Nokea
Avian Influenza has not so far caused a human pandemic because
- A. Avian flu causes only mild infection in humans compared to birds
- B. Avian flu recognizes a variant of sialic acid found only on avian cells
- C. Avian flu recognizes a variant of sialic acid only found deep in the lung tissue of humans, not in the upper airways
- D. H5N1 is included in the composition of the annual trivalent inactivated vaccine
Correct Answer: C
Rationale: The correct answer is C because avian flu recognizing a variant of sialic acid only found deep in the lung tissue of humans, not in the upper airways explains why it has not caused a human pandemic. This specificity limits human-to-human transmission as the virus cannot efficiently attach in the upper airways where respiratory droplets are expelled. Choices A and B are incorrect because avian flu can cause severe infections in humans and recognizes a variant of sialic acid found in both birds and humans, not just avian cells. Choice D is incorrect as the presence of H5N1 in the annual trivalent vaccine does not prevent human pandemic potential.
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The researcher that postulated the existence of 'pattern recognition receptors' on innate cells was:
- A. Susumu Tonegawa
- B. Ilya Metchnikoff
- C. Charles Janeway
- D. Ralph Steinman
Correct Answer: C
Rationale: The correct answer is C: Charles Janeway. He proposed the existence of pattern recognition receptors on innate cells in the 1980s, leading to the development of the concept of innate immunity. Janeway's hypothesis revolutionized our understanding of immune responses by emphasizing the role of pattern recognition in detecting pathogens. Tonegawa is known for his work on immune diversity; Metchnikoff discovered phagocytes; and Steinman identified dendritic cells. Janeway's contribution to immunology specifically focuses on pattern recognition receptors, making him the correct choice for this question.
Normal mice injected with high doses of LPS die of septic shock. Mice resistant to LPS-induced septic shock have a mutation in which receptor?
- A. TLR4
- B. TLR5
- C. NOD1
- D. NOD2
Correct Answer: A
Rationale: Step 1: TLR4 is the receptor for lipopolysaccharide (LPS), a component of gram-negative bacteria.
Step 2: The question states that normal mice injected with high doses of LPS die, indicating TLR4 activation.
Step 3: Mutations in TLR4 can confer resistance to LPS-induced septic shock.
Step 4: Therefore, the correct answer is A: TLR4, as it is directly involved in recognizing LPS and triggering septic shock.
Summary: B: TLR5 does not specifically bind LPS. C: NOD1 and D: NOD2 are involved in intracellular recognition of bacterial components, not LPS.
A pregnant client requires immediate but temporary protection from chickenpox. Which type of immunization would be required?
- A. Naturally acquired active immunization
- B. Artificially acquired active immunization
- C. Passive immunization
- D. Artificially acquired passive immunization
Correct Answer: D
Rationale: Passive immunization provides immediate but temporary protection by introducing pre-formed antibodies which is crucial for a pregnant client who cannot wait for an active immune response.
What is the key immune cell involved in granuloma formation?
- A. Mast cells
- B. Macrophages
- C. Neutrophils
- D. Dendritic cells
Correct Answer: B
Rationale: The correct answer is B: Macrophages. Macrophages are key immune cells involved in granuloma formation. They play a crucial role in engulfing and processing pathogens or foreign particles, leading to the formation of granulomas as part of the body's immune response. Mast cells (A) are primarily involved in allergic reactions. Neutrophils (C) are important in the initial immune response to infections but are not typically associated with granuloma formation. Dendritic cells (D) are important in antigen presentation and activation of T cells, but they are not the primary immune cells involved in granuloma formation.
Cardiac output
- A. coronary insufficient circulation
- B. A defect in one or more heart valves
- C. Disorder in a heartbeat
- D. Amount of blood/minute pumped into systemic circuit
Correct Answer: D
Rationale: The correct answer is D because cardiac output refers to the amount of blood pumped by the heart into the systemic circulation per minute. It is a crucial measure of heart function. Option A, coronary insufficient circulation, specifically refers to inadequate blood flow to the heart muscle itself, not overall cardiac output. Option B, a defect in heart valves, would affect the efficiency of blood flow but not necessarily the total amount of blood pumped. Option C, a disorder in heart rhythm, relates to irregular heartbeat patterns rather than the volume of blood pumped. Therefore, D is the correct choice as it directly relates to the definition of cardiac output.