| expression system | <molecular biology> Combination of an expression vector, its cloned DNA, and the host for the vector that provide a context to allow foreign gene function in a host cell, that is, produce proteins at a high level. (13 Nov 1997) |
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| exterofective system | Name applied by Cannon to the somatic nervous system as opposed to the interofective or autonomic system. (05 Mar 2000) |
| extrapyramidal motor system | Literally: all of the brain structures affecting bodily (somatic) movement, excluding the motor neurons, the motor cortex, and the pyramidal (corticobulbar and corticospinal) tract. Despite its very wide literal connotation, the term is commonly used to denote in particular the striate body (basal ganglia), its associated structures (substantia nigra; subthalamic nucleus), and its descending connections with the midbrain. (05 Mar 2000) |
| extrapyramidal motor system disease | A general term for a number of disorders caused by abnormalities of the basal ganglia or certain brain stem or thalamic nuclei; characterised by motor deficits, loss of postural reflexes, bradykinesia, tremor, rigidity, and various involuntary movements. Synonym: extrapyramidal motor system disease. (05 Mar 2000) |
| kallikrein-kinin system | A system produced in the distal nephron of the kidney. Its components are kallikrein, kinins, kininase I and II, and enkephalinase. It is involved in mediation and modulation of the renin-angiotensin-aldosterone system, prostaglandins, vasopressins, and in the regulation of sodium-water balance, renal haemodynamics, and particularly blood pressure. The system participates in the control of renal functions and the physiopathology of renal diseases. (12 Dec 1998) |
| kallikrein system | A blood serum system, the activity of which is initiated by factor XII (Hageman factor) leading to the production of prekallikrein activator and then to kallikrein which, after activation by plasmin, splits bradykinin from kininogen. (05 Mar 2000) |
| kidd blood-group system | A group of antigens consisting principally of jk(a) and jk(b), determined by allelic genes. Amorphs are encountered. Antibodies of these substances are usually weak and quite labile, stimulated by erythrocytes. (12 Dec 1998) |
| Zaffaroni system | A chromatographic system for the separation of steroids. (05 Mar 2000) |
| unified medical language system | A research and development program initiated by the national library of medicine to build an intelligent automated system that can understand biomedical concepts, words, and expressions and their interrelationships, and use this understanding to help users retrieve and organise information from a variety of machine-readable sources. The goal of the umls is to compensate for differences in the terminology of the disparate systems and for variations in user modes of expression. The umls project has produced four knowledge sources meant to be used by user interface programs. These are the metathesaurus, the semantic network, the information sources map, and the specialist lexicon. (12 Dec 1998) |
| kinetic system | A term proposed by G.W. Crile to denote the chain of organs through which latent energy is transformed into motion and heat: it includes the brain, the thyroid, the adrenals, the liver, the pancreas, and the muscles, that part of the neuromuscular system whereby active movements are effected; distinguished from the static system. (05 Mar 2000) |
| feedback system | A complex of neuronal circuits whereby a part of the efferent path returns to the input to modulate its activity, thus acting as a governor on the system. See: feedback. (05 Mar 2000) |
| urinary system | The organs concerned in the production and excretion of urine, together with the organs of reproduction. (12 Dec 1998) |
| urogenital system | The organs concerned in the production and excretion of urine, together with the organs of reproduction. (12 Dec 1998) |
| uropoietic system | The kidneys, ureters, bladder, and urethra, considered as a system for the secretion and excretion of urine. (05 Mar 2000) |
| filling defect in renal collecting system | <radiology> Common causes: transitional cell carcinoma, blood clot, lucent calculus (urate) less common causes: fungus ball, sloughed papilla, fibroepithelial polyp, invasion by hypernephroma, malakoplakia, vessel impression, metastases (12 Dec 1998) |