PNB 2265 Lecture 18: Defense 1
13 Mar 2017
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Document Summary
Non-speci c (innate) v speci c (adaptive: bank walls (keep robbers out) v surveillance camera (identify speci c robber) Role of immune responses: defend against infection by microbes, immune surveillance, eliminate damaged cells, negative aspect -> allergies, autoimmune diseases, transplant rejection. Capillaries are blind ended: lymphoid tissues/organs. Secondary -> lymph nodes, spleen, peyer"s patches, tonsils: functions: Found in connective tissue under epithelium of respiratory, digestive, urinary tracts. Myeloid stem cells -> all cell types except lymphocytes. Lymphoid stem cells -> t and b lymphocytes. Other cells derived from white blood cells: macrophages -> phagocytosis, mast cells -> histamine. Dendritic cells: highly motile, not macrophages but can phagocytose, found in almost all tissues. Especially ports of entry where external and internal environment meets. Nonspeci c defenses: no speci c recognition of identity of foreign cell/matter, same response regardless of stimulus, prevention rst. First line : physical/chemical barriers, skin and mucous membranes -> physical barrier, variety of protective chemicals.
