Nokea
How do cytokines typically function in the body?
- A. In an endocrine manner
- B. In an autocrine and paracrine manner
- C. Solely by direct contact with pathogens
- D. By degrading immune cells
Correct Answer: B
Rationale: The correct answer is B because cytokines primarily function in an autocrine and paracrine manner. Autocrine signaling occurs when a cell produces a cytokine that acts on the same cell, while paracrine signaling involves cytokines acting on nearby cells. This allows cytokines to regulate immune responses locally. Option A is incorrect as endocrine signaling involves hormones acting on distant target cells via the bloodstream, which is not the primary function of cytokines. Option C is incorrect because cytokines do not require direct contact with pathogens to function. Option D is incorrect as cytokines do not degrade immune cells but rather regulate immune responses.
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The differentiation of activated Th cells into various effector subsets depends mostly on:
- A. Signal 1 of activation
- B. The influence of polarizing cytokines secreted by dendritic cells
- C. Whether the T cell expresses CD4 or CD8
- D. The duration of signaling induced by TCR binding to peptide-MHC
Correct Answer: B
Rationale: The correct answer is B because polarizing cytokines secreted by dendritic cells play a crucial role in determining the differentiation of activated Th cells into specific effector subsets. These cytokines guide the Th cells towards different functional phenotypes, such as Th1, Th2, Th17, or Treg cells. This process helps tailor the immune response to the specific type of pathogen encountered. Choices A, C, and D are incorrect because while signal 1 of activation, T cell receptor co-receptors, and duration of signaling are important factors in T cell activation and differentiation, they do not have as direct and significant an impact on effector subset differentiation as the influence of polarizing cytokines.
In the late 1890s, 'cellularists' and 'humoralists' were intensively arguing about the key components driving the immune response. What was a crucial finding that led the humoralists to dominate the field in the following 50 years?
- A. The demonstration of the Germ Theory of disease
- B. The discovery that cell-free serum could transfer immunity from an immunized animal to a non-immunized one
- C. The discovery of the tuberculin reaction
- D. The determination of the antibody structure
Correct Answer: B
Rationale: The correct answer is B, the discovery that cell-free serum could transfer immunity. This finding led humoralists to dominate because it supported the idea of circulating antibodies in the serum being responsible for immunity. This concept aligned with the humoralist theory, which focused on the role of antibodies in immune response. The ability of cell-free serum to transfer immunity provided direct evidence for humoralists' beliefs.
Choice A (The demonstration of the Germ Theory of disease) is incorrect because while it was a significant advancement in understanding disease, it did not directly impact the argument between cellularists and humoralists regarding the immune response.
Choice C (The discovery of the tuberculin reaction) is incorrect as it was more relevant to the understanding of the immune response to tuberculosis specifically, rather than the broader debate between cellularists and humoralists.
Choice D (The determination of the antibody structure) is incorrect because while understanding antibody structure is crucial, it did not have as direct an impact on the dominance of
Autoimmune diseases are associated with several susceptibility factors. Environmental factors associated with increased risk of autoimmune disease include:
- A. Infections
- B. Level of exposure to the sun
- C. Imbalance of microbiota composition
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Autoimmune diseases have complex causes, involving genetic predisposition and environmental factors. Infections can trigger autoimmune responses, sunlight exposure can influence immune function, and an imbalance in microbiota composition can lead to dysregulated immune responses. Therefore, all three factors can contribute to an increased risk of autoimmune diseases. Choices A, B, and C individually are all associated with autoimmune diseases, making option D the correct choice.
For which type of malignancy should the nurse expect the use of the intravesical route of regional chemotherapy delivery?
- A. Bladder
- B. Leukemia
- C. Osteogenic sarcoma
- D. Metastasis to the brain
Correct Answer: A
Rationale: Intravesical chemotherapy is used for bladder cancer to deliver drugs directly into the bladder.
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.