ear canal: A tube leading from the eardrum to the outer ear.
eardrum: A thin membrane separating the ear canal and middle ear.
earwax: A substance that lubricates the inner ear and helps protect it from dirt, damage, and infections.
EBCT: Abbreviation for electron-beam computed tomography, a high-speed imaging technology use to evaluate the heart and measure calcium deposits in arteries.
eccentric action: When muscles move joints by lengthening. Also known as cerumen.
ECG: An abbreviation for electrocardiogram, a test that measures the electrical activity of the heart and detects heart problems.
echocardiography: A diagnostic tool that uses high-frequency sound waves (ultrasound) to make images of the heart's size, structure and motion.
eclampsia: A serious condition related to high blood pressure that can threaten the life of a pregnant woman and her fetus.
ectopic pregnancy: Pregnancy in which a fertilized egg implants in an abnormal location outside the uterus, usually in the fallopian tubes. Ending the pregnancy is necessary.
ectropion: When an eyelid, usually the lower one, flips outward so that the inner surface is exposed.
eczema: A condition in which areas of the skin are dry, itchy, red, and cracked. Also known as atopic dermatitis.
ED: Commonly used abbreviation for erectile dysfunction, the inability to get or maintain an erection sufficient for intercourse.
edema: Swelling caused by abnormal accumulation of fluid in tissues.
EEG: Abbreviation for electroencephalogram, a test that measures the electrical activity of the brain and detects problems.
effusion: An abnormal buildup of fluid in a joint or tissue.
eighth cranial nerve: A nerve responsible transmitting sound and information about balance to the brain. Also called the auditory nerve.
ejaculation: A sudden discharge of a fluid from a duct; often used to describe the expulsion of seminal fluid from the urethra of the penis during orgasm.
ejection fraction: The percent of blood pumped out of the left ventricle with each heartbeat. A normal ejection fraction is in the range of 55% to 70%.
EKG: An abbreviation for electrocardiogram, a test that measures the electrical activity of the heart and detects heart problems.
elastin: A flexible, stretchy protein found in skin and connective tissue.
electrocardiogram: A test that measures the electrical activity of the heart and detects heart problems.
electroencephalogram: A test that measures the electrical activity of the brain and detects problems.
electrolysis: A permanent hair removal technique that destroys follicles one at a time with a hair-thin needle inserted into the base of the follicle.
electrolyte: Minerals in the body that are electrically charged and play an important role in body processes, such as regulating fluid levels in the body. Examples include calcium and sodium.
electromyography: A test that checks the health of muscles and the nerves that control them.
electron-beam computed tomography: A high-speed imaging technology use to evaluate the heart and measure calcium deposits in arteries. Sometimes referred to as EBCT.
electrophysiologic testing: A procedure used to provoke known or suspected arrhythmias.
elimination diets: A way of diagnosing food allergies in which suspected foods are removed from the diet one at a time until the food causing a problem is found.
ellagic acid: A chemical found in certain plants, such as raspberries and strawberries, that might help protect against cancer.
embolic stroke: A type of stroke that occurs when a blood clot that has formed elsewhere in the body breaks off and travels through the bloodstream until it blocks an artery that normally supplies blood to the brain.
embolism: Blockage of a blood vessel by a clot (an embolus) that has traveled from another part of the body.
embolus: A blood clot or particle that forms in one part of the body then moves through the bloodstream and lodges in a blood vessel elsewhere, blocking blood flow.
emetic: Any drug or other substance used to cause vomiting.
EMG: Abbreviation for electromyography—a test that checks the health of muscles and the nerves that control them.
emission: The discharge or release of a substance, usually a fluid.
emmenagogue: Herbs that stimulate menstrual blood flow.
enamel: The hard outside layer of tooth material.
encephalitis: A severe and sometimes deadly inflammation of the brain that can be caused by a number of different viruses.
encoding: A multistage process by which sensation, perception, or thought is transformed into neural representations that can be stored in memory.
endarterectomy: Surgical removal of plaque or blood clots in an artery.
endemic: Continually present among people in a geographic region.
endocarditis: An inflammation of the heart lining or valves, usually caused by bacterial infection.
endocardium: The inner layer of the wall of the heart.
endogenous opioids: Painkilling substances made by the body.
endometrium: The lining of the uterus.
endorphins: Substances in the body that reduce pain and create a feeling of well-being.
endoscope: A thin, flexible tube equipped with a light and camera that is used to see inside an organ or body cavity.
endoscopy: Inserting a flexible tube equipped with a light and camera into the body to see inside a body cavity or organ.
endothelins: Proteins that cause blood vessels to narrow and blood pressure to rise.
endothelium-derived relaxing factor: Chemicals in the body that cause blood vessels to expand or relax, lowering blood pressure. Often referred to as EDRF.
end-stage renal disease: Complete, or nearly complete, kidney failure. Dialysis or a transplant is needed for survival.
enkephalin: A chemical produced in the brain that reduces pain.
enteric nervous system: Part of the nervous system that controls the gastrointestinal system.
enteropathic: Disease affecting the intestinal tract.
enthesis: A place where a ligament, tendon, or muscle attaches to bone.
entropion: An eyelid, usually the lower lid, which folds inward so that the eyelashes rub against and irritate the surface of the eye.
enzyme: A substance that speeds up another chemical reaction. For example, digestive enzymes help speed up the digestion of food.
eosinophils: White blood cells that play an important role in allergic reactions.
epicardium: The outer layer of the wall of the heart.
epicondylitis: Pain and swelling in the tendons in the elbow, usually because of overuse.
epidemic: The occurrence of more cases of disease than expected within a population in a geographic area over a set period of time.
epidemiological study: An investigation of the links between certain behaviors or risk factors and the occurrence of disease or good health in a population.
epidermis: The outermost layer of skin.
epidural space: The space between the spinal cord and the bones of the spinal column where painkillers are injected.
epinephrine: A chemical that narrows blood vessels, increases heart rate, and helps trigger the fight-or-flight response to danger. Also called adrenaline.
EpiPen: A device used to inject a dose of medication (epinephrine) when a severe allergic reaction occurs.
epithelial cells: Cells which line organs and structures in the body, protecting or enclosing them.
epithelium: A layer of cells which lines organs and structures in the body, protecting or enclosing them.
erectile dysfunction: The inability to get or maintain an erection sufficient for intercourse. Sometimes referred to as ED.
erector spinae: A group of muscles and tendons in the back.
ergonomics: Designing and arranging work objects so that the user is comfortable, efficient, and less likely to be injured.
ergots: Substances derived from or made from a fungus; often used to treat headache.
eructation: The act of bringing up air from the stomach through the mouth with a characteristic sound. Commonly known as belching.
erythema: Redness of the skin because of widening of capillaries just below the surface of the skin.
erythema nodosum: Painful, red lumps beneath the skin; associated with Crohn's disease.
erythrocyte sedimentation rate: A test involving red blood cells; used to check for different infections, inflammations, and cancers.
erythropoietin: A hormone that controls red blood cell production.
esophageal manometry: A test to measure the pressure inside the lower part of the esophagus.
esophagitis: Irritation and swelling of the esophagus.
esophagus: The tube that carries food and liquids from the mouth to the stomach.
essential fats: Two fatty acids, omega-3 and omega-6, that the body needs for good health but can't make so they must come from foods and supplements.
essential hypertension: High blood pressure with no known cause; also called primary hypertension.
esterified estrogens: Artificially made hormones used to manage menopausal symptoms.
esthetician: A person who specializes in non-medical skin care and beauty treatments.
estradiol: The primary form of the sex hormone estrogen produced by women.
estrogen: The main sex hormone in women.
estrogen receptor: A site on the surface of some cells to which estrogen molecules attach.
estrogen-replacement therapy: Use of medications containing the sex hormone estrogen by women to replace naturally-occurring estrogen lost during menopause.
etidronate: A medication used to treat bone loss due to Paget's disease.
eustachian tube: A tube connecting the middle ear and the back of the nose that lets air into the middle ear.
euthyroid: Having a thyroid gland that works properly.
excitatory neurotransmitter: A chemical that forwards a message from one neuron to another.
excitotoxin: A brain chemical that damages neurons.
executive functions: The component of thinking that organizes, plans, decides, and inhibits inappropriate impulses.
exercise: A structured program of physical activity that helps an individual become physically fit.
exercise stress test: The use of a treadmill, stationary bicycle, or other exercise machine while hooked up to heart-monitoring equipment. The test is used to determine if the heart's blood supply is sufficient and if the rhythm remains normal when the heart is stressed.
exophthalmos: A protrusion or bulging of the eye that occurs with Graves' eye disease. Tissues behind the eye swell, forcing the eyeball forward. Also called proptosis.
exostosis: Abnormal bony growths in the ear caused by swimming regularly in cold water. Sometimes called surfer's ear.
experience sampling: A research technique for learning about people's activity patterns and psychological processes that involves paging them at random times to obtain brief reports.
expression hopping: A common phenomenon whereby people jump to a different expression of addiction. For example, people with heroin addiction might transition to alcohol addiction. Hopping is especially common during the recovery process.
expression of addiction: The specific way in which a person manifests addiction, for example, through the use of cocaine, or compulsive gambling.
extend: To straighten out a joint (for example, extending the arms overhead).
external otitis: An infection or irritation of the outer ear, ear canal, or both. Also called swimmer's ear.
extracapsular cataract surgery: A surgical technique to remove a cataract from the eye.
extract: A product made from substances that are drawn out of a plant or herb.
extraocular muscles: Six paired muscles that direct the eyes' circular, side-to-side, and up-and-down movements.
extrinsic factor: An outside factor that has an effect on a person's environment or well-being.