A P Exam 3 Study Guide IMMUNE SYSTEM Immune system functional system made up of 2 intrinsic defense systems that act independently and cooperatively to provide resistance to disease Innate Defense System non specific respond within minutes 1st External membranes skin mucosa 2nd Inflammation proteins phagocytes takes effect when 1st has been penetrated Adaptive Defense System specific takes longer than innate to work 3rd attacks foreign substances Innate and Adaptive are intertwined innate response alerts adaptive defense system of a foreign substance INNATE DEFENSE SYSTEM Surface Barriers skin mucous membranes and their secretions 1st line of defense Skin keratinized epithelial membrane Keratinization hardening due to accumulation of keratin tough fibrous protein Resistant to most weak acids weak bases toxins Mucous Membranes lining for all body cavities open to the exterior Secrete protective chemicals o Skin secretions pH of 3 5 inhibits bacterial growth o Stomach secretions HCl and protein digesting enzymes kill microorganisms bacteria o Saliva and lacrimal secretions lysozymes enzyme to destroy o Mucus traps microorganisms trying to enter openings Non specific Cellular and Chemical Defense kill pathogens and repair tissue 2nd line of defense Phagocytes confront pathogens 2 types o Macrophages leave blood stream in search of a foreign substance o Neutrophils type of WBC that becomes phagocytic upon encounter o BOTH derived from WBC Phagocytosis phagocyte engulfs debris 1 Phagocyte adheres to microbe Made possible by recognizing the pathogen Help from complimentary proteins 2 Plasmic extensions bind to debris and pull it into a membrane lined vacuole Now called a phagosome 3 Phagosome fuses with lysosome phagolysosome Contains strong digestive enzymes 4 Pathogen Destruction by Simple digestion by lysosomal enzymes Respiratory Burst free radicals that kill cells K enters phagosome pH rises and activates digesting enzymes Defensins chemicals produced by neutrophils that pierce pathogen membrane 5 Residual indigestible material is removed from phagocyte by exocytosis cell membrane extracellular space Natural Killer cells NK cells defensive cells that can kill infected cells before adaptive immune system is activated nonphagocytic o Located in blood and lymph o Secrete chemicals that enhance an inflammatory response o Stimulate apoptosis of infected cell o Eliminate cells through direct contact by Determining lack of cell surface receptors Determining certain cell sugars Inflammatory Response triggered when body tissues are injured o 4 cardinal signs redness heat swelling pain o Prevents the spread of damaging agents to nearby tissue o Disposes of cell debris an pathogens o Sets stage for repair o Upon injury Chemical mediators released Cytokines promote inflammation and attract WBC Histamine by mast cells Kinins Prostaglandins Leukotrienes Induce vasodilation of small blood vessels in injured area increased blood flow hyperemia accounts for redness and heat Increases permeability of capillaries causes exudate to accumulate fluid with antibodies and clotting factors swelling Pressure on nerves pain Fibrin mesh Phagocyte Mobilization phagocytes flooding injured area after inflammation 1 Leukocytosis damaged cells induce release of neutrophils from red bone marrow to increase WBC count 2 Margination clinging of phagocytes to inner walls of capillaries Inflamed cells sprout CAMs cell adhesion molecules Neutrophils adhere to CAMs on inner walls 3 Diapedesis chemical signaling allows neutrophils to squeeze through capillary walls phagocytes 4 Chemotaxis inflammatory chemicals chemotactic agents draw in Antimicrobial Proteins enhance innate defenses by attacking microorganisms and not allowing reproduction Interferons small proteins that will interfere will viral replication in healthy cells by blocking protein synthesis and degrading viral RNA secreted by virus infected cells Gamma Interferon secreted by lymphocytes enhances T cell activity Used to treat chronic granulomatous abnormal WBCs that can ingest but not kill certain bacteria easily susceptible to infections Alpha Interferon secreted by leukocytes except lymphocytes Used to treat genital warts and some success with Hepatitis reduce inflammation C Beta Interferon secreted by fibroblasts reduce inflammation Used to treat MS demyelinating disease Complement group of at least 20 plasma proteins that normally circulate in the blood in an inactive state Proteins include C1 C9 factors B D P several regulatory proteins Activated by injury The activation causes the release of chemicals that amplify the inflammatory process through vasodilatory release Causes cell lysis of certain bacteria and other cell types Enhances effectiveness of both innate and adaptive defenses Classical and Alternative Pathways of Activation Classical involves the binding of antibodies produced by the adaptive immune system to the invading organisms AND the subsequent binding of C1 to the antigen antibody complexes complement fixation Alternative factors B D P interact with polysaccharide molecules on the surface of certain microorganisms The 2 pathways converge on C3 cleaving it into C3a and C3b C3b will bind to target cell s surface and trigger the insertion of MAC membrane attack complex hole is formed in the membrane causing lysis via influx of water C3b will cover the microorganism opsonization allowing neutrophils and macrophages to engulf destroy more rapidly C3a will amplify inflammatory response C reactive protein produced by liver is used as a clinical marker to assess acute infection of inflammation Binds to certain surface molecules of pathogens damaged body cells Targets them for disposal by phagocytes and complement Also binds to C1 to activate complement Fever systemic response to invading microorganisms elevated body temp o Body temp regulated by neurons in hypothalamus o Body temp changes in response to pyrogens fever inducing substances that secreted by leukocytes and macrophages o High fever is dangerous denatures enzymes and proteins o Mild Moderate fever is beneficial because Causes liver to retain Fe and Zn instead of releasing them would cause bacteria to multiply Increases metabolic rate of tissue cells speeds up repair Occlusion Training causing blockage of blood to muscle groups being exercised o Results in reactive hyperemia mediated vasodilation o Mechanisms Fiber Type recruitment Accumulation of metabolites lactate GH mTOR
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