BSC2086 A P II Exam 3 Study Guide Lesson 12 The Lymphatic System Part II Lymphatic System and Body Defenses Body defenses provide resistance to fight infection illness and disease Two 2 Categories of Defenses Innate Nonspecific Defenses o o Adaptive Specific Defenses Innate Nonspecific Defenses Nonspecific resistance o Always work the same way against any type of invading agent Seven 7 Major Categories of Innate Nonspecific Defenses o Physical barriers keep hazardous materials outside the body o Phagocytes attack remove dangerous microorganisms o o Immunological surveillance NK cells constantly monitor normal tissues Interferons chemical messengers that trigger production of antiviral proteins in normal cells Antiviral Proteins do not kill viruses block replication in cell o Complement system of circulating proteins found in blood Assist antibodies in destruction of pathogens o Inflammatory response localized tissue level response that tends to limit spread of injury or infection o Fever a high body temperature Increases body metabolism Accelerates defenses Inhibits some viruses bacteria 1 BSC2086 A P II Exam 3 Study Guide Physical Barriers o Outer layer of skin o Hair o Epithelial layers of internal passageways o Secretions that flush away materials Sweat glands mucus urine Unless you have a UTI urine is fairly sterile Secretions that kill or inhibit microorganisms Enzymes lysozymes antibodies stomach acid Phagocytes o Two 2 Classes of Phagocytes Microphages neutrophils eosinophils Leave the bloodstream Enter peripheral tissues to fight infections Macrophages large phagocytic cells derived from monocytes Distributed throughout body Make up monocyte macrophage system o Activated macrophages respond to pathogens in several ways Engulf pathogen destroy it with lysosomal enzymes Bind to pathogen so other cells can destroy it Release toxic chemicals into interstitial fluid to destroy pathogen o All macrophages Move through capillary walls emigration Are attracted or repelled by chemicals in surrounding fluids chemotaxis Positive chemotaxis attract Negative chemotaxis repel Begin phagocytosis by attaching to a target adhesion surrounding it with a vesicle Immunological Surveillance o Carried out by natural killer NK cells 2 BSC2086 A P II Exam 3 Study Guide Detect foreign abnormal proteins on cells o Activated NK cells Identify attach to abnormal cell nonselective Golgi apparatus in NK cell forms perforin vesicles Vesicles release by exocytosis proteins called perforins Perforins lyse perforate abnormal plasma membrane Also attack cancer cells cells infected with viruses o Cancer cells with tumor specific antigens are identified as abnormal by Immunological Escape When cancer cells avoid NK cells Either avoid detection or destroy the NK cells that detect o Cells infected with viruses present abnormal proteins on plasma NK cells them membranes Allow NK cells to identify destroy them Interferons Proteins cytokines released by activated lymphocytes and macrophages o Cytokines Chemical messengers released by tissue cells Coordinate local activities or act as hormones to affect whole body o Stimulate macrophage activity NK cells o Slow inflammation 3 BSC2086 A P II Exam 3 Study Guide o Reduce rate of viral replication within a cell Complement System o Plasma contains 11 special complement C proteins Form complement system and complement antibody action o Complement Activation Complements work together in cascades Two 2 pathways activate the complement system o Classical Pathway Complement proteins become activated by binding to the antibody o Alternative Pathway Doesn t involve the antibody Classical Pathway fast method Complement protein binds to antibody molecule attached to antigen bacterium Bound protein acts as enzyme and catalyzes chain reaction Alternative Pathway slower less effective method Complement proteins interact within plasma resulting in the attachment of activated complement protein onto bacterial cell wall Reaction triggered by presence of foreign material 4 BSC2086 A P II Exam 3 Study Guide Both pathways end with form C3b Conversion of inactive complement protein C3 active Active form of C3b recruits other complement proteins to form a membrane attack complex MAC that creates a pore in the membrane o Allows water to start flowing in Multiple MACs cause cell lysis o Effects of Complement Activation Pore formation Destruction of target plasma membranes Five 5 complement proteins join to form membrane attack complex MAC causes cell to lyse Enhancement of phagocytosis Opsonization complement coated items attract phagocytes Histamine release from mast cells basophils Increases the degree of local inflammation and blood flow Inflammation Inflammatory Response o A localized response triggered by any stimulus that kills cells or injures tissues o Cardinal Signs and Symptoms Swelling tumor Redness tubor Heat calor Pain dolor symptom o Three 3 Effects of Inflammation Temporary repair barrier against pathogens Slows spread of pathogens into surrounding areas Mobilization of local and systemic defenses Facilitation of repairs regeneration o Products of Inflammation Necrosis Local tissue destruction in an area of injury Pus Mixture of debris and necrotic tissue Abscess Pus accumulated in an enclosed space 5 BSC2086 A P II Exam 3 Study Guide Fever A maintained body temperature above 37 C 99 F o Pyrogens Any material that causes the hypothalamus to raise body temperature Circulating pathogens toxins or antibody complexes o Endogenous Pyrogens or Interleukin 1 IL 1 A cytokine released by active macrophages Higher temperature may inhibit some viruses bacteria and increase body metabolism Specific Defenses Specific resistance immunity o Responds to specific antigens with coordinated action of T cells and B cells T Cells provide cell mediated immunity Defend against abnormal cells pathogens inside cells B Cells provide antibody mediated immunity Defend against antigens pathogens in body fluids Forms of Immunity Innate Present at birth o o Adaptive Develop after birth Active Antibodies develop after exposure to antigen Passive Antibodies are transferred from another source Active Immunity o Naturally acquired through environmental exposure to pathogens o Artificially induced through vaccine containing pathogens Stimulates immune system to produce antibodies 6 BSC2086 A P II Exam 3 Study Guide Passive Immunity o Naturally acquired antibodies acquired from the mother o Artificially induced
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