Glossary - M
Displaying glossary terms beginning with the letter M: 1 - 50 of 111 in total
- macrocytic anemia
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The presence of larger-than-normal red blood cells in circulation?even though there are too few of them?caused by lack of folate and vitamin B12.
- macronutrients
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Substances that provide energy and that the body needs for growth. The main categories are: fat, carbohydrate, and protein.
- macrophage
- macula
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The area in the center of the retina that produces sharp, clear central vision and allows one to see fine detail.
- macular degeneration
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An eye disease that slowly destroys sharp, clear central vision.
- macular edema
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The build-up of fluid in the macula caused by fluid leaking from blood vessels in the eye. It can blur and damage vision.
- Magenblase syndrome
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Swallowing too much air during a meal, causing excessive gas and great discomfort. Also known as stomach bubble syndrome.
- magnetic resonance imaging (MRI)
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A scan that creates detailed pictures of internal organs. MRIs use radio waves, a strong magnetic field, and a computer to produce images of organs and internal tissues.
- maintenance of wakefulness test
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A test to measure sleepiness during the day. A tester measures how long it takes a person who is sitting up in a chair or bed to fall asleep after he or she has been asked to stay awake.
- major depression
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Depression that interferes with daily life for an extended period. Episodes of major depression during bereavement can be distinguished from normal sadness by such symptoms as persistent feelings of worthlessness, thoughts about death, feelings of guilt, persistent trouble functioning, and marked mental and physical sluggishness.Related health topics: Bulimia
- major histocompatibility complex (MHC) molecule
- maladaptive stress response
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An unhealthy physiological response to stressors, in which the stress response often does not turn off even when the stressor disappears
- malaise
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A general feeling of illness that can be a sign of disease.Related health topics: End-Stage Renal Disease
- malignant
- malignant hypertension
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A dangerous type of high blood pressure marked by an unusually sudden rise in blood pressure to very high levels, often accompanied by headache, blurred vision, and seizures.
- malnutrition
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Failure to eat or to properly absorb the nutrients needed for good health.
- mast cell
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A cell involved in allergic reactions. When stimulated, it releases chemicals like histamine that signal infection and cause inflammation.
- mastoid bone
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The bone in the skull behind the ear.
- mastopexy (breast lift)
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A cosmetic surgery to reshape and lift drooping breasts.
- masturbation
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Sexual self-stimulation.
- maximizer
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A person who typically evaluates all options before making a decision, in an effort to identify the perfect choice, and who never settles for second-best.
- meal plan
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A detailed guide outlining the amounts and types of food a person should eat each day.
- Medicaid
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A government program that offers health care for low-income Americans of any age.
- Medicare
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A government program that offers health care for Americans ages 65 and older.
- Medigap insurance
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Health insurance policies that fill in the holes in Medicare coverage.
- medulla
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Refers to the middle of something.
- megaloblastic anemia
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Fewer than normal healthy red blood cells in circulation, caused by a lack of folate or vitamin B12. Red cells become large and deformed, and are unable to carry oxygen efficiently.
- meglitinides
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A type of medication taken to treat type 2 diabetes.
- melanin
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A substance that gives the skin, hair, and eyes their natural color.
- melanocytes
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Cells located deep in the epidermis that produce melanin, the pigment that colors skin.
- melanoma
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The most dangerous type of skin cancer.Related health topics: Head and Neck Cancer
- melatonin
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A hormone that regulates the body's sleep-wake cycle.
- membrane
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A thin layer of tissue that surrounds or lines organs or cavities.Related health topics: Endometriosis, Muscular Dystrophy
- memory T cells and B cells
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Immune cells that remember harmful agents that have entered the body in the past. When they spot the substance again, they spur the immune system to eliminate the invader.
- Ménière's disease
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An illness caused by a fluid imbalance in the inner ear.
- meninges
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The three membranes that cover and protect the brain and spinal cord.
- meningitis
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Swelling of the membranes that cover and protect the brain and spinal cord.
- menopause
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The point marking the end of menstruation, officially designated as one year after a woman's final period.
- metabolic equivalents (METs)
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Units used to estimate the oxygen consumption, or metabolic cost, of physical activity, and, hence, its intensity. One MET is the estimated energy cost of the body at rest.Related health topics: Breast Cancer, Coronary Artery Disease, Endometriosis, Fallopian Tube Cancer, Osteoporosis, Uterine Cancer
- metabolic syndrome
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A cluster of risk factors that accelerate the progression of heart disease.
- metabolism
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The chemical reactions that occur in all living organisms to maintain life. An example is converting food into energy that the body needs to function.
- metastasis
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Related health topics: Esophageal Cancer, Type 2 Diabetes Mellitus
- metered-dose inhaler
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A device that delivers a specific dose of an inhaled asthma medication.Related health topics: Chondrosarcoma, Metastatic Brain Tumors
- Methanobrevibacter smithii
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Bacteria in the gut that help with the digestion of complex sugars.
- microalbuminuria
- microaneurysm
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A tiny bulge that develops in the wall of a blood vessel.
- microbe
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A microorganism.
- microdermabrasion
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A cosmetic procedure in which tiny crystals under high pressure are sprayed on the face. This buffs away the outer layer of skin, eliminates fine lines, and improves the look of the skin.
- microgram (mcg)
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A unit of mass, equal to one-thousandth of a milligram.
- micronized
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Reducing a substance to very small particles.