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Chapter 16Lymphatic System and
Immunity
• vessels that assist in circulating fluids• • transports fluid to the bloodstream• transports fats to bloodstream•
16-2
Lymphatic Pathways
16-3
Lymphatic Pathways
16-4
Lymphatic Capillaries
• microscopic• closed-ended tubes• in interstitial spaces of most tissues
16-5
Lymphocytes.mov
Lymphatic Vessels
• merge into lymphatic trunks• lymphatic trunks drain into collecting ducts
16-6
Tissue Fluid and Lymph
Lymph• tissue fluid that has entered a lymphatic capillary
16-8
Spleen
• largest lymphatic organ• upper left abdominal quadrant• sinuses filled with blood
16-15
Body Defenses Against Infection
• pathogen• • bacteria, viruses, etc
• innate defenses • general defenses•
• adaptive defenses• immunity• • carried out by lymphocytes
16-16
Innate Defenses
• Species Resistance• resistance to certain diseases to which other species are susceptible
• Mechanical Barriers• skin• mucous membranes
• Fever •
• increases phagocytic activity
16-17
Innate Defenses
• Chemical Barriers• enzymes in various body fluids• • • interferons• defensins• collectins
• Natural Killer Cells• type of lymphocyte• lysis of viral-infects cells and cancer cells
16-18
Innate Defenses
• Inflammation• response to injury• • promotes healing• blood vessels dilate• • white blood cells attracted to area• clot forms• fibroblasts arrive• phagocytes are active
• Phagocytosis• neutrophils• monocytes• macrophages• destruction of foreign particles
16-19
Nonspecific Immunitiy.movMachrophage.mov
Fevor.movInterferion.mov
Immunity
• resistance to particular pathogens or to their toxins or metabolic by-products• • antigens elicit immune responses
16-20
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
16-23
T cells.mov
Lymphocyte Functions
• B cells• differentiate into plasma cells
• produce antibodies
16-24
T Cells
•types of T cells• T cell• T cell• T cell
16-25
T Cell and B Cell Activation
16-26
B Cell Proliferation
16-27
Antibody Actions
• agglutination• precipitation• neutralization• activation of complement
16-31
Antibodies.mov
Actions of the Complement System
16-32Vacination.mov
Allergic Reactions
Type I• • hives• hay fever• asthma• eczema• gastric disturbances• anaphylactic shock
16-35
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
16-36
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
16-37
Transplantation and Tissue Rejection
• corneas• kidneys• livers• pancreases• hearts• bone marrow• skin
Tissue rejection reaction•
• important to match MHC antigens•
16-38
Graft Types
• Isograft – identical twin• Autograft - self• Allograft – same species• Xenograft – different species
16-39
Autoimmunity
•
Autoimmune Disorders• glomerulonephritis• Graves disease• type I diabetes• hemolytic anemia• myasthenia gravis• rheumatic fever• rheumatic arthritis• lupus
16-40
Life-Span Changes
• immune system declines early in life when thymus gland shrinks• higher risk of infections• antibody response to antigens becomes slower
16-41
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
16-42