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 animationphagocytosis animation  Natural killer cells  Inflammatory response leukocyte rolling animationleukocyte rolling animation  Antimicrobial chemicals  Complement  Interferons interferon animationinterferon 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