Power point 1 The immune system Objective 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 mucosa 2nd line of defense takes effect when the 1st has been penetrated Inflammation protein phagocytes Adaptive 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 intertwined They 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 is the 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 Chemical Defense 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 substances Neutrophils type of white blood cell that becomes phagocytic upon an encounter both derive from white blood cells Natural 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 membrane Phagocyte 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 heat Occulusion 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 production of 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 C Beta secreted by fibroblasts reduce inflammation Treat MS Classical and alternative pathways of activation Viruses damage the body by invading tissue cells and taking over the cellular metabolic machinery to reproduce themselves Objective 7 Describe two biochemical pathways activate the complement system The classical pathway involves the binding of antibodies to the invading organisms and the subsequent binding of C1 to the antigen antibody complexes The 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 hole in 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 complement Objective 8 Describe the adaptive defense system and its responses i e fever Adaptive defense system antigen specific systemic immunity is not restricted to the intial infection site protects us from a variety of diseases it has memory after intial exposure and it recognizes and mounts even stronger attacks
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