Nokea
Which of the following is NOT true about multiple sclerosis (MS)
- A. Sex bias observed with males more at risk of developing the disease
- B. Incidence higher in northern countries
- C. Symptoms caused by demyelination of neurons
- D. EAE is an animal model for MS induced by injection with myelin
Correct Answer: A
Rationale: The correct answer is A: Sex bias observed with males more at risk of developing the disease. This statement is NOT true because MS actually has a sex bias towards females, with women being more at risk. This is due to hormonal, genetic, and immunological factors. The other choices are true: B is correct as MS is more common in northern regions, possibly due to environmental factors; C is correct since MS is characterized by demyelination of neurons leading to various symptoms; and D is correct as experimental autoimmune encephalomyelitis (EAE) is an animal model often used to study MS, induced by injecting myelin components to trigger an immune response.
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Which of the following is NOT an outcome of complement activation:
- A. Increased recruitment of inflammatory cells
- B. Opsonization of pathogens
- C. Lysis of pathogens
- D. Increased migration of dendritic cells from tissues to lymph nodes
Correct Answer: D
Rationale: The correct answer is D: Increased migration of dendritic cells from tissues to lymph nodes. Complement activation does not directly lead to the migration of dendritic cells. Complement activation can lead to increased recruitment of inflammatory cells (A), opsonization of pathogens (B), and lysis of pathogens (C). Dendritic cells typically migrate to lymph nodes to present antigens to T cells, but this process is not directly mediated by complement activation.
Which of the following does not describe defensins?
- A. They disrupt pathogen membranes by penetrating them and disrupting their integrity
- B. They function as opsonins
- C. They are amphipathic, that is they have hydrophobic and hydrophilic regions
- D. They are contained in neutrophil granules
Correct Answer: B
Rationale: The correct answer is B: They function as opsonins.
Rationale:
1. Defensins disrupt pathogen membranes by penetrating them (A), not by functioning as opsonins.
2. Defensins are amphipathic (C), having hydrophobic and hydrophilic regions, which aid in membrane disruption.
3. Defensins are contained in neutrophil granules (D), contributing to their role in the immune response.
Summary:
Choice B is incorrect because defensins do not function as opsonins, which are molecules that enhance phagocytosis of pathogens by immune cells. Choices A, C, and D correctly describe aspects of defensins' mechanism of action and localization.
Which of the following is NOT a feature of adaptive immunity?
- A. Slow response compared to innate immunity
- B. Highly specific recognition of antigens
- C. Memory function
- D. Present at birth
Correct Answer: D
Rationale: The correct answer is D: Present at birth. Adaptive immunity is not present at birth; it develops over time in response to exposure to pathogens. A: Adaptive immunity has a slower response compared to innate immunity as it requires activation and proliferation of specific immune cells. B: Adaptive immunity is highly specific in recognizing antigens through antigen receptors on T and B cells. C: Adaptive immunity has memory function, allowing the immune system to "remember" previous encounters with specific pathogens for a faster and stronger response upon re-exposure.
A patient is taking diuretic drugs that cause sodium loss from the kidney. Which fluid or electrolyte imbalance is most likely to occur in this patient?
- A. Hyperkalemia
- B. Hyponatremia
- C. Hypocalcemia
- D. Hypotonic fluid loss
Correct Answer: B
Rationale: Diuretics promote sodium excretion, leading to hyponatremia as more water follows sodium out of the body.
The adaptive immune response:
- A. Is dependent on the innate immune response for initiation
- B. Involves both humoral and cell-mediated responses
- C. Provides cytokines that influence the response of innate cells, i.e. macrophages
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because the adaptive immune response relies on the initiation by the innate immune response (A), involves both humoral (antibody production) and cell-mediated (T cell activation) responses (B), and produces cytokines that can modulate the activity of innate immune cells like macrophages (C). Therefore, all of the statements are true regarding the adaptive immune response, making option D the correct choice.