ANFS332 Lecture Notes - Lecture 19: Clonal Selection, Antigen, Macrophage
4 Feb 2020
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Immunology iii - primary and secondary lymphoid tissues, antigen, antibody kinetics. Bone marrow all blood cells arise from pluripotent stem cells in bone marrow. It is also the site of b cell maturation. B cells that do not form functional antibodies or that make antibodies against self die (80%) by apoptosis. In birds b cell maturation occurs in a specialized organ the bursa of fabricius. A flat bilobed organ located above the heart and below the thyroid. Within the lobes are lobules consisting of dendritic cells, epithelial cells and macrophages. The thymus is largest at puberty and shrinks thereafter. Precursor t cells enter via they blood and mature into mature lymphocytes. again, most cells (recognizing self antigens) die by apoptosis! Lymphoid tissues are part of the lymphatic system. The organs/ducts/nodes of the lymphatic system transfer a clear fluid lymph. The lymphatic system is not closed (unlike the circulatory system) and has no central pump (no heart)
