| mononuclear phagocyte system | A widely distributed collection of both free and fixed macrophages derived from bone marrow precursor cells by way of monocytes; their substantial phagocytic activity is mediated by immunoglobulin and the serum complement system. In both connective and lymphoid tissue, they may occur as free and fixed macrophages; in the sinusoids of the liver, as Kupffer cells; in the lung, as alveolar macrophages; and in the nervous system, as microglia. Synonym: system of macrophages. (05 Mar 2000) |
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| colloid system | A combination of the two phases, internal and external, of a colloid solution; the various system's are: gas + liquid (foam); gas + solid (meerschaum); liquid + gas (fog); solid + gas (smoke); solid + liquid (sol); liquid + solid (gel); liquid + liquid (emulsion); solid + solid (coloured glass). (05 Mar 2000) |
| pituitary-adrenal system | The interactions between the anterior pituitary and adrenal glands, in which corticotropin (acth) stimulates the adrenal cortex and adrenal cortical hormones suppress the production of corticotropin by the anterior pituitary. (12 Dec 1998) |
| combined system disease | A subacute or chronic disorder of the spinal cord, such as that occurring in certain patients with vitamin B12 deficiency, characterised by a slight to moderate degree of gliosis in association with spongiform degeneration of the posterior and lateral columns. Synonym: combined sclerosis, combined system disease, funicular myelitis, Putnam-Dana syndrome, vitamin B12 neuropathy. (05 Mar 2000) |
| motor system disease | <disease> Degenerative disease of unknown cause that affects predominantly motor neurons of spinal cord, cranial nerve nuclei and motor cortex. There is speculation that deficiency in ciliary neurotrophic factor may be involved. (18 Nov 1997) |
| complement system | A group of more than 20 serum proteins, some of which can be serially activated and participate in a cascade resulting in cell lysis. (05 Mar 2000) |
| conducting system of heart | The system of atypical cardiac muscle fibres comprising the sinoatrial node, internodal tracts, atrioventricular node and bundle, the bundle branches, and their terminal ramifications into the Purkinje network; sometimes also called cardionector. (05 Mar 2000) |
| multienzyme system | A group of related enzymes that operate in a particular metabolic pathway. (09 Oct 1997) |
| multiple system atrophy | A name grouping together the four cerebral degenerative diseases of olivopontocerebellar atrophy, shy-drager syndrome, striatonigral degeneration, and one form of parkinson disease, considering them different forms of the same disease process. (12 Dec 1998) |
| muscular system | All the muscles of the body collectively. (05 Mar 2000) |
| musculoskeletal system | All the muscles, bones, and cartilages of the body collectively. (12 Dec 1998) |
| point system test types | A near-vision test chart in which the various test types are multiples of a point (1/72 inch), lower-case letters being one-half the designated point size; reading 4-point at 16 inches is normal, and is designated N-4. (05 Mar 2000) |
| craniosacral system | parasympathetic part |
| portal system | A system of vessels in which blood, after passing through one capillary bed, is conveyed through a second set of capillaries before it returns to the systemic circulation. It pertains especially to the hepatic portal system. (12 Dec 1998) |
| haematopoietic system | The blood-making organs; in the embryo at different ages these are the yolk sac, liver, thymus, spleen, lymph nodes, and bone marrow; after birth they are principally the bone marrow, spleen, thymus, and lymph nodes. (05 Mar 2000) |