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M6 13-005
Exam 14: Immune System
Term | Definition |
---|---|
Three functions of the immune system | Protect internal environment. Maintain homeostasis by removing damaged cell. Network for recognizing and guarding against the development and growth of abnormal cells. |
Natural immunity (Innate immunity): | Body's first line of defense. Provides physical and chemical barriers to invading pathogens. Protects against external environment. Skin, mucous membranes, cilia, stomach, flora etc. Provides non-specific immunity. |
Acquired immunity (Adaptive immunity): | 2nd line of defense. Starts when natural immunity is unable to prevent. Protects internal environment. Special cells and tissues. Specific immunity. Ability to remember antigen that caused attack. Hormonal & cellular immunity. |
Physical Barriers | Physical defense: skin and mucous membranes line body cavities such as the mouth and stomach. These cavities secrete chemicals that destroy bacteria. Cilia, tears, and secretions and flora of the intestine and vagina also provide natural protection. |
Response Mechanisms | Nonspecific: mononuclear phagocytic system; inflammatory response. Adapts: Specific immune response humoral immunity, cellular immunity. |
Soluble factors | Chemical defense: Lysozyme, complement, acute phase proteins, interferon. Adapts: Antibodies, lymphokines |
Cells | Phagocytes, natural killer (NK) cells. Adapts: T lymphocytes, B lymphocytes. |
Humoral immunity | Form of immunity that responds to antigens such as bacteria and foreign tissue. |
Humoral immunity is mediated by.. | B cells. |
what do B-cells do? | produce antibodies in response to antigen challenge. |
How do B-cells work? | Primary humoral response initiated on first exposure to an antigen. First response is slow compared to subsequent antigen exposure. 2nd time, memory B cells cause a quick response regardless of whether the first exposure was to antigen or immunization. |
T-helper cells (CD4) | 1) Assist B cells to proliferate, synthesize, and secrete the appropriate antibody. 2) Antigens are then neutralized by antibodies or can form immune complexes or can be phagocytosed by macrophages or neutrophils. |
Cell-mediated immunity (cellular immunity): | The mechanism of acquired immunity characterized by the dominant role of small T cells, results when T cells are activated by an antigen. |
Cell-mediated immunity (cellular immunity): protects against | (a) Viruses and some bacteria. (b) Fungal infections. (c) Rejection of transplanted tissues (allograft). (d) Contact hypersensitivity reactions. (e) Tumor immunity (malignant cells). (f) Certain autoimmune diseases |
Cell-mediated immunity (cellular immunity): MOA | (a) Antigen is processed by macrophages and recognized by T cells. (b) T cells produce lymphokines. (c) Lymphokines attract macrophages and neutrophils to the site for phagocytosis, or cytotoxic killer T cells can respond directly. |
Aging decline in immune system | Thymus ↓ in size. Bone marrow unaffected. Immune system keeps producing antibodies. |
Immunocompetent: | (1) An individual with an immune system that has the ability to mobilize and deploy its antibodies and other responses to stimulation by an antigen. (2) Normal functioning immune system. (3) Immune system protects the body. |
Immunodeficient: | Abnormal cellular or humoral immunity is inadequate and resistance to infection is decreased. Immunodeficiency diseases are classified as T-cell (cellular) and combined T- and B- cell deficiencies. Does not invading antigen. |
Autoimmunity: | Development of an immune response to one's own tissues. Autoantibodies or cellular immune response. Abnormally functioning immune response - immune system fails to distinguish "self" protein from "foreign" protein. Causes pathophysiologic tissue damage |
Hypersensitivity disorder: | Inappropriate and excessive response of the immune system to a sensitizing antigen. |
Hypersensitivity disorder: Factors that influence | 1) Host response to allergen. 2) Exposure amount. 3) Nature of allergen. 4) Route of allergen entry. 5) Repeated exposure. |
Hypersensitivity disorder: Subjective data | pruritus, nausea, and uneasiness |
Hypersensitivity disorder: Objective data | includes sneezing, excessive nasal secretions, lacrimation, inflamed nasal membranes, skin rash or areas of raised inflammation, diarrhea, cough, wheezes, impaired breathing, and hypotension. |
Hypersensitivity disorder: Dx Tests | 1) Complete Blood Count (CBC). 2) Skin testing. 3) Total serum IgE levels. 4) RAST (radioallgergosorbent test). |
Immunodeficiency disease | ↑ susceptibility to infection. Manifest as recurrent infection or chronic infection. Unusually severe infection w/ complications or incomplete clearing of an infection may also indicate an underlying immunodeficiency. May be hereditary (defects in genes) |
Immunodeficiency disease: Involves an impairment of one or more immune mechanisms. | (a) Phagocytosis. (b) Humoral response. (c) Cell-mediated response. (d) Complement. (e) Combined humoral and cell-mediated deficiency. |
Immunodeficiency disease: Primary | 1) Rare and often serious. 2) Immune cells are improperly developed or absent. -Phagocytic defects. -B-cell deficiency. -T-cell deficiency. -Combined B-cell and T-cell deficiency. |
Immunodeficiency disease: Secondary | 1) More common and less serious. 2) Deficiency caused by illness or treatment. -Drug-induced. -Stress. -Hypofunctional state. -Malnutrition. -Surgical removal of lymph nodes. -Hodgkin's disease. |
Autoimmune disease | Immune cells that are normally unresponsive (tolerant to self-antigens) are activated. Alteration can occur only in T-cells or may be in both B-cells and T-cells The alterations results in a production of autoantibodies and in autosensitized T cells. |
Conditions thought to be autoimmune | Pernicious anemia. Guillain-Barre syndrome. Scleroderma. Jorgen's syndrome. Rheumatoid arthritis. Ulcerative colitis. Male infertility. Myasthenia gravis. Multiple sclerosis. Systemic lupus erythematosus. Type I diabetes mellitus. |
Transfusion Reactions | Transfusion reactions are a hypersensitive disorder. Most serve reactions occur within 15 min, moderate reactions occur within 30-90 min and mild reactions may be delayed to late in the transfusion or hours to several days |
Transfusion Reactions: Signs | a. Dermatitis b. Fever c. Chills d. Urticaria e. Cough |
Treatment of Transfusion Reactions | a. Stopping the transfusion b. Administering Saline c. Steroids d. Antihistamines e. Epinephrine |
Treatment of Transfusion Reactions: fun facts | In the case of a transfusion reaction the blood product and tubing must be returned to the lab for testing if any type of reaction occurs. Preventing transfusion reaction requires careful blood typing and proper administration of blood products. |
lupus erythematosus | Autoimmune disorder characterized by inflammation of almost any body part. Occurs when the body produces antibodies against its own cells. T suppressor cells are ↓ in # and function. |
lupus erythematosus: Manifestations | Oral ulcers. Arthralgias or arthritis. Vasculitis. Rash. Nephritis. Pericarditis. Synovitis. Organic brain syndromes. Peripheral neuropathies. Anemia Leukopenia Thrombocytopenia Immunosuppression Dermatitis Anemia is the most common complica |
lupus erythematosus: Dx Tests | ANA, DNA Antibody, CBC, ESR, Sed., Coag, RF, RPR, Skin & Renal Bx, CRP, Coomb's, LE cell Prep, UA, chest radiography |
lupus erythematosus: criteria | Positive ANA and 3 others. |
lupus erythematosus: Drug Therapy | NSAIDs, ASA, Anti-malarial, Corticosteroids, Anti-nepoplastics, anti-infectives, analgesics & diuretics |
Plasmapheresis | removal of plasma that contains components causing or thought to cause disease. |
Plasmapheresis: Used for | (a) Systemic lupus erythematosus. (b) Glomerulonephritis. (c) Myasthenia gravis. (d) Thrombocytopenic purpura. (e) Rheumatoid arthritis (f) Guillain-Barre syndrome. |
Plasmapheresis removes pathologic substances present in plasma... Which ones? | (a) Antinuclear antibodies (autoantibody). (b) Antigen - antibody complexes. (c) Inflammatory mediators (complement system). |
Plasmapheresis: How much blood at a time? | 500mL |
Plasmapheresis: Most common complications | hypotension. Citrate Toxicity |
Plasmapheresis: Hypotension results from | Vasovagal reaction. Transient volume changes. |
Plasmapheresis: Citrate toxicity | a) Citrate is used as an anti-coagulant and may cause hypocalcemia. b) Signs and symptoms include headache, paresthesias and dizziness. |