Which of the following best characterizes the function of ferroportin in iron metabolism?

Correct Answer: D

Rationale: The correct answer is D: Transmembrane iron exporter. Ferroportin is a transmembrane protein that functions as an iron exporter, allowing iron to move out of cells. This is crucial in iron metabolism as it facilitates the release of iron from cells into the bloodstream for transport to other tissues. A: A form of storage iron in intestinal mucosal cells - This is incorrect as ferroportin is not involved in storing iron in cells. B: A transport protein in the plasma - This is incorrect as ferroportin is not primarily a plasma protein but rather a transmembrane protein. C: A receptor protein on the surface of erythroid progenitors - This is incorrect as ferroportin is not a receptor protein but an exporter protein.

Correct Answer: B

Rationale: The correct answer is B: Ensure that valid consent is in the medical record. This is the priority because obtaining informed consent is a legal and ethical requirement before any invasive procedure like a bone marrow aspiration and biopsy. Without valid consent, the procedure cannot proceed. Administering pain medication (A) can be important, but ensuring consent comes first. Having the client shower (C) is not a priority before the procedure. Premedicating with sedatives (D) may not be necessary for every client and should be based on individual assessment.

Correct Answer: C

Rationale: The correct answer is C: 'You have lower levels of plasma proteins in the blood.' As we age, there is a decline in the production of plasma proteins, which play a crucial role in immune function. These proteins help fight infections and regulate immune responses. Lower levels can weaken the immune system's ability to respond effectively to pathogens. Choice A is incorrect because while bone marrow does produce blood cells, it does not directly relate to the weakening of the immune system with age. Choice B is incorrect as decreased platelet levels primarily affect blood clotting, not immune function. Choice D is incorrect because lymphocytes becoming more reactive to antigens is not a characteristic of aging immune systems.

Correct Answer: D

Rationale: The correct answer is D: B lymphocyte. IL-2 and IL-4 are essential for the differentiation of B lymphocytes from unilineage progenitor cells into mature circulating cells. IL-2 is crucial for B cell proliferation and survival, while IL-4 is required for B cell activation and class switching. Neutrophils do not require IL-2 and IL-4 for differentiation. Eosinophils are primarily influenced by IL-5. Basophils are influenced by IL-3 and IL-5. Therefore, B lymphocytes are the only cell type among the choices that specifically requires IL-2 and IL-4 for their maturation.

Correct Answer: C

Rationale: The correct answer is C: Rhodnius prolixus. This parasite is responsible for causing Chagas disease. The initial symptoms of unilateral palpebral edema and ipsilateral lymphadenopathy are characteristic of the acute phase of Chagas disease. The development of megaesophagus and megacolon are complications seen in the chronic phase. Rhodnius prolixus is a vector for Trypanosoma cruzi, the parasite that causes Chagas disease. Glossina morsitans is the vector for African trypanosomiasis (sleeping sickness), Ixodes scapularis is the vector for Lyme disease, and Simulium damnosum is the vector for onchocerciasis (river blindness), making them incorrect choices for this particular parasitic infection.