Nokea
Which of the following statements concerned with multiple sclerosis (MS) is correct?
- A. Genetic factors seem to play a role in predisposition to develop MS
- B. Predisposition to develop MS does not seem to have an environmental component
- C. MS is more common in Central and South America than in North America
- D. The disease seems to be mediated primarily by autoantibodies
Correct Answer: A
Rationale: Rationale: Option A is correct because genetic factors have been identified as playing a role in predisposition to develop MS. Studies have shown a higher risk among individuals with family history. Option B is incorrect because environmental factors, such as vitamin D levels and viral infections, are known to influence MS development. Option C is incorrect as MS is more prevalent in North America and Europe. Option D is incorrect because MS is primarily mediated by T-cell responses, not autoantibodies.
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Which cell type bridges innate and adaptive immunity?
- A. NK cells
- B. Dendritic cells
- C. Plasma cells
- D. Mast cells
Correct Answer: B
Rationale: The correct answer is B: Dendritic cells. Dendritic cells bridge innate and adaptive immunity by capturing antigens, processing them, and presenting them to T cells to initiate adaptive immune responses. NK cells (A) are part of innate immunity, while plasma cells (C) produce antibodies in adaptive immunity. Mast cells (D) are involved in allergic responses, not bridging innate and adaptive immunity.
Which of the following are not found in Cyanobacteria?
- A. thylakoids
- B. gas vesicles
- C. chloroplasts
- D. heterocysts
Correct Answer: C
Rationale: The correct answer is C: chloroplasts. Cyanobacteria do not have chloroplasts because they are prokaryotic organisms and do not possess membrane-bound organelles like chloroplasts found in eukaryotic cells. Instead, they perform photosynthesis using thylakoids, which are membrane-bound compartments where photosynthesis occurs. Gas vesicles are also present in cyanobacteria and help regulate their buoyancy. Heterocysts are specialized cells that aid in nitrogen fixation, a process that allows cyanobacteria to convert atmospheric nitrogen into a form that can be used by the organism. Therefore, the absence of chloroplasts in cyanobacteria makes choice C the correct answer.
What is the medical term for the breakdown of red blood cells?
- A. Leukocytosis
- B. Thrombocytosis
- C. Hemolysis
- D. Anemia
Correct Answer: C
Rationale: The correct answer is C: Hemolysis. Hemolysis is the medical term for the breakdown of red blood cells. This process releases hemoglobin and other components into the bloodstream. Leukocytosis (A) is an increase in white blood cells, thrombocytosis (B) is an increase in platelets, and anemia (D) is a decrease in red blood cells or hemoglobin levels. In this context, hemolysis specifically refers to the breakdown of red blood cells, making it the correct answer.
The nurse provides care to older adults. What should the nurse recognize as being more likely to occur in an older adult than in a younger adult?
- A. High fevers
- B. Fewer infections
- C. More autoimmune disorders
- D. Greater antibody production
Correct Answer: C
Rationale: The correct answer is C: More autoimmune disorders. As individuals age, the immune system weakens, leading to an increased risk of autoimmune disorders where the immune system mistakenly attacks healthy cells. This is more likely in older adults compared to younger adults. High fevers (choice A) are not more likely in older adults, as fever response tends to decrease with age. Fewer infections (choice B) are also less likely in older adults due to a weakened immune response. Greater antibody production (choice D) is not a characteristic of aging, as antibody production may decline with age.
What is the main function of the Membrane Attack Complex (MAC)?
- A. Recruitment of neutrophils
- B. Phagocytosis activation
- C. Lysis of pathogens
- D. Enhancing cytokine production
Correct Answer: C
Rationale: The main function of the Membrane Attack Complex (MAC) is to lyse pathogens by creating pores in their cell membranes. First, MAC assembles on the pathogen's surface. Then, it forms a pore, disrupting the pathogen's membrane integrity, leading to cell lysis. This mechanism is crucial for the immune system to effectively eliminate pathogens.
Choice A (Recruitment of neutrophils) is incorrect because MAC is not involved in recruiting neutrophils. Neutrophil recruitment is typically mediated by other signaling molecules.
Choice B (Phagocytosis activation) is incorrect as MAC does not directly activate phagocytosis. Phagocytosis is a separate process involving the engulfment of pathogens by immune cells.
Choice D (Enhancing cytokine production) is incorrect because MAC does not directly enhance cytokine production. Cytokine production is mainly regulated by other immune cells and signaling pathways.