BIOL-K - Biology BIOL-K 338 Lecture 3: Tissues Notes
7 Feb 2017
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Lymphoid tissues: primary tissues: give rise to cells of the immune system, secondary tissues: provide organized sites for antigen capture and presentation to cells and for interaction between different cells of the immune system. Site of origin of all blood cells. Site of maturation of b cells (25% completely mature in bone marrow) Hematopoietic stem cells: less than 0. 005% cells in bone marrow. Blood cells in various stages of maturation. Stromal cells support growth and maturation of hematopoietic: thymus. Early t progenitor cells migrate from bone marrow to thymus. Most thymocytes die in thymus (only some mature to t-cells and move) Reaches max size during adolescence and shrinks (involutes) during aging. Leads to deficit of mature t cells and consequent immune deficiency (immune-deficient) Secondary lymphoid tissues: cells designed to expand, lymph nodes, spleen, mucosal-associated lymphoid tissues (malt), galt (gut associated lymphoid tissue), balt (bronchi associated lymphoid tissue, lymphadenopathy: swelling of lymph nodes.
