MCQs Iron Metabolism and Anemia
a) Synthesis of hemoglobin
b) Synthesis of vitamin D
c) Regulation of blood pressure
d) Production of thyroid hormones
2. Which of the following is the storage form of iron in the body?
a) Transferrin
b) Ferritin
c) Hemosiderin
d) Hemoglobin
3. Iron absorption is enhanced by the presence of which nutrient?
a) Vitamin C
b) Vitamin B12
c) Vitamin A
d) Vitamin D
4. Anemia of chronic disease is characterized by:
a) Elevated transferrin saturation
b) Increased iron absorption
c) High serum iron levels
d) Low serum ferritin levels
5. Which type of anemia is caused by a deficiency of vitamin B12 or folate?
a) Aplastic anemia
b) Hemolytic anemia
c) Pernicious anemia
d) Iron-deficiency anemia
6. Microcytic, hypochromic anemia is typically seen in:
a) Aplastic anemia
b) Folate deficiency
c) Iron-deficiency anemia
d) Vitamin B12 deficiency
7. Which of the following conditions is characterized by an inherited defect in hemoglobin synthesis, leading to misshapen red blood cells?
a) Aplastic anemia
b) Pernicious anemia
c) Sickle cell anemia
d) Thalassemia
8. The Schilling test is used to diagnose deficiencies of which vitamin?
a) Vitamin A
b) Vitamin B12
c) Vitamin C
d) Vitamin D
9. Which of the following anemias is characterized by a deficiency of intrinsic factor, leading to impaired vitamin B12 absorption?
a) Aplastic anemia
b) Hemolytic anemia
c) Pernicious anemia
d) Thalassemia
10. Which iron-containing molecule is responsible for oxygen transport in red blood cells?
a) Myoglobin
b) Hemoglobin
c) Ferritin
d) Transferrin
11. What is the main function of the hormone erythropoietin (EPO) in relation to iron metabolism?
a) Breaking down excess iron in the spleen
b) Enhancing iron absorption in the intestines
c) Regulating iron storage in the liver
d) Stimulating red blood cell production in the bone marrow
12. Which of the following is a genetic disorder that results in abnormal hemoglobin structure and is most commonly found in individuals of African, Mediterranean, and Southeast Asian descent?
a) Iron-deficiency anemia
b) Pernicious anemia
c) Sickle cell anemia
d) Thalassemia
13. Which dietary component can inhibit iron absorption when consumed in excess, leading to potential iron-deficiency anemia in susceptible individuals?
a) Calcium
b) Vitamin C
c) Vitamin B12
d) Vitamin D
14. Which of the following substances binds to dietary iron in the small intestine and transports it into the bloodstream for utilization?
a) Erythropoietin
b) Ferritin
c) Hemoglobin
d) Transferrin
15. Which of the following laboratory parameters is most indicative of iron-deficiency anemia?
a) Elevated serum ferritin levels
b) Increased transferrin saturation
c) Low mean corpuscular volume (MCV)
d) Elevated hemoglobin levels
16. Anemia resulting from chronic kidney disease is primarily due to a deficiency in which hormone?
a) Calcitonin
b) Erythropoietin (EPO)
c) Insulin
d) Thyroid hormone
17. Which type of anemia is characterized by destruction of red blood cells at a rate that exceeds production, often resulting from autoimmune reactions or hereditary conditions?
a) Aplastic anemia
b) Hemolytic anemia
c) Iron-deficiency anemia
d) Sideroblastic anemia
18. In which organ is the majority of iron recycled from senescent red blood cells and reused for hemoglobin synthesis?
a) Liver
b) Kidneys
c) Lungs
d) Spleen
19. Which of the following is a characteristic feature of anemia associated with chronic inflammation or infection?
a) High serum iron levels
b) Elevated hemoglobin levels
c) Low serum iron levels
d) Increased erythropoietin (EPO) production
20. Which type of anemia is characterized by impaired heme synthesis, leading to the accumulation of iron in the mitochondria of erythroid precursors?
a) Aplastic anemia
b) Hemolytic anemia
c) Iron-deficiency anemia
d) Sideroblastic anemia
Answers with Explanation:
1. a) Synthesis of hemoglobin
Explanation: Iron is an essential mineral that plays a crucial role in the synthesis of hemoglobin, the protein in red blood cells responsible for carrying oxygen from the lungs to the rest of the body.
2. b) Ferritin
Explanation: Ferritin is a protein that serves as the storage form of iron in the body. It helps store excess iron in a non-toxic form until it is needed for various physiological processes.
3. a) Vitamin C
Explanation: Vitamin C enhances iron absorption by reducing dietary iron to a more absorbable form and by promoting the uptake of iron by intestinal cells.
4. d) Low serum ferritin levels
Explanation: Anemia of chronic disease is often associated with inflammation and chronic illnesses. It is characterized by low levels of serum iron, low transferrin saturation, and low serum ferritin levels due to impaired iron utilization for erythropoiesis.
5. c) Pernicious anemia
Explanation: Pernicious anemia is caused by a deficiency of vitamin B12, which can result from a lack of intrinsic factor or other factors that affect vitamin B12 absorption. Folate deficiency can also lead to a similar type of anemia.
6. c) Iron-deficiency anemia
Explanation: Microcytic anemia is characterized by smaller-than-normal red blood cells, and hypochromic anemia indicates a decrease in hemoglobin content within these cells. Iron-deficiency anemia is a common cause of this type of anemia.
7. d) Thalassemia
Explanation: Thalassemia is a group of inherited blood disorders characterized by an abnormality in the production of hemoglobin, resulting in misshapen red blood cells. This can lead to anemia and other complications.
8. b) Vitamin B12
Explanation: The Schilling test is used to diagnose vitamin B12 deficiency, particularly pernicious anemia. It assesses the absorption of radioactive vitamin B12 in the gastrointestinal tract.
9. c) Pernicious anemia
Explanation: Pernicious anemia is caused by a deficiency of intrinsic factor, a protein necessary for the absorption of vitamin B12 in the intestines. Without intrinsic factor, vitamin B12 absorption is impaired, leading to anemia.
10. b) Hemoglobin
Explanation: Hemoglobin is the iron-containing molecule found in red blood cells that binds to oxygen in the lungs and releases it to tissues throughout the body, facilitating oxygen transport.
11. d) Stimulating red blood cell production in the bone marrow
Explanation: Erythropoietin (EPO) is a hormone produced by the kidneys in response to low oxygen levels. Its main function is to stimulate the bone marrow to produce red blood cells, which contain hemoglobin and require iron for oxygen transport.
12. c) Sickle cell anemia
Explanation: Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene, resulting in the production of abnormal hemoglobin. This leads to the characteristic sickle-shaped red blood cells and is most commonly found in individuals of certain ethnic backgrounds.
13. a) Calcium
Explanation: Calcium can interfere with the absorption of non-heme iron when consumed in excess, particularly when taken with iron-rich foods. This can lead to reduced iron absorption and potentially contribute to iron-deficiency anemia.
14. d) Transferrin
Explanation: Transferrin is a protein that binds to iron in the small intestine and transports it through the bloodstream to various cells, including those involved in red blood cell production.
15. c) Low mean corpuscular volume (MCV)
Explanation: Mean corpuscular volume (MCV) is a measure of the average size of red blood cells. In iron-deficiency anemia, red blood cells tend to be smaller (microcytic), leading to a low MCV value.
16. b) Erythropoietin (EPO)
Explanation: Anemia associated with chronic kidney disease is primarily due to a deficiency in erythropoietin (EPO), a hormone that stimulates the bone marrow to produce red blood cells. In kidney disease, EPO production is reduced, leading to decreased red blood cell production.
17. b) Hemolytic anemia
Explanation: Hemolytic anemia is characterized by the premature destruction of red blood cells, leading to a decrease in their lifespan. This can result from autoimmune disorders, genetic mutations, or other factors that accelerate red blood cell breakdown.
18. d) Spleen
Explanation: The spleen is the primary organ responsible for recycling iron from senescent (old) red blood cells. It breaks down hemoglobin and releases iron, which can then be transported back to the bone marrow for the synthesis of new hemoglobin.
19. c) Low serum iron levels
Explanation: Anemia associated with chronic inflammation or infection is characterized by low serum iron levels. Inflammatory cytokines can interfere with iron metabolism, leading to decreased iron availability for erythropoiesis.
20. d) Sideroblastic anemia
Explanation: Sideroblastic anemia is characterized by impaired heme synthesis, which results in the accumulation of iron in the mitochondria of erythroid precursors. This leads to the characteristic ringed sideroblasts seen in bone marrow samples.
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