NUR-631 Final Exam QUESTIONS AND ANSWERS WITH RATIONALES

How are target cells destroyed in a type II hypersensitivity reaction? a. Tissue damage from mast cell degranulation b. Antigen-antibody complexes deposited in vessel walls c. Cytotoxic T lymphocytes attack the cell directly. d. Natural killer cells - ANSWER- ANS: D RATIONALE: The mechanism that results in a type II hypersensitivity reaction involves a subpopulation of cytotoxic cells that are not antigen specific (natural killer [NK] cells). Antibody on the target cell is recognized by Fc receptors on the NK cells, which releases toxic substances that destroy the target cell. Tissue damage from mast cell degranulation occurs in type I hypersensitivity reactions. Antigen-antibody complexes are active in type III hypersensitivity responses. Cytotoxic lymphocytes are involved in type IV hypersensitivity responses. Graves disease (hyperthyroidism) is an example of which type II hypersensitivity reaction? a. Modulation b. Antibody-dependent cell-mediated cytotoxicity c. Neutrophil-mediated damage d. Complement-mediated lysis - ANSWER- ANS: A RATIONALE: The antibody reacts with the receptors on the target cell surface and modulates the function of the receptor by preventing interactions with their normal ligands, replacing the ligand and inappropriately stimulating the receptor or destroying the receptor. For example, in the hyperthyroidism (excessive thyroid activity) of Graves disease, autoantibody binds to and activates receptors for thyroid-stimulating hormone (TSH) (a pituitary hormone that controls the production of the hormone thyroxine by the thyroid). Graves disease is not a result of cell- mediated cytotoxicity, neutrophil-mediated damage, or complement- mediated lysis. Immunoglobulin E (IgE) is associated with which type of hypersensitivity reaction? a. I b. II c. III d. IV - ANSWER- ANS: A RATIONALE: Hypersensitivity reactions have been divided into four distinct types: type I (IgE-mediated) hypersensitivity reactions, type II (tissue-specific) hypersensitivity reactions, type III (immune complex-mediated) hypersensitivity reactions, and type IV (cell-mediated) hypersensitivity reactions. A Rh-negative woman gave birth to a Rh-positive baby. When discussing Rho[D] immunoglobulin with her, what information should the healthcare professional provide? It provides protection against infection from poor immunity in the baby. It prevents alloimmunity and hemolytic anemia of the newborn. It provides necessary antibodies in case the mother doesn't breastfeed. It causes the intestinal tract of the newborn to produce antibodies. - ANSWER- ANS: B RATIONALE: Alloimmunity occurs when an individual's immune system reacts against antigens on the tissues of other members of the same species. This can occur when a woman is Rh-negative and gives birth to an Rh-positive baby, leading to hemolytic anemia of the newborn. Rho[D] immunoglobulin does not provide protection against infection, provide antibodies to a bottle-fed baby, or cause the intestine to produce antibodies.