Power Point 1 The Immune System Objective 1 Define the immune system and its 3 lines of defense Immune system o Functional system made up of two intrinsic defense systems that act independently and cooperatively to provide resistance to disease Innate nonspecific defense system 1st and 2nd lines of defense respond within minutes 1st external membranes skin mucosa 2nd takes effect when 1st has been penetrated inflammation proteins phagocytes Adaptive specific defense system 3rd line of defense Attacks foreign substances This system takes longer than the innate to work Objective 2 Explain how the innate and adaptive systems are intertwined Innate and adaptive systems are intertwined Proteins released during an innate response alerts cells of the adaptive system about the presence of a foreign substance Essentially the innate system sets the adaptive system up to be effective Surface barriers skin mucous membranes Internal defenses phagocytes fever NK cells antimicrobial proteins inflammation Innate defenses Adaptive defenses Humoral immunity B cells Cellular immunity T cells Objective 3 What are surface barriers and how do they function as the first line of defense Skin mucous membranes and their secretions are the body s 1st line of defense Keratin keratinization hardening in the skin provides a tough barrier as the first line Mucous membranes provide the lining for all body cavities that open to the exterior Serve as physical barriers Also secrete protective chemicals Skin keratinized epithelial membrane Resistant to most weak acids and bases toxins Mucous membranes Protective chemicals secreted 1 Acidity of skin secretions pH 3 5 inhibits bacterial growth 2 Stomach mucosa secretes HCl and protein digesting enzymes to kill microorganisms 3 Saliva and lacrimal fluid contain lysozymes enzyme to destroy bacteria 4 Mucous to trap microorganisms trying to enter these openings Little cut can enable and elicit internal innate Objective 4 Explain Nonspecific Cellular Chemical Defense the second line of defense including phagocytes phagocytosis phagocyte mobilization and other factors in this line 2nd line of defense killing pathogens and repair tissue Phagocytes 2 types confront pathogens Macrophages leave the bloodstream in search of foreign substances Neutrophils type of white blood cell that becomes phagocytic upon an encounter Both derive from WBC Natural killer cells NK cells Inflammatory response Antimicrobial proteins o Fever Phagocytosis Complement proteins and interferons 1 Phagocyte adheres to pathogens or debris microbe 2 Phagocyte forms pseudopods that eventually engulf the particles forming a phagosome Plasmic extensions bind to the particle and pull it inside a membrane lined vacuole now a phagosome 3 Lysosome fuses with the phagocytic vesicle forming a phagolysosome 4 Lysosomal enzymes digest the particles leaving a residual body Microbe is killed and digested 5 Exocytosis of the vesicle removes indigestible and residual material Adherence is made possible by recognizing the pathogen Complementary proteins help with this vaccine o methods of pathogen destruction simple digestion by lysosomal enzymes o o o o o o o o o o o o o o o o o o 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 Natural Killer Cells Non phagocytic Located in blood and lymph Defensive cells that can kill infected cells before the adaptive immune system is activated Including cancer cells They eliminate cells through direct contact by 1 Determining the lack of cell surface receptors 2 Determining certain cell surface sugars Secrete chemicals that enhance the inflammatory response Stimulate apoptosis of target infected cell cell death Phagocyte Mobilization Phagocytes flooding injured area after inflammation by 4 steps 1 Leukocytosis damaged cells induce release of neutrophils from red bone marrow to increase WBCs in blood 2 Margination clinging of phagocytes to inner walls of capillaries Inflamed cells sprout cell adhesion molecules CAMs Neutrophils adhere to CAMs on inner walls of capillaries 3 Diapedesis chemical signaling allows neutrophils to squeeze through capillary walls 4 Chemotaxis inflammatory chemicals which act as magnets chemotactic agents to draw in phagocytes Neutrophils and monocytes thus macrophages monocyte follows neutrophil and they become macrophages at the site of injury Objective 5 Describe the responses to injury reactive hyperemia and the mechanisms of occlusion training Innate to internal defenses Inflammatory response is triggered when body tissues are injured 1 Prevents the spread of damaging agents to nearby tissues 2 Disposes of cell debris 3 Sets the stage for repair Four cardinal signs redness heat swelling and pain may hinder joint movement impairment of function Upon injury Release of chemical mediators such as cytokines promote inflammation and attract WBCs histamine by mast cells kinins prostaglandins leukotrienes and complements will induce vasodilation of small blood vessels in the injured area More blood flow hyperemia accounts for redness and heat Chemicals also increase the permeability of capillaries exudates accumulate fluid with clotting factors and antibodies which causes swelling pressure on nerves causes pain Surge of fluids helps to dilate harmful substances and delivers important proteins to the site Fibrin mesh Raynaud Phenomenon Occlusion An example of reactive hyperemia constriction of a small skin blood vessel Results in reactive hyperemia mediated vasodilation Mechanisms are 1 Fiber type recruitment 2 Accumulation of metabolites lactate GH 3 mTOR activation protein synthesis pathway Objective 6 Describe Antimicrobial Proteins Enhance the innate defenses by attacking microorganisms not allowing reproduction Interferons part of cytokine produced by lymphocyte Secreted by virus infected cells Stimulate production of proteins that will interfere with viral replication in healthy cells Interferons work on HEALTHY cells but are produced by infected cells Complement mainly produced in liver 20 25 complement proteins that MUST BE ACTIVATED Complement system inactive proteins in blood Cascade of activation of proteins activated by injury This activation releases chemicals which amplify inflammation through vasodilatory release 2 pathways of activation classical and alternative Viruses damage
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