Nokea
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.
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What role do the B-complex vitamins play in wound healing?
- A. Decrease metabolism
- B. Protect protein from being used for energy
- C. Provide metabolic energy for the inflammatory process
- D. Coenzymes for fat, protein, and carbohydrate metabolism
Correct Answer: C
Rationale: B-complex vitamins support energy production, which fuels the inflammatory and reparative processes during wound healing.
All of the following are true with respect to IgM antibodies EXCEPT which one
- A. they fix complement
- B. they occur on the surface of lymphocytes
- C. they predominate in the primary response to antigen
- D. mediate allergic reactions
Correct Answer: D
Rationale: The correct answer is D. IgM antibodies do not mediate allergic reactions. IgE antibodies are responsible for allergic reactions. IgM antibodies fix complement, occur on the surface of lymphocytes, and predominate in the primary response to antigens. IgM is the first antibody produced in response to an infection, playing a key role in the activation of the complement system. IgM antibodies are mainly found in the blood and lymphatic system, not on the surface of lymphocytes. IgE antibodies are the primary mediators of allergic reactions by triggering the release of histamine and other inflammatory molecules.
If HLA-DR4 is considered a 'risk' allele for disease 'X', this means:
- A. All individuals with the HLA-DR4 allele will get disease X
- B. All individuals with disease X have the HLA-DR4 allele
- C. An individual with the HLA-DR4 allele has an increased chance of developing disease X compared to other individuals
- D. All of the above are true
Correct Answer: C
Rationale: The correct answer is C because having the HLA-DR4 allele increases the likelihood of developing disease X but does not guarantee it. Choice A is incorrect because not all individuals with HLA-DR4 will get disease X. Choice B is incorrect because not all individuals with disease X have the HLA-DR4 allele. Choice D is incorrect because it falsely states that all statements are true, which is not the case.
Which of the following is NOT commonly associated with granulomatous hypersensitivity?
- A. Crohn's disease
- B. Sarcoidosis
- C. Systemic lupus erythematosus (SLE)
- D. Tuberculosis
Correct Answer: C
Rationale: Granulomatous hypersensitivity is characterized by the formation of granulomas in response to persistent antigen exposure. Systemic lupus erythematosus (SLE) is an autoimmune disease involving immune complex deposition and inflammation, not granuloma formation. Crohn's disease, sarcoidosis, and tuberculosis are commonly associated with granulomatous hypersensitivity due to their chronic inflammatory nature and granuloma formation in affected tissues. SLE does not typically present with granulomas, making it the correct answer.
In which of the following locations can IgA be found?
- A. In the intestinal lumen
- B. In the lamina propria
- C. In vesicles of enterocytes
- D. In all of the above
Correct Answer: D
Rationale: IgA can be found in the intestinal lumen, lamina propria, and vesicles of enterocytes. IgA is produced by plasma cells in the lamina propria and transported across the epithelial cells into the intestinal lumen where it provides mucosal immunity. It can also be found in vesicles of enterocytes before secretion. Therefore, the correct answer is D as IgA is present in all of the mentioned locations. Choices A, B, and C are incorrect individually as they only represent specific locations where IgA can be found, not all the locations where IgA is present in the gastrointestinal tract.