Medical Dictionary: so A-C

Flashcards of medical terms for review.

5-alpha reductase

A chemical that changes the sex hormone testosterone into dihydrotestosterone, which can cause the prostate gland to grow abnormally.

Abdominal muscles

A sheet of muscles on the front of the abdomen, between the ribcage and the pelvis.

Abdominoplasty

A procedure to remove excess abdominal skin and tighten the underlying stomach muscles; also known as a tummy tuck.

Abduction

Movement of a body part, such as an arm or leg, away from the center of the body.

Ablation

A form of treatment that uses electrical energy, heat, cold, alcohol, or other modalities to destroy a small section of damaged tissue.

Abrasion

A scraping or rubbing away of the skin or other surface.

Abscess

Pus that collects in a pocket of swollen, red tissue, often on the surface of the skin.

Abutment

A tooth or implant to which a fixed prosthesis is anchored.

Acceptance-based therapies

Psychotherapy techniques that use mindfulness to help a person recognize and accept thoughts and feelings but not be controlled by them.

Accommodation

The eye's ability to focus on objects that are close.

ACE

Abbreviation for angiotensin-converting enzyme, an enzyme that converts the inactive form of the protein angiotensin (angiotensin I) to its active form—angiotensin II.

Acetabulum

A curved, bowl-shaped depression in the outer part of the hipbone where the ball-shaped portion at the top of the thighbone fits to form the hip joint.

Acetaldehyde

The main breakdown product of alcohol metabolism; accumulation in the bloodstream may produce flushing and vomiting.

Acetaminophen

A common, over-the-counter drug used to reduce fever and relieve mild to moderate pain, but which does not reduce redness or swelling (inflammation).

Acetylcholine

A neurotransmitter (chemical messenger) that sends signals between brain cells and plays roles in attention, learning, and memory.

Achilles’ tendon

A band of connective tissue that connects the calf muscle to the heel bone; prone to swelling and/or rupture.

Achlorhydria

A condition in which the stomach produces little or no acid, which can affect digestion, cause stomach pain, and keep the body from absorbing vitamins and nutrients.

Acne

An inflammatory disease resulting from excess sebum production, follicle plugging, and increased bacterial production.

Acquired immunodeficiency syndrome

Usually abbreviated as AIDS, the most advanced stage of infection with HIV, which can severely weaken the immune system.

Acquisition

The term given to the brain's absorption of new information to begin creating a memory.

Acromioclavicular joint

A shoulder joint that connects the clavicle to the scapula.

Actin

One of the proteins that allows cells to move and muscles to contract.

Actinic keratosis

Scaly pink or red-brown raised spots or patches on the skin caused by overexposure to the sun; may be a precursor to skin cancer.

Active surveillance

A strategy for managing early prostate cancer in which a man has regular checkups but does not undergo treatment until the disease shows signs of worsening.

Acupressure

Using the thumb or fingers to apply pressure to particular spots, or pressure points, on the body in order to relieve pain.

Acupuncture

A treatment based on Chinese medicine in which thin needles are inserted into the skin at specific points on the body to treat pain and various health problems and to reduce stress.

Acute

A condition that comes on suddenly, often with severe, but short-lived symptoms.

Addiction

Loss of control over indulging in a substance or performing an action or behavior, and continued craving for it despite negative consequences.

Adaptive immunity

Ability of the body to learn to fight specific infections after being exposed to the germs that cause them.

Acute pain

Severe pain that occurs suddenly and usually lasts for a short while.

Adduction

Movement of a body part toward or across the midline.

Adenocarcinoma

A type of cancer that grows in the layer of tissue known as the epithelium, which lines organs and structures in the body.

Adenoma

A benign growth found in the layer of cells that lines certain organs (epithelial cells).

Adipose tissue

Fat-filled tissue.

Adhesion

A band of scar-like tissue that forms between two surfaces inside the body, connecting tissues or organs which are not normally connected.

ATP

Abbreviation for adenosine triphosphate, an energy-storing molecule found in all human cells.

Adjuvant therapy

Extra therapy given after a primary treatment, to increase the effectiveness of the primary treatment (e.g., chemotherapy after surgery or radiation for cancer).

Adrenal glands

Glands that sit on top of each kidney and secrete stress hormones.

Adrenaline

A stress hormone that puts the body on high alert, increasing heart rate, breathing, energy, and blood pressure; also called epinephrine.

Adulterant

An ingredient in a medicinal product (herb, supplement, or prescription drug) that dilutes the purity of the product and does not contribute to its therapeutic effects.

Advance care directive

A legal document that describes the kind of medical care a person wants if an accident or illness leaves him or her unable to make or communicate decisions.

Aerobic

Any process that requires oxygen; often used to describe a form of exercise.

Agonist

1) A substance that triggers a physiological response when it combines with a receptor. 2) A muscle whose contraction is opposed by another muscle.

After-cataract

Clouding of the lens of the eye that can occur months or years after cataract surgery.

AIDS

Acquired Immunodeficiency Syndrome

Agoraphobia

Fear and avoidance of public places and spaces.

Albinism

A group of inherited conditions that typically appear as a reduction or absence of melanin pigments in the skin, hair, and eyes.

Albumin

A protein made by the liver. Abnormal levels of this substance may indicate liver or kidney disease.

Albuminuria

High amounts of albumin (a protein made by the liver) in the urine, possibly indicating kidney dysfunction.

Alcohol Abuse

Continuing consumption of alcohol despite alcohol-related social or interpersonal problems.

Alcohol Dehydrogenase

A liver enzyme that metabolizes alcohol into a substance called acetaldehyde, which is toxic. Sometimes referred to as ADH.

Alcohol Dependence

A chronic, progressive disease characterized by excessive and often compulsive drinking, impaired control over drinking, use of alcohol despite adverse consequences, and withdrawal symptoms when alcohol use is discontinued. Also known as alcoholism.

Aldosterone

A hormone secreted by the adrenal glands that helps regulate blood pressure by controlling sodium and potassium levels in the body.

alimentary canal

Another term for the gastrointestinal, or digestive, tract.

Allele

One of two or more versions of a gene. Different alleles produce variations in inherited characteristics, such as eye color.

Allergen

A substance such as fur, pollen, or dust that produces an allergic reaction.

Allergic

Having a sensitivity to one or more normally harmless substances.

Allergic Rhinitis

A seasonal or year-round allergic condition marked by sneezing, runny nose, and congestion. The most common type of allergy, it is caused by an IgE-mediated immune response to inhaled airborne allergens.

Allergy

An immune system reaction (for example, rash, fever, sneezing, or headaches) to something that is normally harmless.

Allodynia

Pain resulting from something not normally painful, such as a light touch.

Alopecia Areata

An autoimmune condition that appears as patchy hair loss on the scalp that may result in permanent hair loss.

Alopecia Totalis

Hair loss that involves the entire scalp.

Alpha Blockers

A group of drugs that lower blood pressure by blocking the effects of adrenaline or adrenaline-like substances on cells' alpha receptors. Used to treat some prostate gland problems.

Alpha Cells

Cells in the pancreas that produce the hormone glucagon.

Alpha Hydroxy Acids

Fruit-derived acids used in creams and lotions to act as exfoliants.

Alpha Waves

A type of brain wave generated when a person is relaxed, awake, and receiving no visual input (eyes closed or in the dark).

Alzheimer's Disease

A progressive brain disease that causes memory loss, impaired thinking, and personality changes.

Alveoli

Tiny air sacs in the lung. They are where oxygen enters and carbon dioxide leaves the bloodstream.

Ambulatory

Able to walk; not confined to a bed.

AMD

Abbreviation for age-related macular degeneration, a potentially blinding condition that destroys sharp central vision.

Amnesia

Unusual memory loss or forgetfulness.

Amputation

The surgical removal of a limb or other body part.

Amsler Grid

A tool used to check for vision problems, particularly macular degeneration. The grid looks like graph paper with a dot in the center.

Amygdala

Part of the brain involved in memory and emotion.

Amyloid

A protein that collects in tissues when certain diseases, including Alzheimer’s disease, are present.

Anaerobic

Any process that doesn’t require oxygen. Often refers to a form of short, high intensity exercise, known as anaerobic exercise.

Anagen

The active growth phase of the hair-growth cycle.

Anal Canal

The last inch of the large intestine, leading to the anal opening.

Analgesia

Absence of pain.

Analgestic

A drug or other substance such as aspirin, acetaminophen, or morphine that is used to relieve pain.

Anaphylaxis

A severe allergic reaction, causing symptoms spanning from itching and swelling to trouble breathing, convulsions, shock, and coma.

Androgen

Any of a group of male sex hormones, including testosterone, that controls male characteristics such as beard growth.

Anemia

Having a lower than normal amount of red blood cells or hemoglobin (an oxygen-carrying protein inside red blood cells), leading to low energy, weakness, and other symptoms.

Anencephaly

A birth defect in which an infant is born without most of the brain or without the skull bones covering the brain.

Anesthesia

Temporarily blocking sensation, especially the feeling of pain.

Aneurysm

A bulge or swelling on a portion of a blood vessel, due to weakness in the wall of that vessel.

Angina Pectoris

Temporary chest pain that occurs when the heart isn’t getting enough oxygen and blood, usually occurring in response to physical activity or stress.

Angiogenesis

The formation of new blood vessels.

Angiography

A test that shows how blood moves through the blood vessels and heart. It uses x-rays and the injection of a fluid called a contrast agent that can be seen on the x-rays.

Angioplasty

A procedure used to open blocked or narrowed arteries, most commonly by inserting a thin tube, or catheter, into the affected artery and inflating a balloon.

angiotesin

A protein that raises blood pressure by narrowing blood vessels and causing the kidneys to store more sodium and water.

Angiotesin I

An inactive form of the protein angiotensin. It is the precursor to the active form, angiotensin II.

Angiotesin II

The active form of the protein angiotensin, which raises blood pressure by narrowing blood vessels and causing the kidneys to store more sodium and water.

Ankle=Brachial Index

A test that compares blood pressure at the ankle with blood pressure at the elbow. A difference between the two indicates the presence of peripheral artery disease.

Arther-

A prefix meaning 'joint'

Arthritis

A condition in which joints are inflamed, causing pain, stiffness, swelling, and sometimes loss of movement.

Analgesic

A drug or other substance such as aspirin, acetaminophen, or morphine that is used to relieve pain.

Artery

A blood vessel that carries blood away from the heart and to various parts of the body.