Nokea
Which of the following leukocytes is involved in antibody-dependent cell-mediated cytotoxicity?
- A. Natural Killer (NK) cells
- B. Neutrophils
- C. Macrophages
- D. Mast cells
Correct Answer: A
Rationale: The correct answer is A: Natural Killer (NK) cells. NK cells are involved in antibody-dependent cell-mediated cytotoxicity by recognizing target cells coated with antibodies and inducing their death. NK cells play a crucial role in immune surveillance and defense against infected or malignant cells. Neutrophils, macrophages, and mast cells are not directly involved in antibody-dependent cell-mediated cytotoxicity. Neutrophils are primarily responsible for phagocytosis, macrophages are antigen-presenting cells, and mast cells are involved in allergic reactions.
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A patient has come to the ambulatory care clinic with a sprain. The nurse correctly differentiates a grade 2 sprain from a grade 3 sprain with the assessment of which finding?
- A. Pain
- B. Swelling
- C. Bleeding into the joint
- D. Minor loss of function
Correct Answer: D
Rationale: The correct answer is D: Minor loss of function. A grade 2 sprain involves partial tearing of the ligament, leading to moderate pain, swelling, and a significant loss of function. In contrast, a grade 3 sprain involves complete tearing of the ligament, resulting in severe pain, significant swelling, and major loss of function. By assessing for minor loss of function, the nurse can differentiate between the two grades of sprains. Choices A, B, and C are incorrect because they do not specifically differentiate between a grade 2 and grade 3 sprain based on the level of functional impairment.
The discovery of immunoglobulin gene rearrangement helped to explain:
- A. How the number of different immunoglobulins produced by an individual can be far greater than the number of genes in the human genome
- B. How the number of genes in the human genome can be far greater than the number of different immunoglobulins produced by an individual
- C. How thousands of immunoglobulin chains of different sequence may be produced by a single B cell
- D. Both A and C are correct
Correct Answer: A
Rationale: The correct answer is A: How the number of different immunoglobulins produced by an individual can be far greater than the number of genes in the human genome. Immunoglobulin gene rearrangement occurs during B cell development, leading to the generation of a diverse repertoire of antibodies from a limited number of genes. This process allows for the production of a vast array of immunoglobulins through mechanisms like V(D)J recombination. Choice B is incorrect because the gene rearrangement process actually enables a single gene to encode for multiple immunoglobulins. Choice C is partially correct but does not fully capture the significance of gene rearrangement in expanding the diversity of immunoglobulins beyond what the genome would suggest. Choice D is incorrect as it combines a correct statement (A) with an incomplete statement (C).
What is a characteristic feature of Goodpasture's syndrome?
- A. Granuloma formation
- B. Pulmonary hemorrhage and glomerulonephritis
- C. Contact dermatitis
- D. Bronchoconstriction and vasodilation
Correct Answer: B
Rationale: The correct answer is B: Pulmonary hemorrhage and glomerulonephritis. Goodpasture's syndrome is an autoimmune disease characterized by the presence of anti-glomerular basement membrane antibodies, leading to damage in the kidneys (glomerulonephritis) and lungs (pulmonary hemorrhage). Granuloma formation (A), contact dermatitis (C), and bronchoconstriction and vasodilation (D) are not characteristic features of Goodpasture's syndrome. Granulomas are more commonly seen in conditions like sarcoidosis, contact dermatitis is an inflammatory skin condition, and bronchoconstriction and vasodilation are features of allergic reactions or asthma, not typically seen in Goodpasture's syndrome.
What is a characteristic feature of atopy?
- A. Tendency to produce IgE in response to allergens
- B. Excess production of IgA antibodies
- C. Suppressed immune response to allergens
- D. Delayed hypersensitivity reaction
Correct Answer: A
Rationale: Step-by-step rationale:
1. Atopy is a genetic predisposition to produce IgE antibodies in response to allergens.
2. IgE antibodies play a crucial role in allergic reactions.
3. Individuals with atopy have an exaggerated immune response to allergens.
4. Excess production of IgA antibodies (B) and suppressed immune response to allergens (C) are not characteristic features of atopy.
5. Delayed hypersensitivity reactions (D) involve a different immune mechanism compared to the immediate IgE-mediated response in atopy.
The basic structure of an antibody molecule is
- A. One light chain and one heavy chain that are covalently linked and form one antigen binding site
- B. Two identical heavy chains and two identical light chains that are covalently linked and form two antigen binding sites
- C. Two identical heavy chains and two identical light chains covalently linked to form one antigen binding site
- D. Two identical light chains that form the antigen binding site and two identical heavy chains that mediate the effector functions of antibodies
Correct Answer: B
Rationale: Rationale for Answer B:
1. Antibody structure consists of two identical heavy chains and two identical light chains.
2. These chains are covalently linked to form the Y-shaped structure of an antibody.
3. Each chain contributes to the formation of antigen-binding sites.
4. Therefore, two identical heavy chains and two identical light chains form two antigen-binding sites.
Summary of Incorrect Choices:
A: Incorrect because it describes only one antigen-binding site formed by one light chain and one heavy chain.
C: Incorrect because it describes one antigen-binding site formed by two identical heavy chains and two identical light chains.
D: Incorrect because it incorrectly describes the roles of light and heavy chains in antibody structure.