Nokea
What is the main limitation of innate immunity compared to adaptive immunity?
- A. It cannot produce cytokines
- B. It lacks memory and specificity
- C. It does not include physical barriers
- D. It cannot activate complement
Correct Answer: B
Rationale: The main limitation of innate immunity compared to adaptive immunity is that innate immunity lacks memory and specificity. This means that innate immune responses do not improve upon repeated exposure to the same pathogen and cannot target specific antigens efficiently. Adaptive immunity, on the other hand, can remember previous encounters with pathogens and mount targeted responses. Choices A, C, and D are incorrect because innate immunity can produce cytokines, includes physical barriers like skin and mucous membranes, and can activate complement as part of its defense mechanisms.
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What is the function of MHC molecules on antigen-presenting cells?
- A. Secreting cytokines
- B. Binding and destroying pathogens
- C. Displaying antigen fragments for T cell recognition
- D. Producing antibodies
Correct Answer: C
Rationale: The correct answer is C, displaying antigen fragments for T cell recognition. MHC molecules bind to antigen fragments and present them on the cell surface for T cells to recognize. This process is crucial for activating the immune response. Choice A is incorrect as MHC molecules do not secrete cytokines. Choice B is incorrect as MHC molecules do not directly destroy pathogens. Choice D is incorrect as MHC molecules do not produce antibodies; that is the function of B cells.
Which antibodies are involved in Type II hypersensitivity?
- A. IgE and IgA
- B. IgG and IgM
- C. IgD and IgG
- D. IgM and IgA
Correct Answer: B
Rationale: The correct answer is B (IgG and IgM) because in Type II hypersensitivity, antibodies target antigens on cell surfaces or tissues. IgG and IgM antibodies are involved in this type of immune response by binding to antigens and triggering cell destruction through complement activation or phagocytosis. IgE and IgA (choice A) are typically associated with Type I and Type III hypersensitivity, respectively. IgD (choice C) is primarily involved in B cell activation, while IgA (choice D) is more commonly associated with mucosal immunity.
When teaching the patient with cancer about chemotherapy, which approach should the nurse take?
- A. Avoid telling the patient about possible side effects of the drugs to prevent anticipatory anxiety
- B. Explain that antiemetics,antidiarrheals and analgesics will be provided as needed to control side effects
- C. Assure the patient that the side effects from chemotherapy are uncomfortable but never life threatening
- D. Inform the patient that chemotherapy-related alopecia is usually permanent but can be managed with lifelong use of wigs
Correct Answer: B
Rationale: Providing information about available supportive therapies helps patients manage side effects effectively.
Cells involved in allergic reactions include
- A. Mast cells
- B. Eosinophils
- C. Basophils
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Mast cells, eosinophils, and basophils are all involved in allergic reactions. Mast cells release histamine, leading to inflammation. Eosinophils are involved in allergic responses and parasitic infections. Basophils release histamine and other inflammatory mediators. Therefore, all three cell types play a crucial role in allergic reactions. Choices A, B, and C alone are incorrect because each cell type individually participates in allergic reactions.
The percentage of developing thymocytes undergoing negative selection in the thymus is close to
- A. 90%
- B. 50%
- C. 25%
- D. 10%
Correct Answer: A
Rationale: The correct answer is A (90%). Negative selection in the thymus eliminates self-reactive T cells. The process ensures self-tolerance. The majority of developing thymocytes are removed during negative selection, making it close to 90%. Choices B, C, and D are incorrect because negative selection eliminates a high percentage of thymocytes, not a lower percentage as indicated in those options.