| cell matrix | A fluid cytoplasmic substance filling the interstices of the cytoskeleton. Synonym: cell matrix, cytomatrix. (05 Mar 2000) |
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| cell-mediated immunity | <immunology> Immune response that involves effector T lymphocytes and not the production of humoral antibody. Responsible for allograft rejection, delayed hypersensitivity and in defence against viral infection and intracellular protozoan parasites. (26 Mar 1998) |
| cell-mediated reaction | Immunological reaction of the delayed type, involving chiefly T lymphocytes, important in host defense against infection, in autoimmune diseases, and in transplant rejection. See: skin test. (05 Mar 2000) |
| cell membrane | <cell biology> The structure enveloping a cell, enclosing the cytoplasm and forming a selective permeability barrier. It consists of lipids, proteins and some carbohydrates, the lipids thought to form a bilayer in which integral proteins are embedded to varying degrees. Synonym: plasma membrane. (26 Mar 1998) |
| cell membrane permeability | A quality of cell membranes which permits the passage of solvents and solutes into and out of cells. (12 Dec 1998) |
| cell migration | <cell biology> Implies movement of a population of cells from one place to another as in the movement of neural crest cells during morphogenesis. (26 Mar 1998) |
| cell migration inhibition | Phenomenon of cell-mediated immunity measured by in vitro inhibition of the migration or phagocytosis of antigen-stimulated leukocytes or macrophages. Specific assays have been developed to estimate levels of migration-inhibitory factor, immune reactivity against tumour-associated antigens, and immunosuppressive effects of infectious microorganisms. (12 Dec 1998) |
| cell movement | <cell biology> A more general term than locomotion, that can include shape change, cytoplasmic streaming etc. (26 Mar 1998) |
| cell nucleolus | Within most types of eukaryotic cell nucleus, a distinct region, not delimited by a membrane, in which some species of rrna (RNA, ribosomal) are synthesised and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rrna is transcribed from a nucleolar organiser, i.e., a group of tandemly repeated chromosomal genes which encode rrna and which are transcribed by RNA polymerase I. (12 Dec 1998) |
| cell nucleus | Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. (12 Dec 1998) |
| P cell | A characteristic specialised cell, with probable pacemaker function, found in the S-A node and A-V junction. (05 Mar 2000) |
| cell organelle | <cell biology> A structurally discrete component of a cell. (18 Nov 1997) |
| cell physiology | Characteristics and physiological processes of cells from cell division to cell death. (12 Dec 1998) |
| cell plate | <plant biology> Region in which the new cell wall forms after the division of a plant cell. In the plane of the equator of the spindle a disc like structure, the phragmoplast forms, into which are inserted pole derived microtubules. Golgi derived vesicles containing pectin come together and fuse at the plate which develops from the centre outwards and eventually fuses with the plasma membrane thereby separating the daughter cells. (26 Mar 1998) |
| cell polarity | 1. <cell biology> In epithelial cells the differentiation of apical and basal specialisations. In many epithelia the apical and baso lateral regions of plasma membrane differ in lipid and protein composition and are isolated from one another by tight junctions. The apical membrane may, for example: be the only region where secretory vesicles fuse or have a particular ionic pumping system. 2. A motile cell must have some internal polarity in order to move in one direction at a time: a region in which protrusion will occur (the front) must be defined. Locomotory polarity may be associated with the pericentriolar microtubule organising centre and can be perturbed by drugs that interfere with microtubule dynamics. (26 Mar 1998) |