NR507 Pathophysiology Midterm Questions & Answers

Active immunity - ANSWERSproduced by an individual either after natural exposure to an antigen or after immunization Passive immunity - ANSWERSoccurs when preformed antibodies or T lymphocytes are transferred from a donor to the recipient *can occur naturally: passage of maternal antibodies across the placenta to the fetus *artificially: in a clinic using immunotherapy for a certain disease *temporary, the donor antibodies or T cells are eventually destroyed Innate immunity - ANSWERSAlso known as natural or native immunity The natural epithelial barrier and inflammation confer innate resistance and protection Adaptive immunity - ANSWERSinflammation associated with infection usually initiates an adaptive process that results in long-term and very effective immunity to the infecting microorganism *slow to develop but has memory and more rapidly targets and eradicates a second infection with a particular disease causing microorganism natural barriers - ANSWERSphysical, mechanical and biochemical barriers at the body's surfaces and are in place at birth to prevent damage by substances in the environment and thwart infection by pathogenic microorganisms Inflammatory response - ANSWERS*second line of defense activated to protect the body from further injury, prevent infection of injured tissue, and promote healing *rapid activation of biochemical and cellular processes that is relatively nonspecific, with similar responses being initiated against a wide variety of causes of tissue damage Hypersensitivity - ANSWERSan altered immunologic response to an antigen that results in disease or damage to the individual *classified in two ways: by the source of the antigen that the immune system is attacking; and by the mechanism that causes disease Type 1: IgE-Mediated Hypersensitivity Reactions - ANSWERSMediated by antigen-specific IgE and the products of tissue mast cells *mast cell degranulation leads to an inflammatory response Mediators for Type 1 hypersensitivity reaction - ANSWERS*Histamine: contracts bronchial smooth muscles, increases vascular permeability, and causes vasodilation *Bioactive lipid-derived mediators (i.e. leukotrienes, PAF, prostaglandins): released slowly, cause recruitment of other inflammatory cells (neutrophils, eosinophils) to promote vascular permeability and edema, bronchoconstriction or rhinitis, induces further release of histamine Type II: Tissue-specific Hypersensitivity Reactions - ANSWERSCharacterized by a specific cell or tissue being the target of an immune response *antibody binding to tissue-specific antigens or antigens that have attached to particular tissues: 1) the cell can be destroyed by antibody (IgG or IgM) and activation of the complement cascade through classical pathway; 2) antibody may cause cell destruction thru phagocytosis by macrophages; 3) antibody and complement may attract neutrophils which will in turn damage the tissue; 4) antibody-dependent cell-mediated cytotoxicity : subpopulation of cytotoxic cells that are not antigen specific, recognize antibody and release toxic substances to destroy target cell; 5) antibody is usually directed against antigenic determinants associated w/ specific cell surface receptors, and the symptoms of the disease are a result of a direct effect of antibody binding alone Type III Immune Complex-Mediated hypersensitivity reaction - ANSWERSImmune complex mediated: antigen-antibody complexes formed in circulation and deposited in vessel walls or extravascular tissues *not organ specific Type IV cell-mediated hypersensitivity reaction - ANSWERSmediated by T lymphocytes and do not involve antibody; occurs thru either cytotoxic T cells or lymphokine-producing Th1 and Th17 cells -Tc Cells attack and destroy cellular targets directly -Th1 and Th17 cells produce cytokines that recruit and activate phagocytic cells, especially macrophages -destruction of the tissue is usually caused by direct killing by toxins from Tc cells or by the release of soluble factors Examples: graft rejection and allergic reactions from contact w/ poison ivy and metals Allergy - ANSWERShypersensitivity response against environmental antigen *most common hypersensitivity reactions *typical type 1 hypersensitivity allergens: pollens, molds, fungi, foods, and animals *typical type IV allergens: plan resins, metals, acetylates, and chemicals in rubber, cosmetics, detergents, and topical abx *type II and III allergens: abx and soluble antigens produced by infectious agents (hep. B) Clinical symptoms of type 1 allergies - ANSWERS*conjunctivitis *rhinitis *asthma *urticaria *vomiting *diarrhea *abdominal pain