ABCDEFGHIJKLMNOPQRSTUVWXYZ

Glossary - D

Displaying glossary terms beginning with the letter D: 1 - 50 of 102 in total
d-limonene
A substance found in citrus fruits.
D2 receptor
A type of dopamine receptor (see neurotransmitter receptors) that seems to be particularly important in addiction.
daidzein
A substance found in soybeans.
daily value (DV)
A guide to the amount of nutrients in a given food; Daily values are given in percentages based on a 2,000-calorie-per-day diet.
dandruff (seborrheic dermatitis)
A mild and common condition that is characterized by an itchy, flaky scalp and that may extend to the ears, face, and chest.
de Quervain's tendonitis
Painful swelling of the tendons at the wrist that move the thumb.
debility
Weakness or a loss of physical strength.
decibel
A unit of measurement for the loudness of a sound. The highest decibels indicate the loudest sounds.
declarative memory
Memory for facts or events (episodic memory); also called explicit memory.
decoction
An herbal product or tea made by boiling a plant in water.
decongestant
Type of medication used to relieve nasal congestion.
deep sleep
Stage of sleep where the brain is less responsive to outside stimuli.
deep venous thrombosis
A dangerous condition in which blood clots form in veins deep in the body, usually the legs. They may break off and block blood flow in the lungs, seriously damaging organs or causing death.
defenses
Coping strategies a person adopts to make it easier to operate in the world.
defibrillation
The delivery of an electric shock to the heart to stop an abnormal rhythm and restore a normal heartbeat.
defibrillator
A device that delivers an electric shock to the heart to restore normal rhythm. Used to treat cardiac arrest and other dangerous heart rhythm problems.
degenerative disease?
Any disease in which the organs or tissues in the body are damaged progressively over time.
degenerative disk disease
Normal, and sometimes painful, deteriorations in the disks of the spine that occur with age.
degenerative joint disease
Arthritis that occurs when the cartilage in joints breaks down over time; also called osteoarthritis.
degenerative spondylolisthesis
Arthritis of the spine that worsens over time; often caused by aging.
delayed sleep phase syndrome
A pattern of falling asleep and waking up later than wanted that tends to worsen progressively over time.
delirium
Sudden, severe confusion that occurs because of a mental or physical illness
delta waves
Slow brain activity that occurs when a person is in deep sleep.
delusion
A false or irrational belief held by a person despite evidence to the contrary.
dementia
A loss of brain function that worsens over time and affects memory, thinking, behavior, and language.
dementia pugilistica
Loss of brain function, common among former boxers, caused by repeated blows to the head.
demineralization
The process by which bacteria destroy tooth enamel.
demulcent
A substance that soothes irritated tissues and mucous membranes.
dendrites
The parts of a nerve cell that receive signals from other nerve cells.
dendritic cells
Spidery-looking immune system cells that help protect the body from harmful substances.
denial
A defense mechanism characterized by the inability to recognize or admit that addiction is the cause of problems, rather than a solution or mere byproduct. Denial can also refer to the refusal to accept an upsetting reality, such as a serious illness or death or the feelings that follow either.
dental implant
A metal post inserted into the alveolar bone to support an artificial tooth or other prosthesis.
dentin
The layer of hardened tooth tissue under the enamel and around the pulp.
deoxyribonucleic acid (DNA)?
The substance found in the nucleus of cells that contains the genetic instructions for that living organism.
dermal papilla
A structure situated at the base of the hair follicle that contains nerves and blood vessels that fuel the cellular processes of the developing hair shaft.
dermatomyositis
A rare disease in which the muscles become weak and stiff and a skin rash appears.
dermis
The middle layer of skin that contains most of the skin's structures, like collagen, nerves, glands, and hair follicles.
desiccated thyroid
An extract made of dried animal thyroid glands.
detoxification
The process of removing harmful, or toxic, substances from a person's body.
detrusor instability
The sudden, strong need to urinate due to spasms in bladder muscles. Also called urge incontinence.
detrusor muscle
The layer of muscle in the bladder wall that squeezes urine out of the bladder.
detumescence
The softening of an erection.
diabetes
A disorder in which blood glucose (sugar) levels are elevated.
diabetes mellitus
A disease in which the body does not properly produce or use insulin, resulting in abnormally high levels of sugar (glucose) in the blood.
Related health topics: Flu (Influenza)
diabetic ketoacidosis
A complication of diabetes in which substances called ketones build up in the blood to dangerously high levels.
diabetic retinopathy
A complication of diabetes that occurs when the small blood vessels in the retina are damaged. It can impair vision or even lead to blindness.
diaphragm
The dome-shaped sheet of muscle at the base of the lungs that helps move air in and out of the lungs.
diastole
The relaxation phase of the normal heart cycle.
diastolic blood pressure
The bottom number of a blood pressure reading, such as 134/78. It represents the pressure in the arteries when the heart relaxes between beats.
diastolic heart failure
The inability of the heart to relax properly between beats (diastole), making it difficult for the ventricles to fill completely with blood from the atria. This can occur when the heart muscle bulks up due to overwork or other causes or when the heart muscle stiffens and loses it flexibility.