Figure 43.1 An overview of the body's defenses Chapter 43 Immune System Figure 43.1 An overview of the body's defenses Traps microbes Lymphocytes – Antibodies - proteins that attack - edema (swelling) - B cells T cells Ex. Lysozyme - protective protein Found: Opeing around eyes (tears, mucus) redness upper respiratory tract pain antigens (foreign molecules) blood flow Ex. Interferons - secreted by virus infected Bells, causes other cells to produce chemicals to inhibit viral reproduction

Figure 43.4 The human lymphatic system - - location where returns fluid from interstitial spaces lymphocytes develop T cells B cells Leukocytes – any white blood cell B cells T cells Macrophages Monocytes

Figure 43.5 A simplified view of the inflammatory response triggers inflamation Injured cells release chemicals: 1. Histamine - causes dilation of ________________ and increases permeability of _______________ 2. Prostaglandins - also ________________________________________________________ Fever can also result from infections - moderate fever helps with defense by _______________________________________________ - - increase body reactions for ___________________________ * septic shock - caused by a large systemic inflammatory response blood vessels capillaries promotes blood flow inhibiting growth of microorganisms facilitates phagocytosis repair high fever low blood pressure

Figure 43.6 Clonal selection Antigens activate specific 2 types: 1. 2. B cells T cells foreign Different receptors on B cells - Membrane antibodies also called only one receptor fits the antigens shape membrane immunoglobulins Ex. Occurs due to: virus bacteria fungi protozoa parasitic worms pollen Clone of B cells Clone of B cells can either develop into: memory cells clone plasma cells effector cells Short lived plasma cells, also called Secrete Specific Long lived cells: can respond quickly to the next to the same antibodies to the antigen

Figure 43.7 Immunological memory Primary immune response Responsible for initiating a • Effector plasma cells •Effector B cells Memory cells proliferate at: secondary immune response initial exposure and second exposure (make antibodies) T cell response

Figure 43.8 The development of lymphocytes white blood cells Lymphocytes are Two types: T cells (develop in thymus) B cells (develop in bone marrow) Found: B cells and T cells must distinguish self from nonself, if not: - autoimmune diseases, have no self tolerance Both B and T cells have specific antigen receptors Develops in: Develops in:

Figure 43.9 The interaction of T cells with MHC molecules Antigen presenting cell: APC Found on: Found on: - macrophages - B cells - T cells - inside thymus almost every cell in the body Major histocompatibility complex - distinguishes self from non-self identifies abnormal cells

Figure 43.10 An overview of the immune responses Involves B cell activation with the production of antibodies Defends against: Involves cytotoxic T cell activation Defends against: 1. cells infected by virus or bacteria 2. fungi 3. protozoa 4. parasitic worms responds to transplants and cancer cells 1. free bacteria 2. toxins 3. viruses in body fluids

Figure 43.11 The central role of helper T cells: a closer look protein antigen presenting cell other lymphocytes Cytokines - proteins that stimulate ex. interleukin 1, interleukin 2 1. APC engulfs bacteria, transports to ______________________________________________ 2. A specific TH cell binds to the __________________________________________________ interleukin-1 secreted by the __________________________________________________ 3. TH cell proliferates into more___________________________________________________ other cytokines and interleukin-2 are secreted 4. Cytokines stimulate __________________________________________________________ the surface using a class II MHC molecule MHC antigen complex APC enhances TH cells to secrete interleukin-2 TH cells and memory T cells TH cells and activates B cells and TC cells

Figure 43.12a The functioning of cytotoxic T cells antigen using a class I MHC molecule 1. Infected cells displays _______________________________________________________ TC cell binds to the __________________________________________ 2. TC cell releases ______________ creates pores in the membrane of the infected _______ 3. Water and ions flow _________________________ ________________________ MHC antigen complex perforin cell into infected cell cell lysis

Figure 43.13 Humoral response to a T-dependent antigen

Figure 43.14 Epitopes (antigenic determinants) Antibodies - a group of proteins called immunoglobulins disease or vaccination Active immunity - immunity from an infectious _________________________________________ Passive immunity - mother to fetus through the __________________ passes __________________ also through ________________________________ Blood type: type A blood contains _______ antigens type B blood contains _______ anitgens type AB blood contains _______ antigens type O blood contains _______ antigens Rh factor can cause fetus RBC’s to be destroyed placenta antibodies breast milk A antibodies *blood contains _______________ to fight ____________________ after a transfusion B antigens A, B no

Figure 43.16 Effector mechanisms of humoral immunity

Figure 43.20 The stages of HIV infection