The Lymphatic and Immune Systems 2009 The Mc

The Lymphatic and Immune Systems © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -2 Learning Outcomes 32. 1 List the pathways and organs of the lymphatic system and give their locations. 31. 2 Define lymph and tell how it is circulated in the body. 31. 3 Define the terms infection, pathogen, and antigen. 31. 4 List and describe the nonspecific body defense mechanisms. 31. 5 Explain the signs and causes of inflammation. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -3 Learning Outcomes (cont. ) 32. 6 Explain what is meant by body defenses. 32. 7 Define B cells and T cells and describe their locations and functions. 32. 8 Explain the importance of MHC proteins. 32. 9 List the different types of T cells and describe their functions. 32. 10 Explain how antibodies fight infection. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -4 Learning Outcomes (cont. ) 32. 11 List the different types of antibodies and tell how they differ. 32. 12 Define complement proteins and give their function. 32. 13 Explain the difference between the primary immune response and secondary immune response. 32. 14 Explain the four different types of acquired immunities. 32. 15 Describe the function of a vaccine. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -5 Learning Outcomes (cont. ) 32. 16 Define the terms cancer and carcinogen. 32. 17 Describe how cancers are diagnosed and treated. 32. 18 Explain how cancers are classified. 32. 19 Describe how allergies develop. 32. 20 Describe the causes, signs and symptoms, and treatments of other common immune disorders. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -6 Introduction n Immune system n Protects the body against n n n Bacteria Viruses Fungi Toxins Parasites Cancer n Lymphatic system n n Works with immune system to remove disease-causing agents Organs n n n Thymus Spleen Lymph nodes © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -7 The Lymphatic System n Network of connecting vessels n n n Collects fluid (lymph) between cells and returns it to bloodstream Picks up lipids from digestive organs and transports them to blood stream Functions to defend the body against pathogens © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -8 Lymphatic System: Pathways n Lymphatic capillaries n n Extend into interstitial spaces Permeable, thin walls pick up fluid, now lymph Delivers lymph to lymphatic vessels Lymphatic vessels n Deliver lymph to lymph nodes n n Cells in nodes can remove pathogens from lymph and start an immune response Leaves nodes through efferent lymphatic vessels Lymph System © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -9 Lymphatic System: Pathways (cont. ) n Lymphatic trunks n n n Receive lymph from efferent lymphatic vessels Deliver it to Lymphatic collecting ducts n Thoracic duct n n Lymph System Left side of head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs Right lymphatic duct n Right side of head and neck, right arm, and right side of chest © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -10 Lymphatic System: Tissue Fluid and Lymph n Interstitial fluid n n n Fluid in spaces between cells that has leaked from blood capillaries and has not been picked up by body cells High in nutrients, oxygen, and small proteins Becomes lymph n Pushed through lymphatic vessels by squeezing action of neighboring skeletal muscles and breathing movement © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -11 Back © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -12 Lymphatic System: Nodes n n Small, glandular structures Located along paths of larger lymphatic vessels n n Afferent lymphatic vessels – Lymph to node Efferent lymphatic vessels – Lymph from node © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -13 Lymphatic System: Nodes (cont. ) n n More lymph enters than can leave at one time Cells in nodes n n n Macrophages – digest unwanted pathogens Lymphocytes – start an immune response against pathogen Nodes can generate some lymphocytes © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -14 Lymphatic System: The Thymus and Spleen n Thymus n Soft, bi-lobed organ n Located just above the heart in the mediastinum n Large in children, shrinks as we age n Functions n Same as lymph nodes n Also produces lymphocytes n Produces thymosin – stimulates production of lymphocytes © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -15 Lymphatic System: The Thymus and Spleen (cont. ) n Spleen n Largest lymphatic organ n Located in the upper left quadrant of abdominal cavity n Functions n n Filters blood similarly to lymph nodes n Removes worn-out red cells If removed (splenectomy), liver takes over most of its function © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -16 Apply Your Knowledge What are the lymphatic collecting ducts and what area do they drain? ANSWER: The collecting ducts are: Thoracic duct, which drains the left side of the head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs; and the right lymphatic duct, which drains the right side of the head and neck, right arm, and right side of the chest. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -17 Defenses Against Disease n Infection n n Pathogen n n The presence of a pathogen in or on the body A disease-causing agent Innate immunity n Nonspecific defenses to protect against pathogens n Nonspecific defenses n Species resistance n Mechanical barriers n Chemical barriers n Phagocytosis n Fever n Inflammation © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -18 Defenses Against Disease: Specific Defenses n Immunities n n Protect against very specific pathogens Antigens n n Foreign substances in the body Haptens n Foreign substances too small to start an immune response by themselves n Other substances n n n Proteins – antibodies and complements WBCs – lymphocytes and macrophages Lymph system n n Cytokines – assist in immune response regulation Monokines – increase B cell production and stimulate WBC production © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -19 Defenses Against Disease (cont. ) Two major types of lymphocytes B Cells and T Cells Response Recognize antigens in the body B cells Respond to antigens by becoming plasma cells v Plasma cells make antibodies v Memory B cells produce stronger response with next exposure to antigen v T Cells Cell-mediated response v Bind to antigens on cells and attack them directly v Secrete lymphokines that increase T cell production and directly kill cells with antigens v © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -21 Defenses Against Disease (cont. ) n T cell activation n n Begins when macrophage ingests and digests pathogen with antigen on it Antigens are placed on cell membrane of macrophage T cell recognizes and binds to antigen and the major histocompatibility complex (MHC) on the surface of the macrophage Now can divide to form other types of T cells © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -22 Defenses Against Disease (cont. ) n Types n Cytotoxic T cells n n Helper T cells n n Protect body against viruses and cancer cells Increase antibody formation, memory cell formation, B cell formation, and phagocytosis Memory T cells n n Remember the pathogen that activated original T cell Later exposures trigger an immune response more effective than initial response © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -23 Defenses Against Disease (cont. ) n Natural killer (NK) cells n Type of lymphocyte n Primarily target cancer cells n Kill on contact n Do not recognize a specific antigen © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -24 Apply Your Knowledge ANSWER: Identify whether each item refers to T cells, B cells, or NK cells: ___ NK Primarily target cancer cells Right on ___ B Respond to antigens by becoming plasma cells Target! T Must be activated to respond to an antigen ___ T Bind to antigens on cells and attack them directly ___ NK Kill on contact T Need macrophages and MHC for activation ___ B Make antibodies against specific antigen ___ © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -25 Antibodies n Also called immunoglobulins n Ig. A n n Ig. D n n n Prevents pathogens from entering body Found on B cell membranes Thought to control B cell activity Ig. E n n Found with Ig. A Involved in triggering allergic reactions © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -26 Antibodies (cont. ) n Ig. G n n n Recognizes bacteria, viruses, and toxins Activates complements Ig. M n n Large and binds to antigens on food, bacteria, or incompatible blood cells Activates compliments © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -27 Antibodies (cont. ) n Actions that occur when antibodies bind to antigens n n Allow phagocytes to recognize and destroy antigens Cause antigens to clump together, causing them to be destroyed by macrophages n Cover the toxic portions of antigens, making them harmless n Activate complement n n Group of proteins in serum that attack pathogens by forming holes in them Attract macrophages to pathogens and can stimulate inflammation © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -28 Apply Your Knowledge What are the possible actions that occur when antibodies bind to antigens? ANSWER: Possible actions include: v They allow phagocytes to recognize and destroy antigens. v They make antigens clump together, causing them to be destroyed by macrophages. v They cover the toxic portions of antigens to make them harmless. v They activate complements. Very Good! © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -29 Immune Responses and Acquired Immunity n Primary immune response occurs with first exposure to antigen n Slow process Memory cells are formed Secondary immune response with next exposure to same antigen n n Quick and carried out by memory cells Usually prevents person from developing disease from the antigen © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -30 Immune Responses and Acquired Immunity (cont. ) n Naturally acquired active immunity n n Natural exposure to antigen – having an illness Makes antibodies and memory cells Long-lasting Artificially acquired active immunity n n n Injected with pathogen – immunizations Makes antibodies and memory cells Long-lasting © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -31 Immune Responses and Acquired Immunity (cont. ) n Naturally acquired passive immunity n Acquired from mother n n Breast milk Placenta Short-lived Artificially acquired passive immunity n n Injected with antibodies (such as antivenom) Short-lived © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -32 Apply Your Knowledge After you give an immunization to a 2 -year-old, her mother asks you why this will work to prevent her from getting a disease. ANSWER: Immunization is an artificially acquired immunity because a person develops this immunity by being injected with a pathogen and then making antibodies and memory cells against the pathogen. © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -33 Major Immune System Disorders n Cancer n n n Uncontrolled growth of abnormal cells form malignant tumors 200 known types Treatment based on stage 0 – very early; cancer cells localized I – spread to deeper layers or some in surrounding tissues II – spread to surrounding tissues but contained in primary site III – spread beyond primary site into nearby areas IV – spread to other organs Recurrent – reappeared after treatment © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -34 Major Immune System Disorders (cont. ) n Allergies n Immune response to an allergen n n Ig. E antibodies bind to allergens and stimulate mast cells to release histamine and heparin n n Can be excessive Triggers allergic response Allergy shots n n Small amounts of allergen stimulates production of Ig. G to prevent Ig. E from binding to antigen Ig. G antibodies do not stimulate mast cells, so immune response is not generated © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -35 Major Immune System Disorders (cont. ) n Signs/symptoms n Inhaled allergens – runny nose, sneezing, coughing, wheezing n Ingested allergens – nausea, vomiting, diarrhea n Skin allergens – rashes n n n Allergens in blood – most life-threatening; can affect many organs Treatment n Antihistamines, decongestants – OTC or prescription n Epinephrine for anaphylaxis – vasoconstriction, increasing BP Anaphylaxis – life-threatening response © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -36 Common Immune System Disorders n Autoimmune disease n n Body attacks its own antigens Examples n n n Scleroderma Rheumatoid arthritis Multiple sclerosis Glomerulonephritis Chron’s disease Diabetes mellitus, type I © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -37 Common Immune System Disorders (cont. ) Disorder Description AIDS Development of severe signs and symptoms caused by HIV as it destroys lymphocytes; leaves immune system weakened and susceptible to other diseases Chronic fatigue syndrome (CFS) Condition of severe tiredness not relieved by rest and not related to other illnesses Lymphedema Blockage of lymphatic vessels results in tissue swelling that increases over time © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -38 Common IS Disorders (cont. ) Disorder Description Mononucleosis “Mono”; highly contagious viral infection spread through saliva of infected person Systemic lupus erythematous (SLE) Autoimmune disorder; antibodies produces that target own cells and tissues; affects women more often than men © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -39 Apply Your Knowledge Matching: ANSWER: G Immune response to a substance ___ A. CFS E Blockage of lymphatic vessels ___ B. SLE F “Kissing disease” ___ C. Cancer B “Butterfly” rash on face ___ D. Autoimmune disease A Severe tiredness ___ E. Lymphedema C Uncontrolled growth of abnormal cells ___ F. Mononucleosis D Body attack its own antigens ___ G. Allergy © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -40 In Summary n Immune system is the body’s major line of defense n n Primary function – protect against infection, toxins, and cancer Specific or nonspecific defenses n n n Lymphocytes are major cells of immune system Immune response may be primary or secondary Medical assistant must understand immune system n n n Aseptic technique Infection control Educate patients © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved

32 -41 End of Chapter Thought is an infection. In the case of certain thoughts, it becomes an epidemic. ~Wallace Stevens © 2009 The Mc. Graw-Hill Companies, Inc. All rights reserved