I totally glazed over the lymphatic system last time I took A&PII. Really want to get it this time. It's interesting, but complement cascades and cytokines make me check out mentally. Had reservations about an online A&P class, but I'm actually learning so much more in this format. We do the labs in person and all the lecture is online. I get to academic shit post like this every week on the forum:
While our bodies have nonspecific innate defenses which react the same way every time foreign cells are encountered, adaptive immunity is the lymphatic system's approach to conflict escalation. As our former President Bush said once, "There's an old saying in Tennessee, I know it's in Texas, probably in Tennessee that says fool me once, shame on shame on you. You fool me you can't get fooled again." It is quite possible he was talking about adaptive immunity, a process governed by two types of lymphocytes: B cells and T cells. In adaptive immunity, the immune system "recognizes, reacts, and remembers" the foreign substance, "the 3 R's of immunity." The effect of which is a faster and stronger response to threats with subsequent exposures.
B cells originate in red bone marrow. Immature T cells also begin in red bone marrow, then move to the thymus to mature, and then go on to occupy lymphatic tissue. B cells are involved in antibody-mediated immunity and T cells are involved in cell-mediated immunity. Recognition of a foreign antigen stimulates an immune response where these cells multiply and circulate to lymphatic and infected tissue.
Antibody-mediated immunity:
B cells. Secrete antibodies. Provide protection to extracellular antigens (bacteria, viruses, parasites) and toxins.
Cell-mediated immunity:
T cells. Secrete cytokines. Provide protection to intracelluar antigens (bacteria, viruses, fungi) and tumors. Helper and supressor T cells regulate both antibody and cell-mediated immune responses. 4 types.
Helper T-cells: Activate B cells and cytotoxic T cells.
Memory T-cells: Responsible for secondary immune response.
Regulatory T-cells: Immune response control and suppression.
Cytotoxic T-cells: Directly kill foreign cells.
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