Oral iron supplements are given for iron deficiency anemia. Which of the statement is true regarding the absorption of oral iron supplements?

Correct Answer: A

Rationale: The correct answer is A because iron absorption primarily occurs in the duodenum and upper jejunum of the small intestine. This is where iron is absorbed into the bloodstream and utilized by the body. Absorption in the large intestine, as stated in choice A, is incorrect. Intrinsic factor, mentioned in choice B, is necessary for the absorption of vitamin B12, not iron. Ascorbic acid actually enhances iron absorption, so choice C is incorrect. Absorption in hereditary hemochromatosis, as in choice D, is increased due to a genetic mutation causing excessive iron absorption, not with oral iron supplements.

Correct Answer: D

Rationale: The correct answer is D because heparin binds to antithrombin III, enhancing its ability to inactivate thrombin. This prevents the conversion of fibrinogen to fibrin, thereby inhibiting blood clot formation. Choice A is incorrect because vitamin K-dependent clotting factors are not directly affected by heparin. Choice B is incorrect because heparin does not prevent the activation of platelets, rather it affects the coagulation cascade. Choice C is incorrect as heparin does not directly prevent platelet aggregation, which is more related to antiplatelet agents like aspirin.

Correct Answer: D

Rationale: The correct answer is D because the Philadelphia chromosome is found in myeloid (not lymphoid) cells in Chronic Myeloid Leukemia (CML). This is due to a reciprocal translocation between chromosomes 9 and 22, resulting in a shortened chromosome 22q, not chromosome 22 itself. Choice A is incorrect because the long arm of chromosome 22 is affected. Choice B is incorrect as Philadelphia chromosome-negative cases can have a favorable prognosis. Choice C is incorrect as the presence of the Philadelphia chromosome is diagnostic of CML.

Correct Answer: C

Rationale: The correct answer is C: pernicious anemia. Pernicious anemia is a macrocytic anemia caused by vitamin B12 deficiency, leading to large red blood cells. Sideroblastic anemia (A) is a type of microcytic anemia due to ineffective iron utilization. Thalassemia (B) causes microcytic anemia due to decreased production of hemoglobin. Lead poisoning (D) can also lead to microcytic anemia by disrupting heme synthesis. Therefore, pernicious anemia is the only choice that does not produce microcytic anemia.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Hypersplenism is characterized by splenomegaly (A), causing sequestration and destruction of blood cells. 2. Pancytopenia (B) results from excessive destruction of blood cells in the enlarged spleen. 3. Hypercellular bone marrow (C) is not directly associated with hypersplenism; it is a compensatory response to increased blood cell destruction. 4. Splenectomy (D) can reverse the effects of hypersplenism by removing the source of blood cell destruction. Therefore, the correct answer is C as hypercellular bone marrow is a secondary response to hypersplenism, not a direct association.