Tenesmus

Urgent desire to evacuate the bowel or bladder with painful and ineffectual straining to urinate or to move the bowels.

Tensor

A muscle that stretches or tenses.

Testicles, testes

The pair of primary male sex glands enclosed in the scrotum. They produce the male sex hormone testosterone and the spermatozoa.

Testosterone

The male sex hormone that induces the secondary sex characteristics.

Tetanus (lockjaw)

A serious and acute infection caused by the invasion of toxic microorganisms into an open wound.

Tetany

Muscular spasms and cramps due to muscular hypersensitivity. Causes include gastrointestinal disorders or calcium deficiency.

Thalamus

An egg-shaped mass of gray matter at the base of the cerebrum.

Thermometer

Instrument used to measure temperature.

Thiamine

(vitamin B1) One of the B-complex vitamins.

Thoracic

Pertaining to the chest.

Thorax

The chest.

Thrombin

An enzyme that converts fibrinogen into fibrin, which is necessary in order for blood to clot.

Thrombocyte

Blood platelet, necessary for the process of blood clotting.

Thrombosis

The formation of a blood clot that partially or completely blocks the blood vessel.

Thrombus

A blood clot formed in a blood vessel.

Thrush

A fungal infection (candidiasis) of the mouth, often occurring in infancy, but also in immunocompromised people whose resistance to disease is lowered.

Thymus

A gland active in childhood and located behind the breastbone. It plays a part in defending the body against infection.

Thyroidectomy

Surgical removal of the thyroid.

Thyroid gland

The ductless gland located in the neck. The secretions of the thyroid gland control the rate of metabolism, among other functions.

Thyroxin

The primary hormone secretion of the thyroid gland.

Tibia

The shinbone. The larger (inner) of the two bones of the lower leg.

Tic

Involuntary spasmodic movements or twitching.

Tick

A blood-sucking parasite that is associated with the spread of disease.

Tincture

A medicinal mixture of alcohol and a drug.

Tinea (ringworm)

Fungus infection of the skin, and depending upon the location, the cause of barber's itch, jock itch, scalp ringworm, or ringworm of the foot.

Tinea cruris

Fungal infection of the groin area. Commonly called jock itch.

Tinea pedia (athlete's foot)

A fungal infection of the foot characterized by itching, small sores, and cracks on the skin.

Tinnitus

Ringing, buzzing, or other perceived noises that originate inside the head rather than from outside stimuli.

Tissue

A group of cells or fibers that perform similar functions and together form a body structure.

Tonsillectomy

Surgical removal of the tonsils.

Tonsillitis

Inflammation of the tonsils.

Tonsils

The two masses of lymphoid tissue covered by a mucous membrane that are located one on each side of the back of the throat.

Topical

Local.

Torticollis (wry neck)

A condition in which the (sternocleidomastoid) muscle on one side of the neck contracts and pulls the head into an abnormal position.

Toxemia (blood poisoning)

A condition in which poisonous compounds (toxins) are present in the bloodstream. Toxemia of pregnancy is another term for eclampsia.

Toxic

Poisonous.

Toxic shock syndrome (TSS)

An acute form of blood poisoning caused by the Staphylococcus aureus bacteria. It is associated with the use of superabsorbent tampons during menstruation but has been identified in children and men as well.

Toxin

A poisonous substance produced by bacteria that may have serious effects in humans. Examples include toxic shock syndrome or botulism.

Toxoid

A toxin that has been altered so that it is no longer poisonous but still stimulates antibody production. Used in vaccinations.

Toxoplasmosis

A disease transmitted from animals (especially cats) to humans by parasite-infected feces or by eating undercooked meat containing the parasite. Infection during pregnancy can cause birth defects or fetal death.

Trachea

The windpipe; the tube that extends from the larynx to the bronchi.

Tracheitis

Inflammation of the trachea.

Tracheobronchitis

Inflammation of the trachea and the bronchi.

Tracheotomy

A surgical operation in which an artificial slit is made in the trachea in order to bypass an obstruction and allow air into the lungs.

Trachoma

A contagious virus disease of the eye in which the conjunctiva and other mucous membranes become infected. May lead to blindness.

Traction

Continuous pulling of a body part using weights and pulleys. Used in treatment of dislocations, deformity, and severe muscle spasm.

Tranquilizers

A category of drugs used to relieve anxiety or calm disturbed behavior. "Minor" tranquilizers (such as Valium) are used to alleviate anxiety in stressful situations. "Major" tranquilizers (such as Thorazine) are used to reduce psychotic symptoms.

Transfusion

The injection of fluids (usually blood or its components) into the circulatory system.

Transplantation

The transference of an organ or tissue from one part of the body to another or from one individual to another.

Trauma

Injury to the body or emotional shock.

Tremor

Involuntary quivering or trembling. May have nervous, congenital, or organic origin or may result from certain drugs.

Triceps

The muscle that extends the forearm.

Trichinosis

A disease caused by ingestion of parasites often found in raw or insufficiently cooked pork.

Trichomoniasis

Inflammation, usually of the vagina but also may affect the urethra in males, caused by a protozoan (single-celled) parasite, Trichomonas vaginalis.

Tricuspid valve

The heart valve through which blood passes from the right atrium to the right ventricle.

Trigeminal nerve

The fifth cranial nerve. Its three branches serve the face, the tongue, and the teeth.

Triglycerides

The most common lipid found in fatty tissue. A high level of triglycerides may increase the risk of blood vessel or heart disease.

Truss

A device used to hold a hernia or organ in place.

Trypsin

An enzyme produced in the pancreas to digest proteins.

Tubal ligation (salpingectomy)

Method of sterilization in which the fallopian tubes are tied or cut so that the sperm is unable to meet the ovum.

Tubal pregnancy

The most common form of ectopic pregnancy in which the fertilized egg starts to develop in the Fallopian tubes rather than in the uterus.

Tubercle

1. A nodule on a bone. 2. The lesion characteristic of tuberculosis.

Tuberculin test

A skin test used to detect tuberculosis or tuberculosis sensitivity. An extract of tubercle bacilli is injected into the skin and a positive reaction indicates possible tuberculosis or a previous exposure to the disease.

Tuberculosis

An infectious disease affecting the lungs most often but also other parts of the body. It is caused by the tubercle bacillus and symptoms include cough, chest pains, fatigue, sweating, and weight loss. Commonly referred to as TB.

Tubule

A small tube.

Tularemia

Rabbit fever. A disease of small animals that is spread to humans by direct contact (e.g., handling the meat of an infected animal) or by the bite of a vector, such as a tick or flea. Symptoms include chills, fever, and swollen lymph nodes.

Tumefaction

Swelling.

Tumor

An abnormal growth of tissue similar to normal tissue but without function. May be benign (harmless) or malignant (cancerous).

Tympanic membrane

The eardrum.

Tympanum

The middle ear.

Typhoid fever

A bacterial infection spread through contaminated water, milk, or food, especially shellfish. Symptoms include fever and diarrhea and disease may cause fatal dehydration.

Typhus

A rickettsial disease transmitted by lice to humans. Symptoms include headache, chills, pain, and fever.

Ulcer

An open sore on the skin or in a body cavity. Term commonly refers to intestinal or peptic ulcers, which form in the digestive tract.

Ulcerative colitis

An inflammation of the colon and rectum in which ulcers in the digestive tract cause bloody stool.

Ulna

The larger bone of the forearm.

Ultrasound

Sound waves of very high frequency used for diagnostic purposes. The echoes of the ultrasound are registered with devices that construct pictures showing internal organs.

Umbilical cord

The tube that connects the fetus to the placenta and through which the fetus is nourished and wastes are disposed.

Umbilicus

The navel. The round scar in the middle of the abdomen left by the cutting of the umbilical cord after birth.

Undulant fever (brucellosis, or Malta fever)

A disease transmitted from animals to humans through contaminated, unpasteurized milk products. Symptoms include fatigue, chills, joint pains, and a fever that undulates between near normal and extremely high (104oF).

Urea

The nitrogen-containing waste product of protein breakdown that is excreted as the main component of urine.

Uremia

A condition in which toxic substances remain in the blood due to the failure of the kidneys to filter out and excrete them.

Ureter

One of the two tubes connecting the kidneys to the bladder and through which urine passes (by means of muscle contractions) into the bladder.

Urethra

The tube through which the urine passes from the bladder to the outside. In the female, it is about 11/2 inches long; in the male, it is 8 to 9 inches long.

Urethritis

Inflammation of the urethra.

Uric acid

An acid that is the waste product of metabolism. It is usually excreted in the urine; a buildup of it is characteristic of gout.

Urinalysis

Examination and analysis of the urine for diagnostic purposes.

Urination (micturition)

The discharge of liquid waste through the urethra.

Urine

The amber-colored liquid produced in the kidneys from waste products filtered out of the blood. It is released through the ureters to the bladder, where it is stored temporarily before excretion. The urine is discharged from the bladder through the urethra during urination.

Urogenital

Pertaining to the urinary and genital organs.

Urology

The branch of medical science that deals with disorders of the urinary tract of the female and the urogenital system of the male.

Urticaria (hives)

An allergic reaction in which itchy elevations (wheals or welts) appear on the skin. May be due to a food allergy, drugs, or other substances. Antihistamines may be prescribed in serious or recurring cases, but most hives disappear in a few days with no treatment.

Uterus (womb)

The hollow, pear-shaped muscular organ where the fertilized ovum develops during pregnancy. It normally weighs about 2 ounces but enlarges to 30 ounces in pregnancy.

Uvea

The pigmented parts of the eye.

Uvula

The small tag of tissue that hangs from the center of the soft palate at the back of the throat.

Vaccination

Inoculation of an antigenic substance in order to stimulate immunity to disease.

Vaccine

Dead or weakened microorganisms that prevent disease by stimulating artificial immunity.

Vaccinia

Cowpox.

Vagina

The muscular canal lined with mucous membrane that extends from the vulva to the uterus. Sometimes referred to as the birth canal.

Vaginismus

Painful contractions of the muscles of the vagina; often responsible for painful intercourse.

Vaginitis

Inflammation of the vagina, accompanied by discharge and discomfort.

Vagus

The 10th cranial nerve that extends from the brain to serve the stomach, intestines, esophagus, larynx, lungs, and heart.

Varicella

Chickenpox.

Varicocele

Varicose or swollen veins in the spermatic cord.

Varicose veins

Abnormally swollen, dilated veins in which the valves are weakened and therefore allow the backflow of blood. Areas most commonly affected are the lower legs and the rectum. See also Hemorrhoids.

Variola

Smallpox.

Vas deferens

The duct of the testes through which the spermatozoa must pass in ejaculation.

Vascular

Pertaining to, or supplied with, vessels, usually blood vessels.

Vasectomy

A method of sterilization of the male. The passageway of the vas deferens is cut off so that the spermatozoa cannot enter the semen.

Vasoconstrictor

Any agent that causes the blood vessels to narrow or to contract.

Vasodilator

Any agent that causes the blood vessels to widen or enlarge.

Vasomotor

Having the ability to contract or enlarge the blood vessels.

Vector

An animal, insect, or person that carries disease.

Vein

The vessels that carry deoxygenated blood from all parts of the body back to the heart.

Venereal diseases

Diseases transmitted through sexual contact.

Venesection (bloodletting)

Cutting a vein for the withdrawal of blood.

Venipuncture

Puncturing a vein for the withdrawal of blood.

Venous

Pertaining to the veins.

Ventral

Pertaining to the front of the body; the abdomen.

Ventricle

A small cavity, especially the two lower muscular chambers of the heart and the four cavities of the brain.

Venule

A small vein that serves as a link between the arterial and venous systems.

Verruca

A wart.

Vertebra

One of the 33 flat, roundish bones that make up the spinal column.

Vertigo

Dizziness.

Vesicle

A small sac or bladder.

Viable

Capable of survival.

Vibrios

Hooklike bacteria.

Villus

A microscopic finger-shaped projection such as those found in the mucous lining of the stomach walls.

Viral

Pertaining to a virus.

Virulent

Poisonous; disease-producing.

Virus

A submicroscopic organism that causes disease and is capable of reproduction only within the living cells of another organism (such as a plant, animal, or human). Viruses cause many diseases of humans, ranging from mild ailments (such as the common cold) to serious, even fatal, diseases.

Viscera

The internal organs (viscus -- an internal organ).

See

Rhodopsin.

Vitreous humor

The jellylike substance that is found between the lens and the retina and that supports the interior parts of the eye.

Vocal cords

Two ligaments in the larynx, the vibrations of which produce the sounds of the human voice.

Volvulus

A twist or knot in the intestine that blocks passage.

Vomit

Ejection of matter from the stomach through the mouth.

Vulva

The external genitalia of the female, including the clitoris and vaginal lips.

Vulvovaginitis

Bacteria-caused inflammation of the vulva and the vagina.

Walleye

An eye condition in which the cornea is whitish and opaque instead of clear; term also used to describe a form of divergent strabismus (crossed eyes) in which the images are slanted in different directions instead of merging into one.

Wart

Small, harmless growths on the skin caused by a virus.

Wasserman test

A blood test used to detect syphilis.

Wen

A sebaceous cyst caused by the obstruction of an oil gland of the skin.

Wheal

A temporary skin elevation, usually a result of an allergic reaction.

See

Leukocytes.

Widal test

A blood test used to detect typhoid fever.

See

Trachea.

See

Uterus.

Xanthoma

An accumulation or nodule of cholesterol that forms under the skin and appears as an elevated yellow patch.

Xeroderm

Dry skin.

Xerophthalmia

A dryness of the membranes of the eyelids and eye, associated with vitamin A deficiency.

Xerosis

Abnormal dryness.

Xiphoid

The sword-shaped piece of cartilage at the lower edge of the breastbone.

X-rays

Electromagnetic radiation waves of very short length that are capable of penetrating some substances and producing shadow pictures showing structures of differing densities.

Yaws (frambesia)

A tropical disease very similar to syphilis and caused by a spirochete resembling syphilis organisms.

Yellow fever

An acute disease caused by a virus spread by insect bites. Usually seen in South America and Africa.

Zoonoses

Any disease transmitted by an animal to humans.

See

Herpes zoster; Shingles.

Zygote

The fertilized egg before division.