Ch11 or 13 body defenses & lymphatic system


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  • Figure 9.2: Animated! The lymphatic system collects fluid and functions in defense. The small green ovals show where some of the major lymph nodes are located. The system also includes patches of lymphoid tissue in the small intestine and in the appendix.
  • Figure 9.12: Animated! Antibodies can bind to antigens. ( a ) The Y-shaped structure of many antibodies. ( b ) How an antibody binds to an antigen. Each kind of antibody can bind only one kind of antigen. The antigen fits into grooves and bumps on the antibody molecules.
  • Figure 9.25: It is helpful to know how pathogens spread and what their reservoirs are. ( a ) Some recommended strategies for preventing the spread of infectious disease.
  • Ch11 or 13 body defenses & lymphatic system

    1. 1. Immunity and DiseaseThe Lymphatic System
    2. 2. Body Defense Mechanisms The body’s defense system Three lines of defense Distinguishing self from nonself Antibody-mediated responses and cell-mediated responses Steps of the adaptive immune response Active and passive immunity Monoclonal antibodies Problems of the immune system
    3. 3. The Body’s Defense System  Targets of the body’s defense mechanisms • Pathogens • Disease-causing bacteria, viruses, protozoans, fungi, parasitic worms, prions • Cancer cells • Once normal body cells whose genetic changes cause unregulated cell division
    4. 4. Overview of Body Defenses Every day we encounter a vast number of health threats Body defenses include physical barriers and two interacting sets of cells and proteins
    5. 5. Three Lines of Defense Protect the Body Physical barrier to invasion • Intact skin • Linings of body cavities and tubes Innate immune system • General, immediate response to antigens • Does not target specific intruders Adaptive immune system
    6. 6. We Are Born with Some General Defensesand Acquire Other, Specific Ones (1) Pathogens • Viruses • Bacteria • Fungi • Protozoa • Parasitic worms Antigens • Proteins • Lipids • Oligosaccharides
    7. 7. We Are Born with Some General Defensesand Acquire Other, Specific Ones (2) Immunity • Innate immunity • Preset responses • Immediate response • Carried out by some white blood cells and plasma proteins • Adaptive immunity • Slower response • Carried out by lymphocytes and proteins • Every adaptive response leaves behind cells that “remember” a pathogen  basis of immunizations
    8. 8. White Blood Cells The defendersProduced by stem cells in bone marrow
    9. 9. Phagocytes Type of WBC Releases several types of cytokines • “Cell movers” that promote and regulate immunity • Interleukines • Interferons
    10. 10. White Blood Cells & Their Chemicals Arethe Defenders in Immune Responses (1) Phagocytic white blood cells release chemical signals and aid the immune system • Cytokines • Interleukins • Interferons • Tumor necrosis factor • White blood cell enzymes Another chemical weapon • Complement system (proteins) • ~30 proteins • Act as antimicrobials- flag microbes for destruction!
    11. 11. White Blood Cells & Their Chemicals Arethe Defenders in Immune Responses (2) Types of white blood cells: Neutrophils (2/3rds of our WBC’s) Basophils (release histamines) Mast cells (release histamines) Macrophages (engulf cells) Eosinophils (target worms, fungi, etc) Dendritic cells (alert immune system when antigen is in tissue fluid in skin and body linings B and T Lymphocytes • B cells and T cells: only cells with specific receptors Natural killer cells (NK cells- destroy cancer cells & cells infected by viruses
    12. 12. The Lymphatic System Lymphatic system • Picks up fluid lost from the capillaries and returns it to the blood • Defense • Consists of: drainage vessels, lymphoid organs, and lymph tissues Lymphoid organs • Spleen • Lymph nodes • Others Lymph  Fluid identical to interstitial fluid
    13. 13. Lymphatic System Elephantiasis • A condition in which parasites block lymphatic vessels, preventing the return of fluid to blood • Results in massive swelling, darkening, and thickening of the skin in the affected area
    14. 14. Lymphatic System  Components of the lymphatic system • Lymph • Fluid identical to interstitial fluid • Lymphatic vessels • Vessels through which lymph flows • Have one-way valves to prevent backflow • Lymphoid tissues and organs
    15. 15. TonsilsDefense against bacteria and other foreign agentsRight Lymphatic DuctDrains right upper portion of the bodyThymus GlandSite where certain white blood cells acquire meansto chemically recognize specific foreign invadersThoracic DuctDrains most of the bodySpleenMajor site of antibody production; disposal site forold red blood cells and foreign debris; site of redblood cell formation in the embryoSome Lymph VesselsReturn excess interstitial fluid and reclaimablesolutes to the bloodSome Lymph NodesFilter bacteria and many other agents of diseasefrom lymphBone MarrowMarrow in some bones is production site forinfection-fighting blood cells (as well as red blood Stepped Artcells and platelets) Fig. 9-2, p. 158
    16. 16. The Lymph Vascular System Functionsin Drainage, Delivery, and Disposal Lymph capillaries at the start of the drainage network • Collect water & solutes Merge into larger vessels containing smooth muscles and valves Transport material to ducts of CV system
    17. 17. Lymph Capillaries Collect Fluid andDirect It through Lymph Nodes
    18. 18. Lymph Lymph fluid returns to blood via large lymph vessels that drain into veins in the lower neck
    19. 19. Lymphoid Organs and Lymphatic TissuesAre Specialized for Body Defense Lymph nodes • Lymphocytes and macrophages clear the lymph of bacteria and other foreign substances Spleen • largest lymphatic organ • Filters blood • Major site of antibody production • Storage reservoir of red blood cells and macrophages Thymus • Site of T cell multiplication and specialization
    20. 20. Take Home• What are the functions of the lymphatic system?
    21. 21. Surface BarriersPathogens usually cannot getpast the skin or the linings ofother body surfaces such as the digestive tract
    22. 22. Surface Barriers (1) Bacteria are normal inhabitants of the body • Roles of bacteria • On the skin • In the mucosal lining of the digestive tract • In the vaginal mucosa, e.g., Lactobacillus Effect of antibiotics on normal microbial inhabitants, e.g., Lactobacillus Athlete’s foot
    23. 23. Vaginal Yeast Infection
    24. 24. Surface Barriers (2) Inner walls of the respiratory airways • Sticky mucus • Cilia • Lysozyme • Enzyme that fights bacteria More protection found in: • Tears • Saliva • Gastric fluid • Urine has low pH and flushing action • Mild diarrhea
    25. 25. Innate Immunity Phagocytosis, …inflammation, …and fever… …are the body’s “off-the-shelf” mechanisms that act at once to counter threats in general and prevent infection
    26. 26. The Mighty Macrophage!
    27. 27. Innate Immunity (1) Once a pathogen enters the body: Macrophages arrive 1st (usually) • Release cytokines if they detect antigen • Cytokines are chemical signals that attract dendritic cells, neutrophils, and more macrophages Complement molecules activated • Attract phagocytes (such as macrophages & neutrophils) • Bind to the pathogen • May form membrane attack complexes • Trigger inflammation
    28. 28. Inflammatory Response Inflammatory response • Destroys invaders and helps repair and restore damaged tissue • Four signs • Redness • Heat • Swelling • Pain
    29. 29. Inflammatory Response Redness • Mast cells release histamine, which causes blood vessels to dilate • Blood flow to the area increases, delivering defensive cells and removing dead cells and toxins
    30. 30. Inflammatory Response Heat • Temperature rises as a result of increased blood flow • Speeds healing and activities of defensive cells
    31. 31. Inflammatory Response Fever • An abnormally high body temperature • Caused by pyrogens • Chemicals that reset the brain’s thermostat to a higher temperature • A mild or moderate fever helps fight bacterial infection • A very high fever (over 105°F or 40.6°C) is dangerous
    32. 32. Inflammatory Response Swelling • Histamine causes capillaries to become leaky and fluid seeps into tissues • Fluid brings clotting factors, oxygen, and nutrients
    33. 33. Inflammatory Response Pain • Can be caused by • Excess fluid • Bacterial toxins • Prostaglandins
    34. 34. Acute sudden inflammation Activated complement and cytokines trigger this fast, general response to tissue invasion Symptoms are redness, swelling, warmth, and pain, all caused by this series of internal events 
    35. 35. Acute Inflammation Is a GeneralResponse to Tissue Damage Histamines ↑
    36. 36. Innate Immunity (2) Symptoms of inflammation include redness, swelling, warmth, and pain Internal events of inflammation • Mast cells release histamine • Arteriole vasodilation • Fluid and plasma leak out of capillaries leading to edema (swelling) • Bacteria attacked • Clotting factors- wall off inflamed area • Fever- develops when cytokines stimulate brain to release prostaglandins • Prostaglandins are signaling molecules that raise set point on hypothalamic thermostat
    37. 37. Adaptive Immunity
    38. 38. Overview of Adaptive Defenses When physical barriers and inflammation don’t prevent an invasion, the adaptive immune system is mobilized
    39. 39. Adaptive Immunity Has Three Key Features Adaptive immunity mobilizes B and T cells 1. Specificity- receptors for 1 kind of antigen form 2. Diversity- collectively, these cells may have receptors for ~a billion different specific threats 3. Memory- some of the B and T cells are held in reserve for future battles Effector cells • Respond immediately to destroy pathogen Memory cells • Set aside for a second or third encounter
    40. 40. Distinguishing Self from Nonself T cells and B cells • B cells and T cells that respond to a particular antigen divide repeatedly, forming two cell lines • Effector cells • Short-lived cells that attack the invader • Memory cells • Long-lived cells that remember the invader and mount a quick response when it is next encountered
    41. 41. Activated Lymphocytes Produce EffectorCells and Memory Cells
    42. 42. Antibody-Mediated Responses and Cell-Mediated Responses
    43. 43. B Cells and T Cells Attack Invaders inDifferent Ways B cells • Produced in bone marrow, sent to lymphatic system • Produce antibodies; antibody-mediated immunity- instead of direct engagement, produce protein antibodies T cells • Produced in bone marrow and go to the thymus gland for development • Cytotoxic T cells; cell-mediated immunity- involves direct engagement • Helper T cells- have both types of responses
    44. 44. Steps of the Adaptive Immune Response1. Threat • Foreign organism or molecule (an antigen) enters the body2. Detection • Macrophage detects foreign organism or molecule and engulfs it
    45. 45. Steps of the Adaptive Immune Response3. Alert • Macrophages present antigens to helper T cells • Macrophages are antigen-presenting cells • Helper T cells are the main switch for the adaptive immune response
    46. 46. Steps of the Adaptive Immune Response4. Alarm • Helper T cells activate appropriate B cells and T cells to destroy the specific antigen • When activated, these cells divide to form clones of cells designed to eliminate the specific antigen from the body
    47. 47. Steps of the Adaptive Immune Response5. Building specific defenses • B cells form plasma cells that secrete antibodies into the bloodstream that bind to antigens • T cells form cytotoxic T cells that attack
    48. 48. Steps of the Adaptive Immune Response6. Defense: The cell-mediated response • An effector cytotoxic T cell releases perforins, which cause holes to form in cells with the particular antigen
    49. 49. Steps of the Adaptive Immune Response 7. Continued surveillance  Immunological memory allows for a more rapid response on subsequent exposure to the antigen  Primary response  Occurs during body’s first encounter with a particular antigen  Antibody concentration rises slowly  Secondary response  Occurs during subsequent encounter with that antigen  Strong and swift due to the large number of memory cells programmed to respond to that particular antigen
    50. 50. B and T Cells
    51. 51. B & T Cells When mature, most move into lymph nodes, the spleen, and other lymphoid tissue Remember- two different responses occur: 1) Antibody- mediated 2) Cell-mediated
    52. 52. How Do B & T Cells Learn? They study hard! • Study groups • Biojeopardy learning games Involves MHC markers • Major histocompatability complex genes
    53. 53. MHC Markers Label Body Cells as Self MHC markers • Major Histocompatibility Complex genes code for these proteins • Some of these proteins stick out of cell membranes • T cells have receptors that recognize them
    54. 54. Antibody-Mediated Immunity: Defendingagainst Threats Outside Cells Different kinds of antibodies have roles in body defenses 5 classes of antibodies
    55. 55. Antibodies Develop While B Cells Are in Bone Marrow B cell in bone marrow develops antibodies Binding of antigens • Copies of antibodies made by B cell, migrate to and stick out of plasma membrane like ‘bristles’
    56. 56. Antibodies Can Bind to Antigens antigen on bacterialbinding site for antigen binding site for antigen cell (not to scale) binding site on one kind of antibody molecule for a specific antigen Typical Y-shape of simple antibody Stepped Art Fig. 9-12, p. 164
    57. 57. There Are Five Classes of Antibodies,Each with a Particular Function Immunoglobulins (Igs) • Proteins produced by B cells; various shapes • Result from gene shuffling while B cell matures during immune response • Antigen-binding sites; other sites with special roles Types of Igs (pg165) • IgM • IgD • IgG • IgA • IgE
    58. 58. Cell-Mediated Responses: Defendingagainst Threats Inside Cells Responses by antibodies can’t reach threats inside cells Accordingly, when cells become infected or altered in harmful ways, other “warrior” cells must come to the defense
    59. 59. Cell-Mediated Responses Starts when an antigen presenting cell (APC) presents an antigen to a T cell Role of: • Helper T cells and cytotoxic T cells  specific response • NK cells and macrophages  more general response Target: viruses, bacteria, some protozoa and some fungi, and cancerous cells Apoptosis
    60. 60. ProtozoansGiardiasis is an infection of the smallintestine caused by a microscopicorganism (protozoa), Giardia lamblia.Abdominal pain, Diarrhea, Gas or bloating,Headache, Loss of appetite, Low-gradefever, Nausea, Swollen or distendedabdomen, Vomiting
    61. 61. T Cells Are the Warriors in Cell-MediatedImmune Responses
    62. 62. T cell (orange) killing a cancer cell(magenta).
    63. 63. Helper T Cells Their cytokines stimulate NK cells NK cells don’t need an antigen They simply attack any body cell that has too few or altered MHC markers, or that antibodies have tagged for destruction They also kill cells flagged with chemical “stress markers” that develop when a cell is infected or becomes cancerous
    64. 64. A Cytotoxic T Cell Touch-Killing aTumor Cell Release chemicals that kill on contact. Also release chemicals that cause genetically programmed cell death- apoptosis.
    65. 65. Cytotoxic T Cells Cause the Body toReject Transplanted Tissue MHC markers on donor cells recognized as antigens by recipient cells Best donors have similar genetic makeup and compatible blood type with recipient Recipient takes immuno-suppressing drugs and often antibiotics to control infections Transplanted tissues of the eye and testicles do not provoke an immune response
    66. 66. Immunological Memory The memory cells produced during an adaptive immune response can provide many years of immunity to a pathogen
    67. 67. Immunological Memory Memory cells form during primary (first) immune response • Circulate for years, even decades • Patrolling battalions Even more memory T and plasma cells form during a second adaptive response Memory cells determined by the type of antigen exposure
    68. 68. Memory Cells Allow the Body to Mount aFaster, Stronger Immune Response
    69. 69. Applications of Immunology Modern science has developed powerful weapons that can enhance the immune system’s functioning or harness it in new ways to treat disease Vaccine  primary immune response to antigen Booster  secondary immune response; more effector & memory cells form that can provide longer lasting protection
    70. 70. Immunization Gives “Borrowed”Immunity Immunization • Vaccine: first injection + “booster shot” • Killed or extremely weakened pathogens • Inactive forms of natural toxins • Transgenic viruses Passive immunization • Injections of purified antibodies • Does not confer memory cells though Adverse effects of vaccines
    71. 71. Passive Immunity to Infectious Disease1955
    72. 72. WHO: Prevent. Protect. Immunize.
    73. 73. Disorders of the Immune System In allergies, harmless substances provoke an immune attack
    74. 74. In Allergies, Harmless SubstancesProvoke an Immune Attack (1) Common allergens • Pollen • Variety of foods and drugs • Dust mites • Fungal spores • Insect venom • Ingredients in cosmetics Allergy • Response and severity
    75. 75. The Basic Steps Leading to an AllergicResponse Role of IgE antibodies
    76. 76. In Allergies, Harmless SubstancesProvoke an Immune Attack (2) Symptoms of allergies vary • Inflammation of mucus membranes • Constriction of airways • Stuffed sinuses, drippy nose, and sneezing in hay fever • Vomiting • Diarrhea Anaphylactic shock • Whole-body allergic response • Can be fatal
    77. 77. Autoimmune Disorders Attack “Self” Autoimmune disorders • Rheumatoid arthritis • Type I diabetes • Insulin secreting cells of pancreas attacked • Systemic lupus erythematosus Immune systems “weapons” unleashed upon own body More common in women- is receptor for estrogen involved??
    78. 78. Immune Responses Can Be Deficient Immunodeficiency • Weakened or missing immune system Severe combined immune deficiency (SCID) • Short supply of B and T cells • Usually inherited • Usually infants die early HIV and AIDS
    79. 79. HIV and AIDS HIV, the human immunodeficiency virus, cripples the immune system by destroying lymphocytes
    80. 80. HIV and AIDS AIDS caused by infection with HIV HIV kills lymphocytes • Macrophages, dendritic cells, and helper T cells • Can get in via certain type of surface receptor Diagnostic signs of AIDS • Severely depressed immune system • Positive HIV test • “Indicator disease”- types of pneumonia, recurrent yeast infections, cancer, drug-resistant TB
    81. 81. Particles bursting the cell membrane
    82. 82. HIV Life Cycle
    83. 83. Pathogens Spread in Four WaysInfections that can threaten health spread in 4 predictable ways and occur in 4 predictable patterns1. Direct contact2. Indirect contact3. Inhaling pathogens4. Contact with a vector Nosocomial infection: acquired in a hospital
    84. 84. Many Infections Are Spread by Contactor When a Pathogen Is Inhaled
    85. 85. Diseases Occur in Four Patterns Epidemic • Disease rate increases to a level above what we would predict Pandemic • When epidemics break out in several countries around the world Sporadic disease • Irregularly breaks out and affects relatively few Endemic disease • Occurs more or less continuously
    86. 86. Virulence Is a Measure of PathogenDamage Virulence of a pathogen How fast can the pathogen invade the tissues? How severe is the damage it causes? Which tissues are targeted?
    87. 87. Respiratory tractPreventative measures:• Hand washing• Cover mouth when coughing orsneezing• Proper disposal of used tissues• Vaccination programsGI tractPreventative measures:• Hand washing• Proper food storage, handling, andcooking• Good public sanitation (sewage,drinking water)BloodPreventative measures:• Avoid/prevent needle sharing/ IV drugabuse• Maintain pure public blood supplies• Vaccination programs against blood-borne pathogens (e. g., hepatitis B)SkinPreventative measures:• Hand washing• Limit contact with items used by aninfected person Fig. 9-25a, p. 175
    88. 88. The Human Body’s Three Lines of Defense againstPathogens
    89. 89. Introduction to how the immune systemworks | Biology | Anatomy | Immunology
    90. 90. Cell Mediated Immune Response
    91. 91. Antibody Mediated Immune Response