PATH 300 Lecture Notes - Lecture 9: Innate Immune System, Adaptive Immune System, Fibrin

• School: McGill University
• Department: Pathology
• Course: PATH 300
• Professor: Edith Zorychta

Document Summary

3 different failures of the immune system: hypersensitivity (overactive immune response) no longer protective; causes tissue damage, autoimmunity (recognition of self-antigens) Include epithelial barriers, phagocytes, dendritic cells, complement, nk cells. Acts specifically to specific sequences on microbes and pathogens. Apcs t-lymphocytes effector t cells. Cardinal signs of inflammation include heat, redness, swelling, pain: these eventually lead to loss of function. Example: cutting your finger: must stop the bleeding blood clotting system = platelets, platelets become activated and temporarily block leakage from blood vessels, platelets alone are not sufficient. They need fibrin strands to form a clotting cascade. Clotting cascade will lead to the production of thrombin, which will cleave fibrinogen into monomers which assemble into fibrin (insoluble). Non-cellular defense systems are interconnected and include: coagulation cascade. Involves proteolytic cleavages which results in end-products that have important functions in driving the immune response: one of the downstream effects of this cascade is formation of membrane attack complexes (mac).