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Lymphatic System & Body Defenses. Anatomy and Physiology II Mrs. Harborth. Lymphatic System. Made of: Lymphatic vessels Lymphatic tissues and organs. Lymphatic Vessels. Pick up excess fluid (lymph) in the tissues and returns it to bloodstream Flows only toward the heart
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Lymphatic System &Body Defenses Anatomy and Physiology II Mrs. Harborth
Lymphatic System • Made of: • Lymphatic vessels • Lymphatic tissues and organs
Lymphatic Vessels • Pick up excess fluid (lymph) in the tissues and returns it to bloodstream • Flows only toward the heart • Vessels lead to one of 2 large ducts • Right lymphatic duct • Thoracic duct
Lymph Nodes • Remove foreign material from lymphatic stream and produce lymphocytes • Most are kidney-shaped, less than an inch long • Cortex • Follicles • Germinal Centers • Plasma cells • Medulla
Lymphoid Organs • Lymph nodes • Spleen • Thymus gland • Tonsils • Peyer’s patches on intestines
Body Defenses • Nonspecific vs Specific defense systems
Nonspecific Body Defenses • Mechanical barriers • Cells • Chemicals
Cells and Chemicals • Phagocytes phagocytosis animation • Natural killer cells • Inflammatory response leukocyte rolling animation • Antimicrobial chemicals • Complement • Interferons interferon animation • Fever • Pyrogens • Iron and zinc gathered by liver/spleen
Specific Body Defenses:Immune Response • Functional system that recognizes foreign molecules (antigens) and inactivates or destroys them • Humoral (antibody-mediated) or cellular (cell-mediated) Immunity • 3 aspects of immune system: • 1. Antigen specificity • 2. Systemic • 3. Has “memory”
Antigens • Foreign proteins, nucleic acids, large carbs, some lipids • Self-antigens • Hapten (incomplete-antigen)
Lymphocytes • Originate from hemocytoblasts in red bone marrow • B cells become immunocompetent in bone marrow • T cells become immunocompetent in the thymus • Once immunocompetent, only reacts to one distinct antigen • Genetic determinance
Macrophages • Arise from monocytes in bone marrow • Engulf foreign particles and present fragments of antigens on surfaces where T cells “read” them • Monokines • Killer macrophages • Stay in lymphoid organ
Humoral Immune Response • B Lymphocytes undergo clonal selection • Plasma cells (antibody levels peak at 10 days) • Memory cells
Active Immunity • B cells encounter antigens and produce antibodies • Naturally acquired or artificially acquired
Passive Immunity • Antibodies come from outside source (animal or human) • Fetal circulation or immune serum • Monoclonal antibodies
Antibodies • IgM, IgA, IgD, IgG, IgE • Complement fixation • Neutralization • Agglutination • Precipitation
Cellular Immune Response • Antigen presentation (macrophages and T cells) • Interleukin 1 • Helper T cells, Cytotoxic T cells, Suppresor T cells, Delayed hypersensitivity T cells, memory cells
Organ Transplantation/Rejection • Autografts • Isografts • Allografts • Xenografts
Allergies • Immediate hypersensitivity • Delayed hypersensitivities
Immunodeficiencies • SCID • AIDS
Autoimmune Diseases • MS • Myasthenia gravis • Grave’s disease • Juvenile diabetes mellitus • Systemic lupus erythematosus • Glomerulonephritis • Rheumatoid Arthritis