1. Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Elaine N. Marieb Chapter 12 The Lymphatic System and Body Defenses

2. Lymph Nodes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.3

3. The Lymphatic System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Two parts  Lymphatic vessels  Lymphoid tissues and organs  Lymphatic system functions  Transport fluids back to the blood  Play essential roles in body defense and resistance to disease  Absorb digested fat at the intestinal villi

4. Lymphatic Characteristics Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymph – excess tissue fluid carried by lymphatic vessels  Properties of lymphatic vessels  One way system toward the heart  No pump  Lymph moves toward the heart  Milking action of skeletal muscle  Rhythmic contraction of smooth muscle in vessel walls

5. Lymphatic Vessels Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.1

6. Lymphatic Vessels Slide 12.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphatic collecting vessels  Collects lymph from lymph capillaries  Carries lymph to and away from lymph nodes Figure 12.2

7. Lymphatic Vessels Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphatic collecting vessels (continued)  Returns fluid to circulatory veins near the heart  Right lymphatic duct  Thoracic duct Figure 12.2

8. Lymph Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Materials returned to the blood  Water  Blood cells  Proteins

9. Lymph Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Harmful materials that enter lymph vessels  Bacteria  Viruses  Cancer cells  Cell debris

10. Lymph Nodes Slide 12.6a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Filter lymph before it is returned to the blood  Defense cells within lymph nodes  Macrophages – engulf and destroy foreign substances  Lymphocytes – provide immune response to antigens

11. Lymph Nodes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.3

12. Lymph Node Structure Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.4

13. Other Lymphoid Organs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Several other organs contribute to lymphatic function  Spleen  Thymus  Tonsils  Peyer’s patches Figure 12.5

14. The Spleen Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located on the left side of the abdomen  Filters blood  Destroys worn out blood cells  Forms blood cells in the fetus  Acts as a blood reservoir

15. The Thymus Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located low in the throat, overlying the heart  Functions at peak levels only during childhood  Produces hormones (like thymosin) to program lymphocytes

17. Tonsils Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Small masses of lymphoid tissue around the pharynx  Trap and remove bacteria and other foreign materials  Tonsillitis is caused by congestion with bacteria

19. Peyer’s Patches Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found in the wall of the small intestine  Resemble tonsils in structure  Capture and destroy bacteria in the intestine

20. Body Defenses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The body is constantly in contact with bacteria, fungi, and viruses (pathogens)  The body has two defense systems for foreign materials  Nonspecific defense system  Mechanisms protect against a variety of invaders  Responds immediately to protect body from foreign materials

21. Body Defenses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Specific defense system  Specific defense is required for each type of invader  Also known as the immune system

22. Nonspecific Body Defenses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Body surface coverings  Intact skin  Mucous membranes  Specialized human cells  Chemicals produced by the body

23. Surface Membrane Barriers – First Line of Defense Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The skin  Physical barrier to foreign materials  pH of the skin is acidic to inhibit bacterial growth  Sebum is toxic to bacteria  Vaginal secretions are very acidic

24. Surface Membrane Barriers – First Line of Defense Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Stomach mucosa  Secretes hydrochloric acid  Has protein-digesting enzymes  Saliva and lacrimal fluid contain lysozyme  Mucus traps microogranisms in digestive and respiratory pathways

25. Defensive Cells  Phagocytes= white cells (neutrophils and macrophages)  Engulfs foreign material into a vacuole  Enzymes digest the material

26. Defensive Cells – Second Line of Defense  Phagocytes= white cells (neutrophils and macrophages)  Engulfs foreign material into a vacuole  Enzymes digest the material

27. Defensive Cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Phagocytes: white blood cells that engulf a foreign particle  Natural killer cells: “police” the body in blood and lymph  A kind of white blood cell that  Can lyse and kill cancer cells  Can destroy virus- infected cells Figure 12.6b

28. Inflammatory Response - Second Line of Defense Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Triggered when body tissues are injured  Produces four cardinal signs  Redness  Heat  Swelling  Pain  Results in a chain of events leading to protection and healing

29. Functions of the Inflammatory Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Prevents spread of damaging agents  Disposes of cell debris and pathogens  Sets the stage for repair

30. Steps in the Inflammatory Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.7

31. Antimicrobial Chemicals Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Complement  A group of at least 20 plasma proteins  Activated when they encounter and attach to cells Figure 12.8

32. Antimicrobial Chemicals Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Complement (continued)  Damage foreign cell surfaces  Will rupture or lyse the foreign cell membrane Figure 12.8

33. Antimicrobial Chemicals Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Interferon  Secreted proteins of virus-infected cells  Bind to healthy cell surfaces to inhibit viruses binding

34. Fever Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Abnormally high body temperature  Hypothalmus heat regulation can be reset by pyrogens (secreted by white blood cells)  High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria  Fever also increases the speed of tissue repair

35. Specific Defense: The Immune System – Third Line of Defense Slide 12.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antigen specific – recognizes and acts against particular foreign substances  Systemic – not restricted to the initial infection site  Has memory – recognizes and mounts a stronger attack on previously encountered pathogens

36. Types of Immunity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Humoral immunity  Antibody-mediated immunity  Cells produce chemicals for defense  Cellular immunity  Cell-mediated immunity  Cells target virus infected cells

37. Antigens (Nonself) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Any substance capable of exciting the immune system and provoking an immune response  Examples of common antigens  Foreign proteins  Nucleic acids  Large carbohydrates  Some lipids  Pollen grains  Microorganisms

38. Self-Antigens Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Human cells have many surface proteins  Our immune cells do not attack our own proteins  Our cells in another person’s body can trigger an immune response because they are foreign  Restricts donors for transplants

39. Cells of the Immune System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphocytes  Originate from hemocytoblasts in the red bone marrow  B lymphocytes become immunocompetent in the bone marrow  T lymphocytes become immunocompetent in the thymus  Macrophages  Arise from monocytes  Become widely distributed in lymphoid organs

40. Activation of Lymphocytes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.9

41. Humoral (Antibody-Mediated) Immune Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  B lymphocytes with specific receptors bind to a specific antigen  The binding event activates the lymphocyte to undergo clonal selection  A large number of clones are produced (primary humoral response)

42. Humoral (Antibody Mediated) Immune Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most B cells become plasma cells  Produce antibodies to destroy antigens  Activity lasts for four or five days  Some B cells become long-lived memory cells (secondary humoral response)

43. Humoral Immune Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.10

44. Active Immunity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Your B cells encounter antigens and produce antibodies  Active immunity can be naturally or artificially acquired Figure 12.12

45. Passive Immunity Slide 12.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antibodies are obtained from someone else  Conferred naturally from a mother to her fetus  Conferred artificially from immune serum or gamma globulin  Immunological memory does not occur  Protection provided by “borrowed antibodies”

46. Antibodies (Immunoglobulins) (Igs) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Soluble proteins secreted by B cells (plasma cells)  Carried in blood plasma  Capable of binding specifically to an antigen

47. Antibody Classes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antibodies of each class have slightly different roles  Five major immunoglobulin classes – (Do Not Need to know!)  IgM – can fix complement  IgA – found mainly in mucus  IgD – important in activation of B cell  IgG – can cross the placental barrier  IgE – involved in allergies

48. Cellular (Cell-Mediated) Immune Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antigens must be presented by macrophages to an immunocompetent T cell (antigen presentation)  T cells must recognize nonself and self (double recognition)  After antigen binding, clones form as with B cells, but different classes of cells are produced

49. Cellular (Cell-Mediated) Immune Response Slide 12.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.15

50. T Cell Clones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cytotoxic T cells  Specialize in killing infected cells  Insert a toxic chemical (perforin)  Helper T cells  Recruit other cells to fight the invaders  Interact directly with B cells

51. Summary of the Immune Response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.16

52. Organ Transplants and Rejection Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Major types of grafts  Autografts – tissue transplanted from one site to another on the same person  Isografts – tissue grafts from an identical person (identical twin)  Allografts – tissue taken from an unrelated person  Xenografts – tissue taken from a different animal species

53. Disorders of Immunity: Immunodeficiencies Slide 12.49 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Production or function of immune cells or complement is abnormal  May be congenital or acquired  Includes AIDS – Acquired Immune Deficiency Syndrome

54. Disorders of Immunity: Autoimmune Diseases Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The immune system does not distinguish between self and nonself  The body produces antibodies and sensitized T lymphocytes that attack its own tissues

55. Disorders of Immunity: Autoimmune Diseases Slide 12.50b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Examples of autoimmune diseases  Multiple sclerosis – white matter of brain and spinal cord are destroyed  Myasthenia gravis – impairs communication between nerves and skeletal muscles  Juvenile diabetes – destroys pancreatic beta cells that produce insulin  Rheumatoid arthritis – destroys joints

56. Disorders of Immunity: Autoimmune Diseases Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Examples of autoimmune diseases (continued)  Systemic lupus erythematosus (SLE) – affects kidney, heart, lung and skin  Glomerulonephritis – impairment of renal function

57. HIV targets cells Retrovirus attaches to CD4 receptors of T helper cells –Transmission: Body fluids, i.e., blood, semen, breast milk, vaginal secretions Immune Deficiency: AIDS

58. The Structure of HIV Figure 9.19

59. Time Course of the Progression of AIDS after HIV Infection Figure 9.21

60. AIDS progression: –Phase I: few weeks to a few years; flu like symptoms, swollen lymph nodes, chills, fever, fatigue, body aches. Virus is multiplying, antibodies are made but ineffective for complete virus removal –Phase II: within six months to 10 years; opportunistic infections present, Helper T cells affected, 5% may not progress to next phase –Phase III: Helper T cells fall below 200 per cubic millimeter of blood AND the person has an opportunistic infection or type of cancer. Person is now termed as having “AIDS” May include pneumonia, meningitis, tuberculosis, encephalitis, Kaposi’s sarcoma, and non-Hodgkin’s lumphoma….

61. More than 36 million infected with HIV worldwide Most infections in sub-Sahara of Africa Increasing spread in Asia and India Most often spread by heterosexual contact outside U.S. AIDS Pandemic

62. See Table 12.1 First and Second Line of Defense See Table 12.4 Function of Cells and Molecules Involved in Immunity See Figure 12.19 Summary of Immune Responses Summary of Body Defenses