| lymphoid ring | The broken ring of lymphoid tissue, formed of the lingual, faucial, and pharyngeal tonsils. Synonym: Bickel's ring, tonsillar ring, Waldeyer's throat ring. (05 Mar 2000) |
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| lymphoid series | The cells at various states in the development in lymphoid tissue of the mature lymphocytes, e.g., lymphoblasts, young lymphocytes, mature lymphocytes. (05 Mar 2000) |
| 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) |
| calcific nodular aortic stenosis | Most common type of aortic stenosis, occurring usually in elderly men, in which the cusps contain calcified fibrous nodules on both surfaces; the causes include rheumatic fever, atherosclerosis, age-related degeneration, and congenitally bicuspid aortic valve. (05 Mar 2000) |
| panniculitis, nodular nonsuppurative | A form of panniculitis characterised by recurrent episodes of fever accompanied by the eruption of single or multiple erythematous subcutaneous nodules on the lower extremities. They normally resolve, but tend to leave depressions in the skin. The condition is most often seen in women, alone or in association with other disorders. (12 Dec 1998) |
| goiter, nodular | An enlarged thyroid gland containing circumscribed nodules within its substance. (12 Dec 1998) |
| Salzmann's nodular corneal degeneration | Large and prominent nodules of a solid, opaque material that stands out from the surface of the cornea; occurs occasionally in persons previously affected by phlyctenular keratitis. (05 Mar 2000) |
| nodular | Bumpy. (12 Dec 1998) |
| nodular amyloidosis | A localised form of amyloidosis in which amyloid occurs as masses or nodules beneath the skin or mucous membranes, e.g., in the larynx. Synonym: amyloid tumour, focal amyloidosis. (05 Mar 2000) |
| nodular arteriosclerosis | Atheromas occurring in the arterial intima as discrete tumours. (05 Mar 2000) |
| nodular body | In fungi, a compact, roughly spherical or squarish structure formed by coiling and twisting of the end of a hypha; considered to be abortive growths toward sexual reproduction. (05 Mar 2000) |
| nodular disease | Oesophagostomiasis in herbivores and primates, characterised by nodules in the wall of the large intestine, caecum, and occasionally, the ileum; the nodules are filled with caseous material and result from host response to encystment of the larvae of Oesophagostomum species. (05 Mar 2000) |
| nodular episcleritis | Episcleritis with localised inflammation foci in episcleral tissues. (05 Mar 2000) |
| nodular fasciitis | A rapidly-growing tumour-like proliferation of fibroblasts, not thought to be neoplastic, with mild inflammatory exudation occurring in fascia; the fibrosis may infiltrate surrounding tissue but does not progress indefinitely or metastasize. Synonym: pseudosarcomatous fasciitis. (05 Mar 2000) |