A patient has come to the ambulatory care clinic with a sprain. The nurse correctly differentiates a grade 2 sprain from a grade 3 sprain with the assessment of which finding?

Correct Answer: D

Rationale: The correct answer is D: Minor loss of function. A grade 2 sprain involves partial tearing of the ligament, leading to moderate pain, swelling, and a significant loss of function. In contrast, a grade 3 sprain involves complete tearing of the ligament, resulting in severe pain, significant swelling, and major loss of function. By assessing for minor loss of function, the nurse can differentiate between the two grades of sprains. Choices A, B, and C are incorrect because they do not specifically differentiate between a grade 2 and grade 3 sprain based on the level of functional impairment.

Correct Answer: A

Rationale: The correct answer is A: IgA. IgA is found in breast milk and plays a crucial role in providing immunity to the infant. It helps protect against infections in the digestive and respiratory tracts. IgM is primarily found in the bloodstream, IgD is mainly on the surface of B cells, and IgG is transferred from the mother to the fetus during pregnancy. IgA is the specific immunoglobulin class present in breast milk, making it the correct choice.

Correct Answer: C

Rationale: The correct answer is C: IL-10. IL-10 is known to polarize activated T cells towards a TH2 subset by suppressing TH1 cytokine production. IL-12 (A) promotes TH1 differentiation, IL-2 (B) supports T cell proliferation, and IL-5 (D) is involved in eosinophil activation and differentiation, not in polarizing T cells towards a TH2 subset.

Correct Answer: C

Rationale: The correct answer is C: Thymic medullary region. AIRE (Autoimmune Regulator) is expressed in the thymic medullary region. This region is crucial for central tolerance by deleting self-reactive T cells to prevent autoimmune reactions. AIRE regulates the expression of tissue-specific antigens in medullary thymic epithelial cells, leading to negative selection of autoreactive T cells. Choices A, B, and D are incorrect as AIRE is not primarily expressed in bone marrow, thymic cortical region, or LN cortex.

Correct Answer: B

Rationale: The correct answer is B: gp41. Gp41 is responsible for the fusion of the viral envelope with the cell plasma membrane by undergoing conformational changes that allow the viral and cellular membranes to merge. Gp120 attaches to the host cell receptor (CD4), facilitating the binding of the virus to the host cell. Gp160 is the precursor protein that is cleaved into gp120 and gp41 during viral maturation. CXCR4 is a cellular co-receptor used by some strains of HIV to enter host cells but is not directly involved in the fusion process.