Dictionary

Body systems

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

dandruffWhite or yellow flakes of dead skin shed from the scalp.

dawn phenomenonA rise in blood glucose in the early morning hours, roughly 4 to 8 a.m., without a low glucose during the night.

decelerationA temporary drop in the fetal heart rate below its baseline, seen on a fetal monitor.

decerebrate posturingAn abnormal body position with the arms and legs held stiff and straight, the arms turned inward and the toes pointed.

decompensationThe point at which an organ or the body can no longer make up for a disease, so it stops working well enough.

decorticate posturingAn abnormal body position with the arms bent in toward the chest, the hands clenched into fists and the legs held stiff and straight.

decreased cardiac outputA nursing diagnosis used when the heart does not pump enough blood to meet the body's needs.

deep vein thrombosisA blood clot in a deep vein, most often in the leg or pelvis.

defecationPassing stool out of the body through the anus.

defibrillationAn electric shock given to the heart to stop a chaotic, life-threatening rhythm so a normal rhythm can return.

deficiencyA lack of something the body needs, such as a vitamin, mineral, hormone or enzyme.

deformityA body part that is out of its normal shape or position.

dehiscenceThe splitting open of the edges of a wound that had been closed, such as a surgical incision.

dehydrationA state in which the body has lost more water than it has taken in.

deliriumA sudden state of confusion and poor attention that comes and goes over hours or days.

delirium tremensThe most severe form of alcohol withdrawal, with sudden confusion and overactivity of the nervous system.

deltoidThe thick, triangle-shaped muscle that covers the shoulder and lifts the arm out to the side.

delusionA firm, false belief that a person holds onto even when there is clear proof against it.

dementiaA long-term, usually worsening decline in memory and thinking that is serious enough to affect daily life.

dendriteOne of the short, branching parts of a nerve cell that receive signals from other cells.

dental cariesTooth decay: damage to the hard outer layers of a tooth that forms holes (cavities).

dependenceA state in which the body has adapted to a drug, so that stopping it suddenly causes withdrawal symptoms.

depolarizationThe change in electrical charge across a nerve or muscle cell's membrane that sets off a signal or a contraction.

depressionA mood disorder of lasting sadness or loss of interest that affects thinking, sleep, appetite and daily life.

depressive disorderA mental health condition of lasting low mood or loss of interest that gets in the way of daily life.

dermatitisInflammation of the skin.

dermisThe thick layer of skin under the epidermis that holds blood vessels, nerves, hair roots and glands.

developmentalRelating to how a person grows and changes in body, mind and behavior across their life.

developmental disabilityA lifelong condition, starting in childhood, that limits a person's physical, learning, language or behavior skills.

developmental dysplasia of the hipA condition in which the hip socket is too shallow to hold the top of the thigh bone firmly in place.

developmental milestoneA skill that most children can do by a certain age, such as smiling, sitting, walking or saying words.

developmental stageA period of life, such as infancy or adolescence, with its own typical abilities, needs and tasks.

diabetes insipidusA disorder of antidiuretic hormone: the body makes too little of it, or the kidneys do not respond to it.

diabetes mellitusA long-term disease in which blood glucose stays high because the body makes too little insulin or cannot use it well.

diabetic ketoacidosisA state of high blood glucose, ketones in the blood and acidic blood, caused by a lack of insulin.

diabetic retinopathyDamage to the small blood vessels of the retina caused by diabetes.

dialysateThe fluid used in dialysis to pull waste products and extra fluid out of the blood.

dialysisA treatment that removes wastes and extra fluid from the blood when the kidneys can no longer do it.

diaper dermatitisIrritation and redness of the skin in the area covered by a diaper.

diaphragmThe dome-shaped sheet of muscle under the lungs that is the main muscle of breathing; also the flat side of a stethoscope.

diarrheaLoose or watery stools, usually three or more times a day or more often than normal for the person.

diastoleThe part of each heartbeat when the heart muscle relaxes and the chambers fill with blood.

diastolicRelating to diastole, the part of each heartbeat when the heart muscle relaxes and its chambers fill with blood.

dietaryHaving to do with the food and drink a person takes in.

diffusionThe movement of particles from an area where they are more concentrated to one where they are less concentrated.

digestionThe process of breaking food down into small parts the body can absorb and use.

digestiveHaving to do with digestion, the breakdown of food into parts the body can absorb.

digestive systemThe organs that take in food, break it down, absorb nutrients and get rid of waste.

dilateTo widen or open up.

dilationThe widening or opening up of a body part, such as the cervix during labor, the pupils or a blood vessel.