Nokea
Which of the following is not a consequence of anaphylactic shock?
- A. Constriction of airways
- B. Loss of blood pressure
- C. Hives
- D. Binding of allergen-specific IgE to mast cells
Correct Answer: D
Rationale: The correct answer is D because the binding of allergen-specific IgE to mast cells is actually a key event in anaphylactic shock, leading to the release of inflammatory mediators. Constriction of airways (A), loss of blood pressure (B), and hives (C) are all consequences of anaphylactic shock due to the systemic release of histamine and other mediators. IgE binding to mast cells triggers the release of these mediators, causing the symptoms associated with anaphylaxis. Therefore, D is the correct answer as it is not a consequence but rather an initiating event in anaphylactic shock.
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Which of the following statements concerned with the microbiota is NOT true?
- A. It colonizes our body at birth
- B. Its composition in adults is influenced by several factors, including diet and exercise
- C. Obesity is associated with alterations in the composition of gut microbiota. This condition has been shown to be transmissible in mice when microbiota from obese mice is transferred to lean mice
- D. Bacteria found in obese mice are less efficient at extracting energy from food and this in turn impacts on the sense of satiety of the animal.
Correct Answer: D
Rationale: The correct answer is D because it is the only statement that is not entirely true regarding the microbiota. The rationale for this is that bacteria found in obese mice are actually more efficient at extracting energy from food, not less efficient as mentioned in option D. This increased efficiency contributes to the higher energy extraction from food, leading to weight gain in obese individuals. The other options (A, B, C) are correct as they align with current research and understanding of the microbiota. Option A is true as the microbiota begins to colonize our body at birth. Option B is also true as the composition of the microbiota in adults can indeed be influenced by various factors such as diet and exercise. Option C is true as obesity has been linked to alterations in gut microbiota composition, and studies have shown that transferring microbiota from obese to lean mice can induce weight gain in the lean mice.
What is the role of pattern recognition in innate immunity, as proposed by Janeway?
- A. Specific recognition of antigens
- B. Binding toxins to create immunity
- C. Identifying common pathogen-associated molecular patterns
- D. Suppressing lymphocyte activation
Correct Answer: C
Rationale: Pattern recognition in innate immunity, as proposed by Janeway, involves identifying common pathogen-associated molecular patterns (PAMPs). This is crucial for initiating the immune response against pathogens. PAMPs are specific molecular patterns found on pathogens but not on host cells. By recognizing these patterns, the innate immune system can quickly and effectively identify potential threats and trigger the appropriate immune response.
Explanation of why other choices are incorrect:
A: Specific recognition of antigens is a function of adaptive immunity, not innate immunity.
B: Binding toxins to create immunity is not the primary role of pattern recognition in innate immunity.
D: Suppressing lymphocyte activation is not the role of pattern recognition in innate immunity; rather, it is involved in activating immune responses against pathogens.
Which of the following statements is most correct? Immunoglobulin gene rearrangement:
- A. Occurs after transcription of an immunoglobulin gene
- B. Creates a complete V exon in the germline DNA
- C. Creates a complete V exon in the B cell DNA
- D. Both A and B are correct
Correct Answer: C
Rationale: The correct answer is C because immunoglobulin gene rearrangement creates a complete V exon in the B cell DNA. This process happens during B cell development, where segments of V, D, and J gene regions are rearranged to form a functional immunoglobulin gene. This rearrangement occurs before transcription, so option A is incorrect. Option B is incorrect because the V exon is not complete in the germline DNA, but rather created through rearrangement in the B cell DNA. Option D is incorrect as it combines two incorrect statements.
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.
A patient with a pH of 7.29 has metabolic acidosis. Which value is useful in determining whether the cause of the acidosis is an acid gain or a bicarbonate loss?
- A. PaCO2
- B. Anion gap
- C. Serum Na+ level
- D. Bicarbonate level
Correct Answer: D
Rationale: Bicarbonate levels help differentiate between acid gain (low bicarbonate) and bicarbonate loss (normal or high anion gap).