| secondary 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) |
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| hyaline degeneration of the elastic tissue of the arterial wall | Seen during involution of the uterus. (05 Mar 2000) |
| skeletal muscle tissue | <anatomy, pathology> A rather non-specific term usually applied to the striated muscle of vertebrates that is under voluntary control. The muscle fibres are syncytial and contain myofibrils, tandem arrays of sarcomeres. (18 Nov 1997) |
| skin and connective tissue diseases | A collective term for diseases of the skin and its appendages and of connective tissue. (12 Dec 1998) |
| smooth muscle tissue | <anatomy, pathology, physiology> Muscle tissue in vertebrates made up from long tapering cells that may be anything from 20-500m long. Smooth muscle is generally involuntary and differs from striated muscle in the much higher actin/myosin ratio, the absence of conspicuous sarcomeres and the ability to contract to a much smaller fraction of its resting length. Smooth muscle cells are found particularly in blood vessel walls, surrounding the intestine (particularly the gizzard in birds) and in the uterus. The contractile system and its control resemble those of motile tissue cells (e.g. Fibroblasts, leucocytes) and antibodies against smooth muscle myosin will cross react with myosin from tissue cells, whereas antibodies against skeletal muscle myosin will not. See: dense bodies. (18 Nov 1997) |
| soft tissue infections | Infections of non-skeletal tissue, i.e., exclusive of bone, ligaments, cartilage, and fibrous tissue. The concept is usually referred to as skin and soft tissue infections and usually subcutaneous and muscle tissue are involved. The predisposing factors in anaerobic infections are trauma, ischemia, and surgery. The organisms often derive from the faecal or oral flora, particularly in wounds associated with intestinal surgery, decubitus ulcer, and human bites. (12 Dec 1998) |
| soft tissue injuries | Injuries of tissue other than bone. The concept is usually general and does not customarily refer to internal organs or viscera. It is meaningful with reference to regions or organs where soft tissue (muscle, fat, skin) should be differentiated from bones or bone tissue, as "soft tissue injuries of the hand". (12 Dec 1998) |
| soft tissue sarcoma | A sarcoma that begins in the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body. Not a type of bone cancer. (12 Dec 1998) |
| soft tissue window | mediastinal window |
| nasion soft tissue | The outer point of intersection between the nasion-sella line and the soft tissue profile. (05 Mar 2000) |
| nephrogenic tissue | The tissue from which the pronephros, mesonephros, and metanephros develop. (05 Mar 2000) |
| nerve tissue protein s 100 | Highly acidic calcium-binding protein found in large concentration in the brain and believed to be glial in origin; also found in other organs in the body. (12 Dec 1998) |
| nervous tissue | A highly differentiated tissue composed of nerve cells, nerve fibres, dendrites, and a supporting tissue (neuroglia). (05 Mar 2000) |
| subcutaneous tissue | The soft tissue immediately underlying the skin or epidermis. (27 Sep 1997) |
| nodal tissue | See: atrioventricular node, sinuatrial node. (05 Mar 2000) |