Nokea
Which of the following is a characteristic of the constant region of a T cell receptor?
- A. Mediates antigen binding
- B. Anchors the receptor in the T cell membrane
- C. Interacts with MHC molecules
- D. Structurally diverse amongst all T cell receptors
Correct Answer: B
Rationale: The correct answer is B: Anchors the receptor in the T cell membrane. The constant region of a T cell receptor is responsible for anchoring the receptor in the T cell membrane, providing stability and structural support. This region does not mediate antigen binding (choice A), as that function is carried out by the variable region. It also does not directly interact with MHC molecules (choice C), which is primarily the role of the variable region. Lastly, the constant region is not structurally diverse amongst T cell receptors (choice D), as it remains relatively consistent within a specific T cell subtype.
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During an acute inflammatory response which of the following is the first event
- A. Extravasation of neutrophils
- B. Upregulation of endothelial adhesion molecules
- C. Secretion of opsonins
- D. Phagocytosis
Correct Answer: B
Rationale: The correct answer is B because upregulation of endothelial adhesion molecules is the first event during an acute inflammatory response. This event facilitates the initial recruitment of leukocytes, including neutrophils, to the site of inflammation. Extravasation of neutrophils (choice A) occurs after adhesion molecules are upregulated. Secretion of opsonins (choice C) and phagocytosis (choice D) occur later in the inflammatory response process after the neutrophils have been recruited to the site of inflammation.
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.
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.
What is the role of perforin released by NK cells?
- A. Activating B cells
- B. Forming pores in target cell membranes
- C. Engulfing pathogens
- D. Inducing inflammation
Correct Answer: B
Rationale: Perforin released by NK cells forms pores in target cell membranes, allowing for the entry of granzymes which induce target cell death. This process is crucial for the immune response against infected or abnormal cells. Activating B cells (A) is not the role of perforin, as B cells are primarily activated by antigens. Engulfing pathogens (C) is the role of phagocytes like macrophages, not perforin. Inducing inflammation (D) is not directly related to the function of perforin in forming pores in target cell membranes.
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.