1. Chapter 12 The Lymphatic System and Body Defenses
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 12 The Lymphatic System and Body Defenses
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2. Lymph Nodes Slide 12.6b Figure 12.3
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3. The Lymphatic System Two parts Lymphatic system functions
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
Slide 12.1
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4. Lymphatic Characteristics
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
Slide 12.2
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5. Lymphatic Vessels Slide 12.3b Figure 12.1
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6. Lymphatic Vessels Lymphatic collecting vessels
Collects lymph from lymph capillaries
Carries lymph to and away from lymph nodes
Figure 12.2
Slide 12.4a
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7. Lymphatic Vessels Lymphatic collecting vessels (continued)
Returns fluid to circulatory veins near the heart
Right lymphatic duct
Thoracic duct
Figure 12.2
Slide 12.4b
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8. Lymph Materials returned to the blood Water Blood cells Proteins
Slide 12.5a
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9. Lymph Harmful materials that enter lymph vessels Bacteria Viruses
Cancer cells
Cell debris
Slide 12.5b
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10. Lymph Nodes 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
Slide 12.6a
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11. Lymph Nodes Slide 12.6b Figure 12.3
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12. Lymph Node Structure Slide 12.7b Figure 12.4
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13. Other Lymphoid Organs
Several other organs contribute to lymphatic function
Spleen
Thymus
Tonsils
Peyer’s patches
Figure 12.5
Slide 12.9
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14. The Spleen 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
Slide 12.10
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15. The Thymus Located low in the throat, overlying the heart
Functions at peak levels only during childhood
Produces hormones (like thymosin) to program lymphocytes
Slide 12.11
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16. Tonsils Small masses of lymphoid tissue around the pharynx
Trap and remove bacteria and other foreign materials
Tonsillitis is caused by congestion with bacteria
Slide 12.12
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18. Peyer’s Patches Found in the wall of the small intestine
Resemble tonsils in structure
Capture and destroy bacteria in the intestine
Slide 12.13
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19. Mucosa-Associated Lymphatic Tissue (MALT)
Includes:
Peyer’s patches
Tonsils
Other small accumulations of lymphoid tissue
Acts as a guard to protect respiratory and digestive tracts
Slide 12.14
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20. Body Defenses
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
Slide 12.15a
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21. Body Defenses Specific defense system
Specific defense is required for each type of invader
Also known as the immune system
Slide 12.15b
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22. Nonspecific Body Defenses
Body surface coverings
Intact skin
Mucous membranes
Specialized human cells
Chemicals produced by the body
Slide 12.16
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23. Surface Membrane Barriers – First Line of Defense
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
Slide 12.17a
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24. Surface Membrane Barriers – First Line of Defense
Stomach mucosa
Secretes hydrochloric acid
Has protein-digesting enzymes
Saliva and lacrimal fluid contain lysozyme
Mucus traps microogranisms in digestive and respiratory pathways
Slide 12.17b
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25. Defensive Cells Phagocytes (neutrophils and macrophages)
Engulfs foreign material into a vacuole
Enzymes from lysosomes digest the material
Slide 12.18a
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Figure 12.6b

26. Macrophage attacking e-coli. Macrophage attacking e-coli.
                                        
                                        

27. Defensive Cells Natural killer cells Can lyse and kill cancer cells
Can destroy virus- infected cells
Slide 12.18b
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Figure 12.6b

29. Inflammatory Response - Second Line of Defense
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
Slide 12.19
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30. Functions of the Inflammatory Response
Prevents spread of damaging agents
Disposes of cell debris and pathogens
Sets the stage for repair
Slide 12.20
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31. Steps in the Inflammatory Response
Figure 12.7
Slide 12.21
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32. Antimicrobial Chemicals
Complement
A group of at least 20 plasma proteins
Activated when they encounter and attach to cells (complement fixation)
Figure 12.8
Slide 12.22a
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33. Antimicrobial Chemicals
Complement (continued)
Damage foreign cell surfaces
Will rupture or lyse the foreign cell membrane
Figure 12.8
Slide 12.22b
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35. Antimicrobial Chemicals
Interferon
Secreted proteins of virus-infected cells
Bind to healthy cell surfaces to inhibit viruses binding
Slide 12.22c
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36. Interferons are a family species-specific proteins synthesized by eukaryotic cells in response to viruses and a variety of natural and synthetic stimuli. There are several different interferons commonly used as therapeutics, termed alpha, beta, and gamma. These peptides are used to treat hairy cell leukemia, AIDS-related Kaposi's sarcoma, laryngeal papillomatosis, genital warts, and chronic granulomatous disease. Side effects include black tarry stools, blood in the urine, confusion, and loss of balance.

37. Fever 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
Slide 12.23
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38. Specific Defense: The Immune System – Third Line of Defense
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
Slide 12.24
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39. Types of Immunity Humoral immunity Cellular immunity
Antibody-mediated immunity
Cells produce chemicals for defense
Cellular immunity
Cell-mediated immunity
Cells target virus infected cells
Slide 12.25
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40. Antigens (Nonself)
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
Slide 12.26
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41. Self-Antigens 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
Slide 12.27
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42. Allergies
Many small molecules (called haptens or incomplete antigens) are not antigenic, but link up with our own proteins
The immune system may recognize and respond to a protein-hapten combination
The immune response is harmful rather than protective because it attacks our own cells
Slide 12.28
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45. Cells of the Immune System
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
Slide 12.29
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46. Activation of Lymphocytes
Figure 12.9
Slide 12.30
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47. Humoral (Antibody-Mediated) Immune Response
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)
Slide 12.31a
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48. Humoral (Antibody Mediated) Immune Response
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)
Slide 12.31b
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49. Humoral Immune Response
Figure 12.10
Slide 12.32
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50. Active Immunity Your B cells encounter antigens and produce antibodies
Active immunity can be naturally or artificially acquired
Figure 12.12
Slide 12.34
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51. Passive Immunity 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”
Slide 12.35
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52. Antibodies (Immunoglobulins) (Igs)
Soluble proteins secreted by B cells (plasma cells)
Carried in blood plasma
Capable of binding specifically to an antigen
Slide 12.37
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53. Antibody Classes
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
Slide 12.39
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54. Cellular (Cell-Mediated) Immune Response
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
Slide 12.42
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55. Cellular (Cell-Mediated) Immune Response
Figure 12.15
Slide 12.43
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56. T Cell Clones Cytotoxic T cells Helper 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
Slide 12.44a
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58. T Cell Clones Suppressor T cells
Release chemicals to suppress the activity of T and B cells
Stop the immune response to prevent uncontrolled activity
A few members of each clone are memory cells
Slide 12.44b
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59. Summary of the Immune Response
Figure 12.16
Slide 12.45
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60. Organ Transplants and Rejection
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
Slide 12.46a
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61. Organ Transplants and Rejection
Autografts and isografts are ideal donors
Xenografts are never successful
Allografts are more successful with a closer tissue match
Slide 12.46b
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62. Disorders of Immunity: Immunodeficiencies
Production or function of immune cells or complement is abnormal
May be congenital or acquired
Includes AIDS – Acquired Immune Deficiency Syndrome
Slide 12.49
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63. Disorders of Immunity: Autoimmune Diseases
The immune system does not distinguish between self and nonself
The body produces antibodies and sensitized T lymphocytes that attack its own tissues
Slide 12.50a
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64. Disorders of Immunity: Autoimmune Diseases
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
Slide 12.50b
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65. Disorders of Immunity: Autoimmune Diseases
Examples of autoimmune diseases (continued)
Systemic lupus erythematosus (SLE) – affects kidney, heart, lung and skin
Glomerulonephritis – impairment of renal function
Slide 12.50c
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66. Immune Deficiency: AIDS
HIV targets cells
Retrovirus attaches to CD4 receptors of T helper cells
Transmission: Body fluids, i.e., blood, semen, breast milk, vaginal secretions

67. The Structure of HIV
Figure 9.19

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

69. 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….

70. AIDS Pandemic 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.
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