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IMMUNE SYSTEM. Immunity. Barrier Defenses. Integument Secretions Lysozymes Mucus. Internal Defenses. Phagocytic Leukocytes Neutrophils Suicidal engulfing of pathogens Macrophages Engulf multiple invaders Patrol or reside in spleen and lymph nodes. Internal Defenses.
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Barrier Defenses • Integument • Secretions • Lysozymes • Mucus
Internal Defenses • Phagocytic Leukocytes • Neutrophils • Suicidal engulfing of pathogens • Macrophages • Engulf multiple invaders • Patrol or reside in spleen and lymph nodes
Internal Defenses • Other leukocytes • Eosinophils • Bombard larger parasites w/ enzymes • Natural Killer Cells • Euthanize infected cells • Interferons • Inhibit viral reproduction
Internal Defenses • Inflammatory response • Chem signals released by invaders or damaged cells • Arterioles dilate, venules constrict • Redness, heat, edema (swelling) • Phagocytosis and clotting
Acquired Immunity • Lymphocytes • Diversity • Receptor proteins match different antigens • Replication (cloning) • Specific response to foreign material • Memory in case of future exposure Cell-mediated Humoral
Acquired Immunity Antigen-presenting cells Infected cell Macrophage “Look what attacked me!” “Look what I ate!” Lymphocyte “Rally the troops!”
Acquired Immunity • Lymphocytes • B cells • Mature in bone marrow • Humoral immunity • Fight pathogens with antibodies in fluids (blood, lymph, interstitial) • T cells • Mature in thymus • Cell-mediated immunity • Destroy infected cells to limit spread of disease Infected Cell Perforins
Immunity Review • What do basophils do? • What role do antigen presenting cells play in acquired immunity? • What’s the difference in how B cells and T cells fight infection?