Medical Glossary

Medical Glossary

Medical Glossary


abrade: To chafe; to roughen or remove by friction.

acetabulum: Rounded cavity on the outer surface of the hip bone that receives the head of the femur.

acidosis: Higher-than-normal acidity in body fluids due to the accumulation of acids or the excessive loss of bicarbonate.

adenoma: Tumor of a gland or cancerous growth in glandular epithelial tissue.

adjuvant analgesic: Any drug whose primary purpose is not generally used or prescribed for pain but can also serve as an analgesic for some pain conditions.

agnosia: Loss of ability to understand or interpret auditory, visual, or other forms of sensory information even though the respective sensory organs are functioning properly.

agraphia: Loss of ability to convert thought into writing.

albumin: One of a group of simple plasma proteins in humans that can act as a source for rapid replacement of tissue proteins.

alexia: Loss of ability to understand the written language.

alkalosis: Excessive alkalinity of body fluids due to accumulation of alkalines or reduction of acids.

allogeneic: Belonging to the same species but having a different genetic constitution.

alogia: Inability to speak owing to a mental condition or a symptom of dementia.

alopecia: Absence or loss of hair, especially on the head.

alveoli (pulmonary): The microscopic air sacs in the lungs through whose walls the exchange of carbon dioxide and oxygen occurs.

amblyopia: Unilateral reduction in visual acuity in which there is no apparent pathological condition of the eye.

amenorrhea: Absence of menstruation.

amino acid: Any one of a large group of organic compounds constituting the primary building blocks of proteins.

analgesic: Drug or other agent used to relieve pain.

anaphylaxis: Allergic reaction of the body to a foreign body or other substance. Sometimes used to refer exclusively to a sudden, unusually severe, and possibly life-threatening allergic reaction.

anaplasia: Loss of structural differentiation, as seen in malignant neoplasms.

anastomosis: Surgical, traumatic, or pathological formation of a connection between two normally separate tubular structures or organs in the body.

aneurysm: Abnormal, saclike bulge in the wall of an artery, a vein, or the heart.

ankylosis: Immobility of a joint.

anorexia: Loss of appetite for foods.

anoxia: Absence of oxygen.

antibody: Protein substance produced by the body’s immune system in response to and interacting with a specific antigen.

anticholinergic (drug): Drug or agent that inhibits the action of the neurotransmitter chemical acetylcholine, blocking parasympathetic nerve impulses, with consequent reduction of smoothmuscle contractions and various bodily secretions.

antiemetic: Drug or other agent used to prevent or stop vomiting.

antigen: Any substance that, when introduced into the body, causes the production of a specific antibody by the immune system.

antipruritic: Agent that prevents or relieves itching.

antipyretic: Drug or agent that reduces fever.

anuria: Absence of urine formation.

aphasia: Loss or impairment of the ability to communicate through speech, writing, or signs due to dysfunction of brain centers.

apnea: Temporary cessation in breathing.

arrhythmia (cardiac): Irregularities in the force or rhythm of heart action caused by disturbances in the discharge of cardiac impulses from the heart’s sinoatrial node or their transmission through the heart’s conductile tissue.

arthralgia: Pain in a joint.

ascites: Abnormal accumulation of fluid in the peritoneal cavity.

atelectasis: In a neonate, the failure of the lung to completely expand at birth; generally, a collapsed lung. The collapse may be complete or partial.

atropine: Anticholinergic agent that counteracts effects of parasympathetic stimulation.

auscultation: Listening to sounds produced by the internal organs or other body parts for diagnostic purposes.

autologous: Originating within an individual, especially a factor present in tissues or fluids.

avolition: Lack of motivation for work or other goal-oriented activity.

axon: A process of a neuron that conducts impulses away from the cell body.

azotemia: Presence of urea in the blood.


bacteremia: Bacteria in the blood.

bilirubin: Orange- to yellow-colored compound in the blood plasma, produced by the breakdown of hemoglobin following the normal or pathological destruction of red blood cells. It is collected by the liver to produce bile.

bilirubinuria: Presence of bilirubin in the urine. May be indicative of a liver or blood disorder.

biotin: Component of the vitamin B complex essential for the metabolism of fat and carbohydrates.

blast: Precursor of the final, mature form of a cell.

bleb: Irregularly shaped elevation of the epidermis. A blister.

blepharoptosis: Drooping of the upper eyelid.

bradycardia: Abnormally slow heartbeat, generally characterized by a pulse rate below 60 beats per minute.

bradykinesia: Extreme slowness of movement.

bronchiole: One of the many smaller passages conveying air with the lung.

bruit: Abnormal noise of venous or arterial origin heard during auscultation.

bulla (pl., bullae): Large (generally greater than 0.5 cm) fluid-filled blister.


cachexia: Marked wasting away of the body, usually as a consequence of chronic disease.

calyx (pl., calyces): Cuplike extension of the renal pelvis that encloses the papilla of a renal pyramid; urine from the papillary duct empties into it.

carcinogen: Any substance or agent that can produce cancer.

carcinoma in situ: Malignant cell changes in the epithelial tissue that do not extend beyond the basement membrane; “cancer in place.”

cardiac tamponade: A life-threatening condition in which elevated pressures within the pericardium impair the filling of the heart during diastole.

cardiomegaly: Increase in the volume of the heart or the size of the heart muscle tissue.

cardioversion: Restoration of normal sinus rhythm by chemical or electrical means.

cellulitis: Inflammation of cellular or connective tissue.

cerebrospinal fluid: Clear fluid that bathes the ventricles of the brain and the central cavity of the spinal cord.

cervicitis: Inflammation of the cervix.

chancre: Firm, red, ulcerated sore. A chancre is the primary indication of syphilis; it occurs at the point of entry of the infection.

Cheyne-Stokes respiration: Breathing pattern disturbance characterized by a period of deep, rapid respirations followed by a period of shallow respirations or no respirations at all. The cycle rhythmically repeats every 45 seconds to 3 minutes.

Chiari malformation: (Also called Arnold-Chiari deformity.) A condition in which the inferior poles of the cerebellar hemispheres and the medulla protrude through the foramen magnum into the spinal canal. It is one of the causes of hydrocephalus and is usually accompanied by spina bifida cystica and meningomyelocele.

chromosome: In human cells, a linear structure in the nucleus composed of DNA and proteins and bearing part of the genetic information of the cell. Each human cell (except for egg or sperm cells) has 46 chromosomes, occurring in 23 pairs.

chyme: Nearly liquid mixture, composed of partially digested food and gastric secretions, that is found in the stomach and duodenum during digestion of a meal.

claudication: Lameness; limping.

clubbing: Condition characterized by bulbous swelling of the tips of the fingers and toes.

colectomy: Surgical removal of all or a portion of the colon.

comedo: Plug of dried, discolored fatty matter clogging a pore of the skin; commonly called a blackhead.

conization: Surgical removal of a cone of tissue, such as excision of cervical tissue for microscopic examination.

conjunctiva: Mucous membrane lining the eyelids.

contracture: Permanent shortening or contraction of a muscle, often producing physical distortion or deformity.

cordotomy: Surgical division of one or more of the lateral nerve pathways emerging from the spinal cord to relieve pain.

coryza: Common cold. An acute inflammation of the nasal mucous membrane accompanied by profuse nasal discharge.

craniotomy: Surgical incision through the cranium.

creatinine: Nitrogen-based compound formed in muscle tissue, passed into the bloodstream, and excreted in the urine. Elevated levels of creatinine in the blood may indicate a kidney disorder.

crepitation: Crackling sound, such as that produced by the grating of ends of a broken bone.

cryoablation: A procedure to remove tissue through the use of extreme cold.

cyanosis: Bluish discoloration of the skin and mucous membranes due to an increased proportion of unoxygenated hemoglobin in the blood.

cystectomy: Removal of a cyst. Excision of the cystic duct and the gallbladder. Excision of all or part of the urinary bladder.


debridement: Removal of dead or damaged tissue or other matter, especially from a wound.

decompensate: Inability to maintain defense mechanisms in response to stress, resulting in personality disturbance or psychological imbalance.

delusion: A false belief brought about without appropriate external stimulation and inconsistent with one’s own knowledge and experience.

dendrites: The branched, tapering cell processes of the neurons.

deoxyribonucleic acid (DNA): An acid containing the genetic instructions used in the development and functioning of all living organisms.

diaphoresis: Sweating, especially when profuse or medically induced.

diastole: Period of cardiac muscle relaxation alternating with systole or contraction.

diastolic pressure: Lowest arterial pressure reached during any ventricular cycle.

digoxin: The most frequently prescribed digitalis glycoside to treat clients with congestive heart failure, atrial fibrillation, atrial flutter, and supraventricular tachycardia.

dilatation: Expansion or enlargement of an organ or vessel.

dilation and curettage (D&C): The uterine cervical canal is expanded (dilated) to allow scraping (curettage) of the surface lining of the uterus.

diplopia: Double vision.

diuretic: Drug or agent that promotes the secretion of urine.

ductus arteriosus: Connection between the aorta and the pulmonary artery in the fetus; it allows most of the blood pumped by the left ventricle to bypass the lungs (which do not function in the fetus) and enter the systemic circulation. In some infants, the connection persists after birth; the condition is known as patent ductus arteriosus.

dysphagia: Difficulty in swallowing or inability to swallow.

dysphasia: Impairment of speech resulting from a brain lesion.

dysplasia: Alteration in size, shape, and organization of mature cells.

dyspnea: Labored or difficult breathing, generally indicating an insufficient amount of oxygen in the blood.

dystonia: Prolonged muscular contractions that may cause twisting (torsion) of body parts, repetitive movements and increased muscular tone.

dysuria: Difficult or painful urination, symptomatic of numerous conditions.


echolalia: Involuntarily repeating words spoken by others.

edema: Excessive accumulation of fluid in bodily tissues. May be localized or general.

effacement: Dilation of the cervix.

effusion: Seeping of fluid into a body cavity or part.

electrodesiccation: Method of electrosurgery in which tissue is destroyed by dehydration with a probe generating a series of short, high-frequency electric sparks.

electrolytes: Ionized salts present in blood and tissue fluids and within cells. They are involved in all metabolic processes and are essential to the normal functioning of all cells.

embolism: Obstruction of a blood vessel by foreign substances or a blood clot.

embolus: Clot or undissolved mass carried through the circulatory vessels by the blood or lymph flow. An embolus may be a blood clot, piece of tissue, fat globule, or air bubble. (Compare with thrombus.)

enanthems: Mucous membrane eruption.

en bloc: To remove as one piece (in surgery).

endoplasmic reticulum: A network of sacs that manufactures, processes, and transports chemical compounds for use inside and outside of the cell; responsible for the production of the protein and lipid components of most of the cell’s organelles

endorphin: One of a group of naturally occurring substances, produced by the central nervous system, that reduce the perception of pain. (See enkephalin.)

enkephalin: Substance produced in the brain that acts opiate-like and produces analgesia. (See endorphin.)

enteropathy: Any disease of the intestine.

epididymis (pl., epididymides): A small, oblong organ resting on and beside the posterior surface of a testis, consisting of a convoluted tube 13 to 20 ft long, enveloped in the tunica vaginalis, ending in the ductus deferens.

epigastric: Pertaining to the epigastrium, the region of the abdomen over the pit of the stomach.

epistaxis: Hemorrhage from the nose; a nosebleed.

epithelial: Pertaining to the layer of cells forming the outer surface of the body, the lining of the body cavities, and principal tubes and passageways.

erythema (erythematous): Diffused redness of the skin due to dilation of the superficial capillaries.

exanthems: Any eruption or rash of the skin (not the mucous membrane). Term often used to describe childhood or infectious rashes.

excoriation: Abrasion of the skin or of the surface of any organ by trauma, chemical agents, burns, or other causes.

exfoliative cytology: Microscopic examination of cells that have been shed from or scaled off the surface epithelium. Performed for diagnostic purposes.

exocrine: Pertaining to glands that release their secretions into the digestive tract or to the outer surface of the body.

exophthalmos: Abnormal protrusion of the eyeball.

exudate: Fluid discharged through vessel walls and collecting in adjacent tissue. It has a high content of protein and cellular debris. (Compare with transudate.)


fecalith: Hard, solid, intestinal mass formed around a core of fecal material.

fibrillation (ventricular): Cardiac arrhythmia characterized by the rapid, incomplete, and uncoordinated contractions of the muscle fibers of ventricles of the heart. Can lead to cardiac arrest. (See arrhythmia.)

fibrinogen: A protein synthesized by the liver and present in blood plasma that is converted into fibrin through the action of thrombin in the presence of calcium ions.

fissure: Groove, natural division, cleft, slit, or deep furrow in organs; an ulcer or cracklike sore.

fistula: Abnormal tubelike passage from a normal cavity or tube to a free surface or to another cavity.

flat affect: Lacking stimulating characteristics.

folate: Salt or ester of folic acid.

follicle-stimulating hormone (FSH): Secretion of the pituitary gland that stimulates the growth and maturation of the Graafian follicles in the ovary or the production of sperm in the testes.

fontanel: Incompletely ossified space or soft spot between the cranial bones of the skull of a fetus or infant.

foramen magnum: Opening in the occipital bone through which the spinal cord passes from the brain.


gamete intrafallopian transfer (GIFT): After ovulation is induced, ova are retrieved via laparoscopy and are transferred along with sperm to the fallopian tubes.

gamma globulin: Class of proteins formed in the blood that function as antibodies. Ability to resist infection is related to the concentration of these proteins.

ganglion: Mass of nervelike cell bodies lying outside the brain and spinal cord.

gangrene: Death of masses of body tissue followed by bacterial invasion and subsequent decay; usually, but not exclusively, associated with the loss or interruption of blood supply to a tissue area.

genistein: Soy estrogen-like compound that has been found to inhibit the activity of enzymes involved in the control of cell proliferation.

genotype: Description of the combination of genes of an individual, either with respect to a single trait or with respect to a larger set of traits. (Contrast with phenotype.)

gliadin: Water-soluble protein present in the gluten of wheat. The sticky mass that results when wheat flour and water are mixed is due to gliadin.

globulin: One of the plasma proteins to control osmotic pressure within capillaries.

glycogen: Molecule that is the principal storage form of glucose in human cells.

glycosuria: Presence of sugar, particularly glucose, in the urine.

goitrogens: Substances that cause goiters. These occur in nature in certain foods, including turnips, rutabagas, and cabbage.

gonorrheal ophthalmia neonatorum: In the newborn, the severe, hyperacute inflammation of the membrane lining the inner surface of the eyelids and covering the white of the eye. Caused by infection with gonococci.


hallucination: False perception having no relation to reality and not accounted for by exterior stimulus.

hematemesis: Vomiting blood.

hematochezia: Passage of bright red blood in the stool.

hematopoietic: Related to the formation of red blood cells.

hematuria: Blood in the urine.

hemiparesis: Paralysis affecting only one side of the body.

hemoglobin: Oxygen-carrying pigment in red blood cells.

hemolysis: Rupturing of red blood cells with the resulting release of hemoglobin into the plasma.

hemoptysis: Coughing and spitting up of blood due to bleeding in any portion of the respiratory tract.

hemostasis: An arrest of bleeding or of circulation.

hepatomegaly: Enlargement of the liver.

heterozygous: Possessing different genes from each parent for a particular trait.

hirsutism: Condition marked by excessive growth of hair in unusual places, especially in women.

homeostasis: Tendency of the body systems to maintain stability even though they are exposed to continually changing outside forces.

homozygous: Possessing identical genes from each parent for a particular trait.

hydronephrosis: Swelling of the renal pelvis of the kidney with urine due to obstructed outflow.

hydroureter: Distention of the ureter with fluid due to obstructed outflow.

hyperchlorhydria: Excessive amount of hydrochloric acid in the stomach.

hyperglycemia: Abnormally high levels of glucose in the blood.

hyperkalemia: Excessive amount of potassium in the blood, usually caused by inadequate excretion of potassium or the shift of potassium from tissues.

hyperlipemia: Excess levels of fatlike substances called lipids in the blood.

hyperparathyroidism: Oversecretion of parathyroid hormone by the parathyroid glands.

hyperplasia: Overproliferation of normal cells within a normal tissue structure.

hypersomnia: Excessive daytime sleepiness.

hypertension: Persistently high arterial blood pressure.

hypertrophy: Increase in size or volume of an organ or other body structure that is produced entirely by an increase in the size of existing cells, not by an increase in the number of cells.

hypoalbuminemia: Abnormally low levels of a protein called albumin in the blood plasma.

hypoglycemia: Abnormally low levels of glucose in the blood.

hypokalemia: Extreme potassium depletion in the circulating blood, commonly manifested by episodes of muscular weakness or paralysis and tetany.

hypophysectomy: Removal of the pituitary gland.

hypovolemic shock: Condition of severe physiologic distress caused by a decrease in the circulating blood volume so large that the body’s metabolic needs cannot be met.

hypoxemia: Decreased oxygen in arterial blood.

hypoxia: Decreased concentration of oxygen in the inspired air and body tissues.

hysterosalpingography: Use of x-rays to visualize the uterus and fallopian tubes.


iatrogenic: Caused by treatment; for instance, an infection caused by a failure of surgical antiseptic precautions.

idiopathic: Of unknown cause.

ileostomy: Surgically created opening in the lower small intestine (ileum), brought to the abdominal surface for the purpose of evacuating feces. May be temporary or permanent.

incontinence: Inability to control the passage of urine, semen, or feces due to one or more physiological or psychological conditions.

induration: Area of hardened tissue; the process of hardening.

in situ: In place. (See carcinoma in situ.)

intrathecal: Within the spinal canal or a sheath.

intromission: Insertion of the penis into the vagina.

in vitro fertilization (IVF): Fertilization that occurs in glass or a test tube.

ischemia: Temporary deficiency of blood in a body part due to a constriction or obstruction of a blood vessel.


jaundice: Condition characterized by a yellowish discoloration of the skin, whites of the eyes, and bodily fluids resulting from the accumulation of bilirubin in the blood. Caused by any of several disease processes in which the normal production and secretion of bile are disrupted.


keratin: Hard, fibrous protein that is the primary constituent of hair and nails.

keratolytic: Agent used to loosen and remove the outer layer of the epidermis.

ketoacidosis: Abnormally high concentrations in the blood or tissues of organic compounds called

ketone bodies: beta-hydroxybutyric acid, acetoacidic acid, and acetone. It is sometimes called ketosis. The condition is frequently associated with diabetes mellitus.

ketone: A substance containing the carbonyl group attached to two carbon atoms. Acetone is an example of a simple ketone.

Koplik spots: Small red spots with bluish white centers on the oral mucosa, particularly in the region opposite the molars. A diagnostic sign in measles.

kyphoscoliosis: Abnormal backward and lateral curvature of the spine.


lacteals: Lymphatic capillaries in a villus of the small intestine that absorb fatty acids and other fat-soluble products of digestion.

lassitude: State of exhaustion or profound listlessness.

leiomyoma: Tumor of smooth-muscle tissue.

lesion: Any discontinuity or disruption of tissue caused by disease or trauma.

leukocytosis: Temporary increase in the number of white cells in the blood, typically, but not exclusively, caused by the presence of infection.

leukopenia: Abnormal decrease in the number of circulating white blood cells.

ligation: Process of tying off blood vessels or constricting other body tissues for therapeutic purposes.

lipiduria: Lipids in the urine.

lochia: Postpartum discharge of blood, mucus, and tissue from the uterus.

lumbar: Pertaining to the part of the back between the thorax and pelvis.

lumen: Space within an artery, vein, intestine, or other tubular structure.

luxation: Displacement of organs or articular surfaces; complete dislocation of a joint.

lymphadenopathy: Disease of the lymph nodes, usually manifested as swelling of the nodes.

lymphangitis: Inflammation of lymph vessels.

lymphocytopenia: Presence of abnormally small numbers of lymphocytes in the circulating blood.


macrophage: Any of the class of cells within the body tissues having the ability to engulf particular substances and microorganisms.

macula: Small, colored spot or thickening.

malaise: Generalized feeling of illness, discomfort, or depression indicative of some underlying disease or disorder.

maxillomandibular advancement: Surgical treatment for obstructive sleep apnea; both the upper jaw (maxilla) and lower jaw (mandible) are moved forward to enlarge the airway.

McBurney point: Point of special abdominal tenderness indicating acute appendicitis. It lies over and corresponds with the normal position of the appendix.

meconium: First feces of a newborn infant, made of salts, amniotic fluid, mucus, bile, and epithelial cells. The substance is greenish black, almost odorless, and tarry.

megakaryocyte: Large bone marrow cell with large or multiple nuclei. It gives rise to blood platelets.

meiosis: Process of two successive cell divisions, producing cells, egg or sperm, that contain half the number of chromosomes in somatic cells. When fertilization occurs, the nuclei of the sperm and ovum fuse and produce a zygote with the full chromosome complement.

melanin: Dark pigment that gives color to skin and hair.

menarche: Initial menstrual cycle, marking the onset of fertility.

meninges: Three membranes covering the brain and spinal cord.

menorrhagia: Excessive menstrual flow in duration or quantity, or both.

mesothelioma: A malignant tumor derived from the mesothelial cells of the pleura, peritoneum, or pericardium. It is found most often in smokers or persons with a history of exposure to asbestos.

metastasis (metastasize): Movement of bacteria or body cells, especially cancer cells, from one part of the body to the other, typically by way of the circulatory system.

metrorrhea: Abnormal uterine discharge.

microcephaly: Abnormally small head.

micturition: Urination.

mitochondria: Microscopic cell organelle that contains enzymes for cell respiration.

mitral regurgitation: Backward flow of blood through the mitral valve of the heart.

Mohs micrographic surgery: A method of excising skin tumors a layer at a time until entire tumor is removed. Developed by Frederic Edward Mohs, U.S. surgeon.

monoamine oxidase inhibitors (MAOIs): One member of a group of drugs that can be used to treat depression.

mutism: Persistent inhibition of speech seen in some severe forms of mental illness.

myalgia: Muscle pain or tenderness.

myringotomy: Surgical incision of the tympanic membrane (eardrum).


nephrectomy: Removal of a kidney.

neuromodulator: Alteration in function or status in response to a stimulus of the nerve.

neuropathic pain: Discomfort that originates in peripheral nerves or the central nervous system rather than from damage in organs or tissues.

neuropeptides: Brain messengers responsible for mood, energy levels, pain and pleasure reception, body weight, and ability to solve problems; they also form memories and regulate the immune system.

neurotomy: Division or dissection of a nerve.

neurotransmitter: Substance produced and released by one neuron that travels across a synapse, exciting or inhibiting the next neuron in the neural pathway.

nevus (pl., nevi): Birthmark or mole; congenital discoloration of the skin due to abnormal pigmentation or vascular tumor.

nociceptive pain: Pain from tissue damage; may be sharp, dull, or aching but does not follow a nerve distribution.

nocturia: Excessive urination at night.

nonopioids: Nonopium drugs, formerly referred to as nonnarcotic; include such drugs as acetaminophen and nonsteroidal antiinflammatory drugs.

nosocomial: Occurring in a health-care setting.

nosocomial infection: An infection acquired in a hospital, nursing home, or other health-care setting.

nuchal rigidity: Stiff neck.

nystagmus: Rhythmic, involuntary movement of the eyeball.


occult blood: Minute quantities of blood in feces, urine, and gastric fluid, detectable only by microscopic examination or chemical test.

oliguria: Reduced urine secretion.

oogenesis: The creation of the mature human ovum.

opioids: Any synthetic or natural narcotic that relieves pain, with morphinelike activity.

orchidectomy: Surgical removal of a testis.

orchitis: Inflammation of the testes.

orthopnea: Respiratory condition in which there is discomfort in breathing in any but erect standing or sitting positions.

Ortolani maneuver: A test to detect congenital subluxation or dislocation of the hip.

Ortolani sign: The “clunk” felt when an examiner abducts (draws away from the body) and lifts the femurs of a supine infant. The clunk indicates a partial or an incomplete displacement of the hip.

osteomalacia: Disease caused by vitamin D deficiency in adults that causes soft, flexible, brittle, deformed bones.


palliative: Treatment provided to relieve the symptoms of a disease rather than to effect a cure.

pallor: Lack of color; paleness, as of the skin.

panhysterosalpingo-oophorectomy: Surgical removal of the entire uterus, including the cervix, ovaries, and fallopian tubes.

Papanicolaou test (smear): Diagnostic test for the early detection of cancer cells. Commonly called Pap test, Pap smear.

papule: Red, raised area of the skin, generally small and solid.

parasympathetic: Referring to a portion of the automatic (involuntary) nervous system. Activity of the parasympathetic nerves produces affects such as constriction of the pupil of the eye and slowed heart rate.

parenteral: Taken into the body or administered by some route other than the digestive system, for example, intravenous, subcutaneous, intramuscular, or mucosal.

paresthesia: Sensation of numbness, prickling, or tingling.

parturition: Act of giving birth.

pathogenic: Capable of causing disease.

percussion: Diagnostic technique in which various body surfaces are tapped; the resulting sounds indicate the size, position, and general condition of underlying organs or structures.

pericardiocentesis: Surgical puncture of the membranous sac surrounding the heart to draw out fluid.

pericardium: Membranous fibroserous sac enclosing the heart; the outer layer.

peristalsis: Involuntary wavelike contraction occurring along the walls of the hollow tubes of the body, especially the esophagus, stomach, and intestines.

petechia (pl., petechiae): A small, reddish or purplish pinpoint spot on a body surface, such as the skin or mucous membranes, caused by a minute hemorrhage.

pH: Degree of acidity or alkalinity of a solution, expressed in numbers from 0 to 14. Maximum acidity is pH 0 and maximum alkalinity is pH 14. A pH of 7 is neutral.

phacoemulsification: Ultrasonic device that disintegrates cataracts so they can be aspirated and removed.

phagocytosis: Ingestion and digestion of bacteria, other cells, and particles by a class of cells called phagocytes.

phenotype: Observable physical characteristics of an individual, determined by the combined influences of the individual’s genetic makeup and the effects of environmental factors. (Contrast with genotype.)

photophobia: Unusual intolerance of light.

plaque: Solid, elevated patch of skin. Often formed from the combination of numerous, closely spaced papules.

pleurectomy: Surgical excision of a portion of the pleura.

plication: Surgical procedure in which folds in the wall of an organ are stitched together to reduce its size.

polycythemia vera: Chronic, life-shortening disorder of the bone marrow, involving the tissue producing blood cells. It is primarily characterized by abnormally high numbers of circulating red blood cells.

polydipsia: Excessive thirst.

polymorphonuclear leukocyte: White blood cell that possesses a nucleus composed of 200 or more lobes or parts.

polyphagia: Eating abnormally large amounts of food.

polyposis: Formation of numerous small growths or masses on a mucous membrane surface.

polysubstance dependence: Condition occurring when individuals exhibit behaviors associated with the inability to control the use of many different drugs or substances.

polyuria: Excessive formation and discharge of urine.

postural drainage: Therapeutic technique in which a client is directed to assume a variety of positions that facilitate the drainage of secretions in the lobes of the lungs or the bronchial passages.

prebiotics: A nutrient that stimulates the growth of bacteria living in the large intestine.

prenatal: Before birth.

primigravida: Woman during her first pregnancy.

probiotics: Substance that has a healthpromoting effect on living cells.

prostaglandins: Class of chemically related fatty acids present in many body tissues and having the ability to stimulate smooth-muscle contractions, lower blood pressure, and regulate or influence many other body functions.

proteinuria: An excess of serum proteins in the urine.

prothrombin: A plasma protein coagulation factor synthesized by the liver that is converted to thrombin by prothrombinase and thrombokinase in the presence of calcium ions; sometimes referred to as coagulation factor.

pruritus: Severe itching.

pulmonary infarction: Death of a localized area of lung tissue resulting from an interruption of blood flow to that area. Generally caused by a pulmonary embolism.

purulent (discharge): Containing pus.

pustule: Small, raised area of the skin filled with pus or lymph.

pylorus (pyloric sphincter): Lower opening of the stomach leading into the duodenum. The pylorus is closed most of the time by the pyloric sphincter, a ring of muscles that opens at intervals to allow the flow of chyme into the duodenum.

pyoderma: Any acute, pus-causing, inflammatory skin disease.

pyuria: Pus in the urine.


radiofrequency catheter ablation: Destruction of electrical conduction pathways in the heart with an intracardiac catheter that removes the abnormal conducting tissue.

radioisotope: Radioactive form of an element. Some are commonly used for diagnostic or therapeutic purposes.

Raynaud phenomenon: Intermittent interruptions of blood supply to the fingers, toes, and sometimes the ears, marked by severe pallor of these parts and accompanied by numbness, tingling, or severe pain.

Reed-Sternberg cells: Giant connective tissue cells with one or two large nuclei that are characteristic of Hodgkin disease.

reflux: Flowing back or return flow of fluid or other matter.

resection: Excision.

reticulocyte: Immature form of red blood cell, normally comprising about 1% of circulating red blood cells.

retinopathy: Any disease of the retina of the eye.

rhinitis: Inflammation of the nasal mucous membranes.

rhinophyma: Nodular swelling and congestion of the nose associated with acne rosacea.

rhonchus (pl., rhonchi): Rale or rattling in the throat, especially when it resembles snoring.

ribosomes: Microscopic cell organelles that produce proteins for cells.


sarcomas: A cancer arising from mesenchymal tissue, such as muscle or bone, which may affect the bones, bladder, kidneys, liver, lungs, parotids, and spleen.

sclerotherapy: Injecting irritating chemicals into vascular spaces or body cavities to harden, fill, or destroy them.

scotomata: Temporary, islandlike, blind gaps in the visual field.

seborrhea: Functional disease of the sebaceous glands marked by an increase in the amount, and often an alteration of the quality, of the sebaceous secretion.

septic: Pertaining to disease-causing organisms or their toxins.

septum: Any wall between two cavities; for example, the atrial septum divides the right and left atria of the heart.

sequela: Condition that is the result of a disease.

seroconversion: Development of detectable specific antibodies to a disease-causing organism or vaccine.

serotonin: A chemical found in platelets, gastrointestinal mucosa, mast cells, and the central nervous system; its action on cellular receptors plays a role in intestinal motility, nausea and vomiting, sleep-wake cycles, obsessive-compulsive disorder, depression, and eating.

serous: Pertaining to serum.

somatic: Pertaining to sensation perceived as originating from superficial or muscular structures of the body rather than sensations seeming to come from the internal organs.

spermatogenesis: Process of creating a mature human sperm cell.

spirochete: Member of an order of microorganisms that have a slender, spiral shape.

sputum: Substance expelled by coughing or clearing the throat.

stapedectomy: Excision of the stapes in the ear in order to improve hearing, especially in cases of otosclerosis. The stapes is replaced by a prosthesis.

stenosis: Abnormal constriction or narrowing in an opening or passageway of an organ or body part.

stratum corneum: Outermost or horny layer of the epidermis.

stridor: Harsh, high-pitched sound during respiration due to obstruction of air passages.

stupor: Condition of unconsciousness or lethargy.

suppurative: Pus producing.

syncope: Transient loss of consciousness due to inadequate blood flow to the brain.

syndrome: A group of symptoms or signs linked by a common pathological history.

syngeneic: Descriptive of individuals or cells without detectable tissue incompatibility.

systole: Contraction of the chambers of the heart; the myocardial fibers shorten, making the chamber smaller and forcing out blood.

systolic pressure: Period of maximum arterial blood pressure. (Compare with diastolic pressure.)


tachycardia: Abnormally rapid heart beat, generally defined as exceeding 100 beats per minute.

tachypnea: Abnormal, very rapid breathing.

teratogen: Anything that adversely affects normal cellular development in the embryo or fetus. It may be certain chemicals, some therapeutic and illicit drugs, radiation, and intrauterine viral infections.

teratoma: Tumor composed of a number of different tissue types, none of which is normally found in the area of occurrence. Teratomas usually occur in the testes or ovaries.

tetany: Nervous condition characterized by sharp, painful, periodic muscle contractions, particularly those of the extremities.

thoracentesis: Surgical puncture of the chest wall to remove fluid from either of the pleural cavities.

thoracotomy: Surgical incision in the wall of the chest.

thready pulse: Fine, barely perceptible pulse.

thrombocytopenia: Condition in which there is an abnormally small number of platelets in circulating blood.

thrombocytosis: A condition pertaining to high platelet count in the blood.

thromboendarterectomy: Surgical removal of a thrombus together with a portion of the inner lining from an artery.

thrombus: Blood clot formed along the wall of a blood vessel or in a cavity of the heart. It may be of sufficient size to obstruct blood flow; or all, or a portion, of it may break off to become an embolus. (See embolus.)

Tinel sign: A cutaneous tingling sensation produced by pressing the nerve trunk that has been damaged or is regenerating following trauma; named for Jules Tinel, French neurologist.

tinnitus: Ringing, buzzing, tinkling, or hissing sound in the ear.

tolerance: Acquired resistance to the effects of a drug.

tonometer: Instrument to measure intraocular pressure.

tophus (pl., tophi): Calculus (stone) or mineral deposit in bone or tissue.

toxemia: Condition in which poisonous products of body cells at a local source of infection or derived from the growth of microorganisms are spread throughout the body in the blood.

transillumination: Visual inspection of a body structure or organ by passing a light through its walls.

transsphenoidal: Through or across the sphenoid bone.

transudate: Fluid discharged through a membrane or vessel wall. In contrast to an exudate, a transudate has a low content of protein or cellular debris.

transurethral resection: (Usually of prostate.) Visualizing the prostate through the urethra; removing tissue by electrocautery or sharp dissection.

tricyclic antidepressants (TCAs): Any of a group of antidepressant drugs, such as amitriptyline, that contain three fused benzene rings and that block the reuptake of the neurotransmitters norepinephrine and serotonin in the central nervous system.

tubal embryo transplant: Eggs that are fertilized in the laboratory are deposited in the fallopian tubes surgically or by catheterization.

tympanoplasty: Surgery to reconstruct or repair the eardrum.


urea: Chief nitrogenous constituent of urine.

uremia: Toxic condition associated with chronic renal failure and produced by excess levels of urea, creatinine, and other nitrogen-based compounds in the blood.

urolith: Concretion, or stone, within the urinary tract.

urticaria: Vascular reaction of the skin characterized by the temporary eruption of wheals; hives.

uvulopalatopharyngoplasty: A procedure that removes excess tissue in the throat to make the airway wider; often used to treat obstructive sleep apnea.


varices: Abnormally dilated and twisted veins, arteries, or lymph nodes.

varicocele: Dilation of the complex network of veins that comprise part of the spermatic cord to form a palpable swelling within the scrotum.

vasoconstriction: Decrease in the diameter of blood vessels.

vasodilator: Drug or agent causing relaxation and expansion of the blood vessels.

vasopressin: Hormone secreted by the hypothalamus that raises blood pressure, increases peristalsis, and promotes resorption of water by the kidney. Synthetic or prepared extracts are administered as antidiuretics. Also known as antidiuretic hormone (ADH).

ventricle: Cavity in an organ, for instance the brain or the heart.

ventricular septal rupture: Breakage or tear in the septum between the left and right ventricles of the heart.

vertigo: Sensation of spinning around in space or of having objects spin around oneself.

villi (intestinal): Tiny fingerlike projections lining the interior of the small intestine that absorb fluid and nutrients.

virulence: Strength of a disease, its capacity to overcome the resistance of the organism.

visceral: Pertaining to the cavity containing internal organs.


wheal: Generally round, transient elevation of the skin, which is white in the center, with pale red edges; often accompanied by itching.


zygote intrafallopian transfer (ZIFT): In vitro fertilization in which a woman’s ova are surgically removed and mixed with her partner’s sperm; the resulting zygotes are placed in her fallopian tube.