Dictionary

Body systems

Anatomy and the conditions of each body system, from the heart and lungs to the skin.

B-type natriuretic peptideA hormone released by the heart's lower chambers when they are stretched, measured with a blood test.

bacteremiaThe presence of bacteria in the bloodstream.

Barrett esophagusA change in the lining of the lower esophagus in which its normal cells are replaced by cells like those lining the intestine.

Bartholin glandsTwo small glands, one on each side of the vaginal opening, that make fluid to moisten the vagina.

basal cell carcinomaThe most common type of skin cancer, which starts in the basal cells at the bottom of the skin's outer layer.

basal gangliaGroups of nerve cells deep inside the brain that help start, stop and smooth out movements.

basophilThe least common type of white blood cell, which releases histamine during allergic and inflammatory reactions.

Bell palsySudden weakness or loss of movement on one side of the face, from a problem with the facial nerve.

benignNot cancerous: describing a growth that does not invade nearby tissue or spread; also, mild and not dangerous.

benign prostatic hyperplasiaA prostate gland that has grown larger than normal, from growth that is not cancer.

beta cellA cell in the pancreas that makes and releases insulin.

bicarbonateA base in the blood that balances acid; the kidneys control it, and its level is measured on blood gas and chemistry tests.

bilateralHaving to do with both sides of the body.

bileA yellow-green fluid made by the liver and stored in the gallbladder that helps digest fats.

bile ductOne of the tubes that carry bile from the liver and gallbladder to the small intestine.

bipolarHaving two poles or two opposite ends; most often used as a short form of bipolar disorder.

bipolar disorderA mental health condition with periods of very high mood and energy (mania) and, often, periods of depression.

birth defectA problem in how a part of the body is formed or works that is present when a baby is born.

bladderThe hollow, stretchy organ in the lower belly that stores urine until it leaves the body.

bleedingBlood escaping from a blood vessel, either out of the body or inside it.

blisterA raised bubble of skin filled with clear fluid.

blood cellAny of the cells carried in the blood: red cells, white cells or platelets.

blood clotA soft, gel-like clump that forms when blood changes from a liquid to a solid.

blood pressureThe force of blood pushing against the walls of the arteries, written as systolic over diastolic in mm Hg.

blood productAny part of donated blood prepared for transfusion, such as red cells, plasma or platelets.

blood transfusionGiving blood, or a part of blood, from a donor into a person's vein.

bloodstreamThe blood flowing through the body's blood vessels.

bloodstream infectionAn infection in which bacteria or fungi are growing in the blood.

body fluidAny liquid made in or found inside the body, such as blood, urine, saliva or fluid inside cells.

body temperatureThe degree of heat of the body, measured with a thermometer as one of the vital signs.

bone densityThe amount of mineral, mostly calcium, packed into a given area of bone, which reflects how strong the bone is.

bone marrowThe soft, spongy tissue inside bones that makes blood cells.

bony prominenceA place where a bone lies close under the skin with little fat or muscle over it, such as the heel or tailbone.

bowelThe intestine: the long tube of the digestive tract from the stomach to the anus.

bowel movementThe passing of stool (feces) from the bowel out through the anus.

bowel obstructionA partial or complete blockage that stops food, fluid and gas from moving through the small or large bowel.

bradycardiaA heart rate slower than normal; in an adult, fewer than 60 beats per minute.

bradykininA small protein in the body that widens blood vessels, makes them leak fluid and causes pain.

bradypneaBreathing that is slower than normal for the person's age.

brain stemThe lowest part of the brain, which connects it to the spinal cord and controls breathing, heart rate and other automatic functions.

brain tumorAn abnormal mass of cells growing in or on the brain, which may be cancerous or not.

Braxton Hicks contractionsIrregular tightening of the uterus during pregnancy that does not open the cervix; sometimes called practice contractions.

breastEither of the two raised areas on the front of the chest; in women they contain glands that make milk.

breast cancerCancer that starts in the cells of the breast.

breast milkThe milk made by the breasts to feed a baby.

breastfeedingFeeding a baby with milk directly from the breast.

breathingMoving air in and out of the lungs.

breathing exerciseA practiced way of breathing used to expand the lungs, move air better or relax.

breech presentationA position of the fetus in which the buttocks or feet, instead of the head, are lowest in the uterus.

Broca areaAn area in the frontal lobe of the brain, usually on the left side, that controls the production of speech.