morphine A powerful narcotic agent that has strong analgesic (pain relief) action and other significant effects on the central nervous system. It is dangerously addicting. Morphine is a naturally occurring member of a large chemical class of compounds called alkaloids. The name, which derives from Morpheus (the mythologic god of dreams) was coined in 1805…
morphology 1 Literally, the study of form (structure). 2 A form itself.
Morquio syndrome A form of mucopolysaccharidosis that is characterized by an inability to break down keratan sulfate, which leads to abnormal accumulation of keratan sulfate in muscle and skeletal tissues. This in turn can lead to abnormalities of the skeleton, muscles, skin, teeth, and muscular organs. Diagnosis is made by examining leukocytes and cultured skin…
mortality 1 The condition of being mortal, of eventually having to die. The opposite of mortality is immortality. 2 The rate of death.
mosaic A person or a tissue that contains two or more types of genetically different cells. All females are mosaics because of X-chromosome inactivation (lyonization). Mosaic patterns can affect the way genetic disorders are expressed. For example, about 5 percent of people with Down syndrome have a mosaic variant in which only some cells have…
mother 1 The female parent. 2 To produce offspring as a female. 3 A cell or another structure from which similar cells or structures are formed. Such a cell might be referred to as the mother cell. 4 To provide maternal protection, guidance, and nurturing to a child or children.
motility study, antro-duodenal A study for detecting and recording the contractions of the muscles of the stomach and the first part of the small intestine (the duodenum). An antro-duodenal motility study is performed to diagnose problems in the way the muscles of the stomach and small intestine are working. To conduct the study, a tube…
motion sickness A disorder of the sense of balance and equilibrium and, hence, the sense of spatial orientation that is caused by repeated motion such as from the swell of the sea, the movement of a car, or the motion of a plane in turbulent air. Motion sickness is due to irritation of a portion…
MMRV A combination vaccine against measles, mumps, rubella, and varicella.
MND Motor neuron disease.
Mohs surgery A type of surgery that is used for the treatment of skin cancer, especially basal cell or squamous cell carcinoma of the skin. Mohs surgery is designed to remove all the cancerous tissue while removing as little of the healthy tissue as possible. This type of surgery is especially helpful when the physician…
molar 1 One of the large teeth at the back of the mouth. The molars are well adapted to grinding. 2 Relating to or associated with a mass within the uterus that is formed by degeneration of partly developed products of conception.