Power point 1: The immune systemObjective 1. Define the immune system and its 3 lines of defense. The immune system is a functional system made up of two intrinsic defense systems that act independently and cooperatively to provide resistance to disease. Innate (nonspecific) defense system: 1st line of defense: external membranes, skin & mucosa2nd line of defense: takes effect when the 1st has been penetrated. Inflammation – protein, phagocytesAdaptive (specific) defense system:3rd line of defense: attacks foreign substances, takes longer than the innate system to work. Objective 2 Explain how the innate and adaptive systems are intertwinedThey are intertwined because proteins released during an innate response alerts cells of the adaptive system about the presence of a foreign substance. Basically the innate system sets the adaptive system up to be effective.Objective 3. What are surface barriers and how do they function as the first line of defense?Surface barriers are skin, mucous membranes, & their secretions (this isthe 1st line of defense). Keratin in the skin hardens it and provides a tough barrier as the first line of defense. Mucous membrane provides the lining for all body cavities and serves as physical barriers and also secretes protective chemicals such as acidity of skin secretions pH 3-5 which inhibit bacterial growth, stomach mucosa secretes HCl and protein-digesting enzymes to kill microorganisms, saliva and lacrimal fluid contain lysozymes which destroy bacteria, mucus to trap microorganisms when they try to enter openings. Furthermore, the skin is resistant to weak acids, weak bases, and toxins. Objective 4. Explain Nonspecific Cellular & ChemicalDefense; the second line of defense including: phagocytes, phagocytosis, phagocyte mobilization, and other factors in this line.Phagocytes: confront pathogens. Include:Macrophages: leave the bloodstream in search of foreign substancesNeutrophils: type of white blood cell that becomes phagocytic upon an encounter.- both derive from white blood cellsNatural killer cells: located in blood and lymph. Defensive cells that can kill infected cells without activating the adaptive immune system. Secrete chemicals that enhance the inflammatory response. Stimulate apoptosis of infected cells (cell death). First, they determine the lack of cell-surface receptors. Then, determine certain cell surface sugars. Phagocytosis: Phagocyte adheres to a microbe and plasmic extensions bind to the particle and pull it inside a membrane-lined vacuole and it becomes a phagosome. Phagosome fuses with a lysosome to form a phagolysosome. The microbe is then killed and digested by lysosomal enzymes leaving a residual body. The residual material is removed from the phagocyte by exocytosis. Adherence is made possible by recognizing the pathogen with the help of complementary proteins. Pathogen destruction: simple digestion by lysosomal enzymes. Respiratory burst- free radicals, which kill cells. K+ enters phagosome, pH rises, activates protein-digesting enzymes that digest the invader. Defensins are chemicals produced by neutrophils that pierce the pathogen membranePhagocyte Mobilization: Leukocytosis- damaged cells include release of neutrophils from red bone marrow to increase WBCs in blood. Margination- Clinging of phagocytes to inner walls of capillaries. Diapedesis- chemical signaling allows neutrophils to squeeze through capillary walls. Chemotaxis-inflammatory chemicals which act as magnets to draw in phagocytes(neutrophils and monocytes)Objective 5. Describe the responses to injury, reactive hyperemia, and the mechanisms of occlusion training.Injury: release of chemical mediators such as cytokines, histamine, kinins, prostaglandins, leukotienes and complement will induce vasodilation of small blood vessels in the injured area. Chemicals also increase permeability of capillaries exudates accumulate (fluid with clotting factors and antibodies) which causes swelling, pressure on nerves causes pain. Inflammation sets the stage for repair. Hyperemia: more blood flow accounts for redness and heatOcculusion: results in reactive hyperemia (mediated vasodilation). Mechanisms: fiber type recruitment, accumulation of metabolites(lactate, GH), mTOR activation (protein synthesis pathway)Objective 6. Describe Antimicrobial Proteins.Antimicrobial Proteins: enhance the innate defenses by attacking microorganisms/not allowing reproduction.Complement proteins: group of proteins that normally circulate in the blood in an active state. Amplifies the inflammatory process (through vasodilation) and causes cell lysis of certain bacteria and other call types. Enhances the effectiveness of innate and adaptive defenses. Interferon: secreted by virus-infected cells. Stimulate the productionof proteins that will interfere with viral replication in healthy cells. Help protect cells that haven’t been infected.Gamma – secreted by lymphocytes, enhances T cell activity. Treats chronic granulomatous disease (abnormal wbcS)Alpha – secreted by most leukocytes (except lymphocytes) reduce inflammation. Treats genital warts and hepatitis CBeta – secreted by fibroblasts, reduce inflammation. Treat MSClassical and alternative pathways of activation: Viruses damage the body by invading tissue cells and taking over the cellular metabolicmachinery to reproduce themselves.Objective 7. Describe two biochemical pathways activate the complement system.The classical pathway: involves the binding of antibodies to the invadingorganisms and the subsequent binding of C1 to the antigen-antibody complexesThe alternative pathway: factors B,D and p interact with polysaccharide molecules on the surface of certain microorganisms. The 2 converge on C3 and cleave it into C3a and C3b. C3b binds to the target cell’s surface and will trigger the insertion of MAC which will form and stabilize a holein the membrane causing lysis via an influx of water. C3b will coat the microorganism allowing neutrophils and macrophages to engulf and destroy more rapidly. C3a will amplify the inflammatory response. C-reactive protein passes acute infection of inflammation by binding to certain surface molecules of pathogens and damaged body cells, targeting them for disposal by phagocytes and complement, and also binds C1 to activate complementObjective 8. Describe the adaptive defense system and its responses (i.e. fever).Adaptive defense system: antigen specific, systemic (immunity is not restricted to the
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