Unit Three Textbook Notes - Unit Three Textbook Notes...

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Unit Three Textbook Notes Chapter Fourteen: Innate Immune Response First-Line Defenses: prevent entry, sensory systems detect invasion, and effector mechanisms destroy and remove the invader o Physical Barriers: skin is composed of two main layers dermis and epidermis Mucous membranes are constantly bathed with mucus and other secretions that help wash microbes from the surfaces o Antimicrobial Substances: lysozyme, peroxidase enzymes, lactoferrin, and defensins inhibit or kill microorganisms o Normal Microbiota (Flora): competitively exclude pathogens and stimulate the host defenses Cells of the Immune System: o Granulocytes: include neutrophils, basophils, and eosinophils o Mononuclear Phagocytes: Monocytes: circulate in the blood Dendritic Cells: develop from monocytes while some have other origins Macrophages: located in tissues o Lymphocytes: include B Cells, T Cells, and Natural Killer (NK) Cells Involved in adaptive immunity Cell Communication: o Cells have Pattern Recognition Receptors (PRRs) that recognize invaders Toll-Like Receptors (TLRs): allow sentinel cells to detect extracellular molecules that signify the presence of microbes NOD-Like Receptors (NLRs): allow cells to detect internal invaders or cell damage RIG-Like Receptors (RLRs): allow cells to detect viral nucleic acid Virally infected cells respond by making interferons, causing nearby cells to prepare to undergo apoptosis if they become infected with a virus o Surface Receptors: bind ligands, allowing the cell to detect substances o Cytokines: include chemokines, colony-stimulating factors (CSFs), interferons (IFNs), interleukins (ILs), and tumor necrosis factor (TNF) o Adhesion Molecules: allow cells to adhere to other cells Complement System: activated in response to certain invaders, detects microbial cells and antibodies bound to antigens activated in response o Major protective outcomes of complement system activation include Opsonization , inflammatory response, and lysis of foreign cells o Complement regulatory proteins prevent host cell surfaces from activating the complement system via the alternative pathway Phagocytosis: steps include chemotaxis, recognition and attachment, engulfment, phagosome maturation, and phagolysosome formation, destruction and digestion, and exocytosis o Macrophages: always present in tissues to some extent but can call in reinforcements when needed Can become an activated macrophage Macrophages, giant cells, and T Cells form Granulomas that wall off and retain material that cannot be destroyed o Neutrophils: first cell type recruited from the bloodstream to the site of damage Inflammatory Response: involves many components of innate immunity, including phagocytes o Swelling, redness, heat, and pain are the signs of inflammation body’s attempt to contain a site of damage, localize the response, eliminate the invader, and restore tissue function

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