PowerPoint Lecture Outlines Immunology
Chapter 16 Lymphatic System and Immunity
• network of vessels that assist in circulating fluids • transports excess fluid away from interstitial spaces • transports fluid to the bloodstream • transports fats to bloodstream • help defend the body against diseases
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Lymphatic Pathways
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Lymphatic Pathways
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Lymphatic Capillaries
• microscopic • closed-ended tubes • in interstitial spaces of most tissues
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Lymphatic Vessels
• merge into lymphatic trunks • lymphatic trunks drain into collecting ducts
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Lymphatic Ducts
• Right lymphatic duct
• Thoracic duct
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Tissue Fluid and Lymph
Lymph • tissue fluid that has entered a lymphatic capillary
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Lymph Function
• absorption of dietary fats • delivers fats to bloodstream • collection of excess interstitial fluids • delivers excess fluids to bloodstream • delivers foreign particles to lymph nodes
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Lymph Movement
• action of skeletal muscles • respiratory movements • smooth muscle in larger lymphatic vessels • valves in lymphatic vessels
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Lymph Nodes
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Lymph Nodes
• cervical region • axillary region • inguinal region • pelvic cavity • abdominal cavity • thoracic cavity • supratrochlear region
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Functions of Lymph Nodes
• filter potentially harmful particles from lymph • immune surveillance by macrophages and lymphocytes • areas of lymphocyte production
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Thymus
• small in an adult • site of T lymphocyte production • secretes thymosins
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Spleen
• largest lymphatic organ • upper left abdominal quadrant • sinuses filled with blood • white pulp • lymphocytes • red pulp • red blood cells • lymphocytes • macrophages
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Body Defenses Against Infection
• pathogen
• disease causing agent • bacteria, viruses, etc
• innate defenses
• general defenses • protects against many pathogens
• adaptive defenses
• immunity • more specific • carried out by lymphocytes
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Innate Defenses
• Species Resistance
• resistance to certain diseases to which other species are susceptible
• Fever
• inhibits microbial growth • increases phagocytic activity
• Mechanical Barriers
• skin • mucous membranes
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Innate Defenses
• Chemical Barriers
• enzymes in various body fluids • pH extremes in stomach • high salt concentrations • interferons • defensins • collectins
• Natural Killer Cells
• type of lymphocyte • lysis of viral-infects cells and cancer cells
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Innate Defenses
• Inflammation
• tissue response to injury • helps prevent spread of pathogen • promotes healing • blood vessels dilate • capillaries become leaky • white blood cells attracted to area • clot forms • fibroblasts arrive • phagocytes are active
• Phagocytosis
• neutrophils • monocytes • macrophages • destruction of foreign particles
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Immunity
• resistance to particular pathogens or to their toxins or metabolic by-products • based on the ability to distinguish “self” from “non-self” • antigens elicit immune responses
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Antigens
• proteins • polysaccharides • glycoproteins • glycolipids • most effective are large and complex • haptens are small molecules that are not antigenic by themselves
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Lymphocyte Origins
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Lymphocyte Functions
• T cells • secrete lymphokines
• help activate T cells • cause T cell proliferation • activate cytotoxic T cells • stimulate leukocyte production • stimulate B cells to mature • activate macrophages
• secrete toxins that kill cells • secrete growth-inhibiting factors • secrete interferon • cellular immune response
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Lymphocyte Functions
• B cells • differentiate into plasma cells
• produce antibodies
• humoral immune response
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T Cells
• requires antigen-presenting cell • requires MHC antigens • types of T cells • helper T cell • cytotoxic T cell • memory T cell
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T Cell and B Cell Activation
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B Cell Proliferation
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Antibody Molecules
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Types of Immunoglobulins
IgG • located in tissue fluid and plasma • activates complement • defends against bacteria, viruses, and toxins
IgA • located in exocrine gland secretions • defends against bacteria and viruses
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Types of Immunoglobulins
IgM • located in plasma • reacts with naturally occurring antigens on RBCs following certain blood transfusions • activates complement IgD • located on surface of most B lymphocytes • plays a role in B cell activation IgE • located in exocrine gland secretions • promotes inflammation and allergic reactions
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Antibody Actions
• agglutination • precipitation • neutralization • activation of complement
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Actions of the Complement System
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Immune Responses
A primary immune response produces a lesser concentration of antibodies than does a secondary immune response
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Practical Classification of Immunity
• Naturally acquired active immunity • Artificially acquired active immunity • Naturally acquired passive immunity • Artificially acquired passive immunity
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Allergic Reactions
Type I • immediate-reaction allergy • hives • hay fever • asthma • eczema • gastric disturbances • anaphylactic shock
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Allergic Reactions
Type II • antibody-dependent cytotoxic reaction • takes 1-3 hours to develop • transfusion reaction Type III • immune-complex reaction • takes 1-3 hours to develop • antibody complexes cannot be cleared from body • damage of body tissues
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Allergic Reactions
Type IV • delayed-reaction allergy • results from repeated exposure to allergen • eruptions and inflammation of the skin • takes about 48 hours to occur
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Transplantation and Tissue Rejection
• corneas • kidneys • livers • pancreases • hearts • bone marrow • skin Tissue rejection reaction • resembles cellular immune response against antigens • important to match MHC antigens • immunosuppressive drugs used to prevent rejection
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Graft Types
• Isograft – identical twin • Autograft - self • Allograft – same species • Xenograft – different species
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Autoimmunity
• inability to distinguish “self” from “non-self” Autoimmune Disorders • glomerulonephritis • Graves disease • type I diabetes • hemolytic anemia • myasthenia gravis • rheumatic fever • rheumatic arthritis • lupus
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Life-Span Changes
• immune system declines early in life when thymus gland shrinks • higher risk of infections • antibody response to antigens becomes slower • IgA and IgG antibodies increase • IgM and IgE antibodies decrease
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Clinical Application
Immunity Breakdown: AIDS
• recurrent fever • weakness • weight loss • caused by HIV (human immunodeficiency virus) • HIV impair macrophages and helper T cells • later in infection, HIV impairs cytotoxic T cells • HIV mutates quickly • immune system cannot keep up with HIV
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