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Glossary - A

Displaying glossary terms beginning with the letter A: 1 - 50 of 222 in total
5-alpha reductase
A chemical that changes the sex hormone testosterone into a substance called dihydrotestosterone. This hormone can cause the prostate gland to grow abnormally.
abdominal muscles
A flat sheet of muscles on the front of the abdomen, between the ribcage and the pelvis
abdominoplasty (tummy tuck)
A procedure to remove excess abdominal skin and tighten the underlying stomach muscles.
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 heart 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 occurs on the surface of the skin.
Related health topics: Acute Pancreatitis
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 inhibitor
A drug used to treat high blood pressure and congestive heart failure; abbreviation of angiotensin-converting enzyme inhibitor.
acetabulum
A curved, bowl-shaped depression in the outer part of the hipbone. The ball-shaped portion at the top of the thighbone fits into this space to form the hip joint.
acetaldehyde
The main breakdown product of alcohol metabolism; accumulation of it in the bloodstream may produce flushing (a feeling of heat in the face or chest) 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 (a chemical messenger that sends signals between brain cells) that plays roles in attention, learning, and memory
Achilles' tendon
A band of connective tissue that connects the calf muscle to the heel bone. This tissue is prone to swelling and/or rupture.
achlorhydria
A condition in which the stomach produces little or no acid. This 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 (AIDS)
This disease occurs when HIV (human immunodeficiency virus) severely weakens the immune system. People with AIDS get many infections, often from diseases that don't affect people with healthy immune systems.
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. Actinic keratosis 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.
Related health topics: Prostate Cancer
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. Thin needles are inserted into the skin at specific points on the body. This therapy is used to treat pain and various health problems and to reduce stress.
Related health topics: Menopause And Perimenopause , Pain
acute
A condition that comes on suddenly, often with severe, but short-lived symptoms.
Related health topics: Asthma
acute pain
Severe pain that occurs suddenly and usually lasts a short while.
acute urinary retention
A sudden inability to empty the bladder. Causes include an enlarged prostate gland (in men) or bladder muscle problems.
adaptability
The ability of an organism to change genetically in a way that allows it to deal better with its environmental conditions.
adaptive immunity
The ability of the body to learn to fight specific infections after being exposed to the germs that cause them.
addiction
Loss of control over indulging in a substance or performing an action or behavior, and continued craving for it despite negative consequences.
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. This tissue lines organs and structures in the body, protecting or enclosing them.
adenoma
A benign growth found in the layer of cells that lines certain organs (epithelial cells).
adenosine triphosphate (ATP)
An energy-storing molecule that is found in all human cells.
adequate intake (AI)
An estimate of the amount of a nutrient needed by healthy people. The Adequate Intake is used when there isn't enough information to set a recommended dietary allowance (RDA).
adhesion
A band of scar-like tissue that forms between two surfaces inside the body, connecting tissues or organs which are not normally connected.
adipose tissue
Fat-filled tissue.
adjuvant therapy
Extra therapy given after a primary treatment, to increase the effectiveness of the primary treatment. For example, using chemotherapy after surgery or radiation treatment for cancer.
adrenal glands
Glands that sit on top of each kidney and secrete stress hormones.
adrenaline and noradrenaline
Stress hormones that put the body on high alert. Changes include faster heartbeat, more rapid breathing, greater energy, and higher blood pressure. Also called epinephrine and norepinephrine.
adult day services
Centers providing daytime services to adults who need supervision, social support, or assistance with daily activities.
adulterant
An ingredient in a medicinal product (herb, supplement, or prescription drug), which dilutes the purity of the product and does not contribute to its therapeutic effects.
advance care directive (or advance medical directive)
A legal document that describes the kind of medical care a person want if an accident or illness leaves him or her unable to make or communicate decisions.
advanced sleep phase syndrome
A pattern of falling asleep and waking up earlier than wanted that worsens progressively over time.
aerobic
Any process that requires oxygen. Often used to describe a form of exercise, aerobic exercise.
aerobic exercise
Physical activity that speeds breathing, improves heart and lung function, and offers many other health benefits. Examples include brisk walking, running, or cycling.
Related health topics: High Blood Pressure (Hypertension)
aerophagia
Excessive swallowing of air.
aesthetician
Licensed skin care professional who performs procedures such as deep cleansing, low-grade chemical peels, microdermabrasion, and postsurgical skin care.