| fibrous tissue | Although most connective tissue has fibrillar elements, the term usually refers to tissue laid down at a wound site well vascularised at first (granulation tissue) but later avascular and dominated by collagen rich extracellular matrix, forming a scar. Excessive contraction and hyperplasia leads to formation of a keloid. (18 Nov 1997) |
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| foetal tissue transplantation | Transference of foetal tissue between individuals of the same species or between individuals of different species. (12 Dec 1998) |
| lymphatic tissue | A structure found within the lymphatic system that consists of lymphocytes within a network of fibres. (09 Oct 1997) |
| lymphoid tissue | <anatomy> Tissue that is particularly rich in lymphocytes (and accessory cells such as macrophages and reticular cells), particularly the lymph nodes, spleen, thymus, Peyer's patches, pharyngeal tonsils, adenoids and (in birds) the Bursa of Fabricius. Central lymphoid tissue: A term occasionally used as synonym for primary lymphoid tissue but should be avoided to prevent confusion between anatomical location, which is irrelevant and centrality in the system. Peripheral lymphoid tissue: Secondary lymphoid tissue, not necessarily located peripherally. Primary lymphoid tissue: Lymphoid tissues in which immune cells develop as opposed to the secondary or peripheral lymphoid tissues in which antigen independent or antigen dependent stages of maturation take place and in which responsive lymphocytes are found. Primary lymphoid tissues are foetal liver, adult bone marrow and thymus (and Bursa of Fabricius in birds). Secondary tissues are lymph nodes, spleen, tonsils and mucosa associated lymphoid tissue. (20 Mar 1998) |
| lymphoma, mucosa-associated lymphoid tissue | Extranodal lymphoma of lymphoid tissue associated with mucosa that is in contact with exogenous antigens. Many of the sites of these lymphomas, such as the stomach, salivary gland, and thyroid, are normally devoid of lymphoid tissue. They acquire malt tissue as a result of an immunologically mediated disorder. (12 Dec 1998) |
| absorptive cells of intestine | Cell's on the surface of villi of the small intestine and the luminal surface of the large intestine that are characterised by having microvilli on their free surface. (05 Mar 2000) |
| air cells | Air-containing spaces in the skull. See: pulmonary alveolus. (05 Mar 2000) |
| air cells of auditory tube | Occasional small air cells in the inferior wall of the auditory tube, near the tympanic orifice, communicating with the tympanic cavity. Synonym: cellulae pneumaticae tubae auditivae, air cells of auditory tube. (05 Mar 2000) |
| Alpha cells | Alpha cell's of pancreas or of anterior lobe of hypophysis. (05 Mar 2000) |
| alpha cells of anterior lobe of hypophysis | Acidophil cell's that constitute about 35% of the cell's of the anterior lobe. There are two varieties: one that elaborates somatotropin, another that elaborates prolactin. (05 Mar 2000) |
| alpha cells of pancreas | Cell's of the islets of Langerhans that secrete glucagon. (05 Mar 2000) |
| amniogenic cells | Cell's from which the amnion develops. (05 Mar 2000) |
| anabiotic cells | Cell's that are capable of resuscitation after apparent death; the existence of anabiotic tumour cell's is postulated to explain the recurrence of a cancer after a very long symptomless period following operation. (05 Mar 2000) |
| angioblastic cells | Those cell's in the early embryo from which primitive blood cell's and endothelium develop. (05 Mar 2000) |
| anterior cells | The anterior group of air cells of the ethmoidal sinus's; each sinus communicates with the middle meatus of the nasal cavity. Synonym: sinus ethmoidales anteriores, anterior cells, anterior sinuses, cellulae anteriores. (05 Mar 2000) |