Dictionary

dendrite A short, arm-like protuberance from a nerve cell (neuron). The tips of dendrites transmit and receive chemical messages. See also axon; neuron.

demyelination A degenerative process that erodes the myelin sheath that normally protects nerve fibers. Demyelination exposes these fibers and appears to cause problems in nerve impulse conduction. Demyelination is seen in a number of diseases, particularly multiple sclerosis.

demulcent An agent that forms a soothing, protective film when administered onto a mucous membrane surface. For example, mucilage and oils are demulcents that can relieve irritation of the bowel lining.

dementia complex, AIDS See AIDS dementia complex.

dementia, MELAS See MELAS syndrome.

dementia Significant loss of intellectual abilities, such as memory capacity, that is severe enough to interfere with social or occupational functioning. Criteria for the diagnosis of dementia include impairment of attention, orientation, memory, judgment, language, motor and spatial skills, and function. By definition, dementia is not due to major depression or schizophrenia. Alzheimer’s disease is…

deltoid The muscle, roughly triangular in shape, that stretches from the collarbone (clavicle) over the shoulder to the upper bone of the arm (humerus). It contracts to move the arm up from the side.

delta-storage pool disease See HermanskyPudlak syndrome.

delta cell, pancreatic A type of cell located in tissue that is called the islets of Langerhans in the pancreas. Delta cells make somatostatin, a hormone that inhibits the release of numerous hormones in the body.

delivery, vertex See vertex birth.

delivery, footling See footling birth.

delivery, breech See breech birth.