MCB 3020C Lecture Notes - Lecture 29: Adaptive Immune System, Innate Immune System, White Blood Cell
Document Summary
Immunity is the ability of an organism resist infection. Innate immunity (nonspecific immunity: the noninducible ability to recognize and destroy an individual pathogen or its products, does not require previous exposure to a pathogen or its products. Infection site and tissue specificity: different pathogens invade different tissues, routes of infection are crucial (tetanus is in wounds, while salmonella is ingested, not vice versa) Physical and chemical barriers to infection: mucosal membranes are coated with a thick layer of mucus, stomach acid inhibits bacterial growth, skin is salty and acidic, limiting bacterial growth. The lymphatic system is a separate circulatory system that drains lymph fluid from extravascular tissues. Blood is pumped through arteries and capillaries and returns from the body through veins. In capillary beds, leukocytes and solutes pass from blood into the lymphatic system. Lymph nodes contain high concentrations of lymphocytes and phagocytes. Whole blood is composed of plasma and cells: plasma contains proteins and other solutes.
