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Animal Form & Function Immune System. AP Biology. Nonspecific Defenses. Do not discriminate Present at birth Prevent approach of pathogens. Nonspecific Defenses. Physical barriers Skin Creates effective barrier Multiple layers Keratin Desmosomes. Nonspecific Defenses.
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Animal Form & FunctionImmune System AP Biology
Nonspecific Defenses • Do not discriminate • Present at birth • Prevent approach of pathogens
Nonspecific Defenses • Physical barriers • Skin • Creates effective barrier • Multiple layers • Keratin • Desmosomes
Nonspecific Defenses • Physical barriers • Secretions • Oil, sweat, mucus • Wash away pathogens • Lysozyme kills bacteria
Nonspecific Defenses • Phagocytes • Neutrophils • Phagocytize cellular debris & invading bacteria
Nonspecific Defenses • Phagocytes • Eosinophils • Target foreign compounds or pathogens coated with antibodies
Nonspecific Defenses • Phagocytes • Macrophage • Derived from monocytes • Large
Nonspecific Defenses • Phagocytes • NK cells • Natural killer cells • Large lymphocytes • Destroy abnormal cells • Constantly monitor normal tissues
Nonspecific Defenses • Inflammatory response • Histamine released by basophils • Blood vessels dilate • Increased blood flow to damaged area • Phagocytes mobilized • Complement activated • 20 proteins • React in chain reaction • Attacks & breaks down cell walls
Specific Defenses • Target specific antigen • Involves lymphocytes • Remembers antigens encountered in the past • Ignores self and attacks nonself
Specific Defenses • Cell-Mediated Immunity • Provides defense against abnormal cells & pathogens inside living cells • Involves T cells (green cell)
Specific Defenses • Cell-Mediated Immunity • Antigen engulfed by macrophage • Antigen broken down • Macrophage presents pieces of antigen on cell membrane • Specific T cell binds to antigen pieces • Specific T cell activated
Specific Defenses • Cell-Mediated Immunity • Activated T cell divides & differentiates • Helper T cells – stimulate immune response • Cytotoxic T cells – killer T cells • Memory T cells – remember encountered antigens; activated with 2nd exposure • Supressor T cells – slows things down
Specific Defenses • Antibody-Mediated Immunity (Humoral Response) • Provides defense against antigens & pathogens in body fluids • Involves B cells
Specific Defenses • Antibody-Mediated Immunity
Specific Defenses • Antibody-Mediated Immunity • Specific B cell activated • Activated B cell divides & differentiates • Plasma cells • Produce antibodies • Memory B cells • Remember encountered antigens • Activated with 2nd exposure
Specific Defenses • Antibody-Mediated Immunity • Specific B cell activated • Activated B cell divides & differentiates • Plasma cells • Produce antibodies • Memory B cells • Remember encountered antigens • Activated with 2nd exposure
Specific Defenses • Primary Immune Response • Period I • B cell activated • Activated B cell divides & differentiates • Plasma cells produce antibodies
Specific Defenses • Secondary Immune Response • Period II • Memory B cell activated • Faster response • Strongerresponse • Less lag timeafter exposure