Budesa 1 A PII Objectives Exam 3 Power Point 1 The Immune System Objective 1 Define the immune system and its 3 lines of defense Functional system made up of two intrinsic defense systems that act independently and cooperatively to provide resistance to disease Innate nonspecific defense o Respond within minutes o 1st line External membranes skin mucosa o 2nd line Takes effect after 1st is penetrated Phagocytes fever NK cells antimicrobial proteins inflammation Adaptive specific defense o 3rd line o Attacks foreign substances o Takes longer than innate o Humoral immunity o Cellular immunity B cells Antibody mediated immunity Antibodies bind to bacteria and their toxins and free viruses Antibodies circulating freely in the blood and lymph bind to bacteria toxins to inactivate and allow phagocytes to act T cells Cell mediated immunity Lymphocytes attack virus or parasite infected tissue cells or cancer cells Direct kill pathogens themselves Indirect Amplify inflammation response allowing phagocytes to take out pathogen Objective 2 Explain how the innate and adaptive systems are intertwined Proteins released during an innate response alerts cells of the adaptive system about the presence of foreign substance Objective 3 What are surface barriers and how do they function as the first line of defense Skin keratinized epithelial membrane o Resistant to weak acids bases toxins Mucous membranes o Skin secretions pH 3 5 inhibits bacterial growth o Stomach mucosa secretes HCl and protein digesting enzymes to kill microorgasms o Saliva and lacrimal fluid contain lysozymes enzyme to destroy bacteria o Mucus to traps microorganisms trying to enter openings Budesa 2 Objective 4 Explain Nonspecific Cellular Chemical Defense the second line of defense including phagocytes phagocytosis phagocyte mobilization and other factors in this line Kill pathogens and repair tissues Phagocytes o Macrophages leave bloodstream in search of foreign substance o Neutrophils WBC that become phagocytic upon encounter o Both derive from WBC o Natural Killer Cells NK Located in blood lymph Defensive cells that can kill infected cells before the adaptive immune system is activated Including cancer Eliminate through direct contact by Determining lack of cell surface receptors Determining certain cell surface sugars Secrete chemicals that enhance the inflammatory response Stimulate apoptosis of target infected cell cell death o Inflammatory response Prevents spread of damaging agents to nearby tissues Disposes of cell debris and pathogens Sets stage for repair Redness heat swelling pain o Antimicrobial protein Complement protein Interferons o Fever o Phagocytosis Phagocyte adheres to microbe Plasmic extensions bind to particle and pull it inside membrane lined vacuole now called a phagosome Phagosome fuses with a lysosome contains digestive enzymes to form phagolysosome Microbe is then killed and digested by lysosomal enzymes leaving a residual body Residual material is removed from phagocyte by exocytosis Adherence is made possible by recognizing the pathogen Complementary proteins Vaccine Pathogen destruction Digestion by lysosomal enzymes Respiratory burst free radicals which kill cells K enters phagosome pH rises activates protein digesting enzymes that digest invader Budesa 3 Defensins are chemicals produced by neutrophils that pierce the pathogen membrane Objective 5 Describe the responses to injury reactive hyperemia and the mechanisms of occlusion training Upon injury o Release of chemical mediators such as cytokines promote inflammation and attract WBC histamine by mast cells kinins prostaglandins leukotrienes and complement will induce vasodilation of small blood vessels in injured aread Increased blood flow hyperemia account for redness heat o Chemicals also increase permeability of capillaries which exudates accumulate fluid with clotting factors and antibodies which cause swelling pressure on nerve causes pain Surge of fluids help to dilute harmful substance and delivers important proteins to site Fibrin mesh Reactive hyperemia mediated vasodilation Occlusion mechanisms o Fiber type recruitment o Accumulation of metabolites lactate GH o mTOR activation protein synthesis pathway Objective 6 Describe Antimicrobial Proteins Enhance the innate defenses by attacking microorganisms not allowing reproduction Interferons o Secreted by virus infected cells o Diffuse to nearby cells o Stimulate production of proteins that will interfere with viral replication in healthy cells o Gamma interferon Secreted by lymphocytes Enhances T cell activity Used to treat chronic granulomatous disease abnormal WBC that can ingest but not kill certain bacteria susceptible to infection o Alpha interferon Secreted by most leukocytes except lymphocytes Reduce inflammation Used to treat genital warts and some hepatitis C o Beta interferon Secreted by fibroblasts Reduce inflammation Used to treat MS Complement o Inactive proteins in blood Budesa 4 o Cascade of activation of proteins activated by injury o This activation releases chemicals which amplify inflammation through vasodilatory o At least 20 plasma proteins that normally circulate in blood in an inactive state o Groups C1 C9 factors B D and P regulatory proteins o Amplify the inflammatory process causes cell lysis of certain bacteria and other cell release type o Enhances the effectiveness of both innate and adaptive defense Objective 7 Describe two biochemical pathways activate the complement system o Involves binding of antibodies produced by adaptive immune system to the invading organisms and the subsequent binding of C1 to the antigen antibody complexes complement fixation o Factors B D and P interact with polysaccharide molecules on the surface of certain Classical pathway Alternative pathway microorganisms Converging o They converge on C3 cleaving into C3a and C3b o C3b will bind to target cell s surface and trigger the insertion of MAC which will form and stabilize a hole in the membrane causing lysis via influx of water o C3b will also coat microorganisms opsonization allowing neutrophils and macrophages to engulf and destroy more rapidly o C3a will amplify inflammatory response o C reactive protein is produced by the liver and is used as a clinical marker to assess acute infection of inflammation Binds to certain surface molecules of pathogens and damaged body cells Targets them for disposal by phagocytes and complement Also binds to C1 to activate complement
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