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Questions and Answers
What effect does hypoxia have on hepcidin synthesis?
What effect does hypoxia have on hepcidin synthesis?
Increased erythropoiesis leads to an increase in hepcidin synthesis.
Increased erythropoiesis leads to an increase in hepcidin synthesis.
False
What laboratory finding is indicated by low ferritin levels?
What laboratory finding is indicated by low ferritin levels?
Iron deficiency
Iron is primarily transported in the bloodstream by ______.
Iron is primarily transported in the bloodstream by ______.
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Match the following types of anemia with their causes:
Match the following types of anemia with their causes:
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Which of the following mechanisms is responsible for iron absorption in the duodenum?
Which of the following mechanisms is responsible for iron absorption in the duodenum?
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Transferrin is a protein that stores iron in the liver and spleen.
Transferrin is a protein that stores iron in the liver and spleen.
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Name one of the primary causes of iron deficiency anemia.
Name one of the primary causes of iron deficiency anemia.
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Iron is primarily stored in the body as __________.
Iron is primarily stored in the body as __________.
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Match the following terms related to iron regulation with their functions:
Match the following terms related to iron regulation with their functions:
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What is the effect of binding of IRP to the Iron Response Element (IRE) when iron levels are low?
What is the effect of binding of IRP to the Iron Response Element (IRE) when iron levels are low?
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In iron overload, IRP/IRE binding is increased.
In iron overload, IRP/IRE binding is increased.
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What is the role of hepcidin in iron metabolism?
What is the role of hepcidin in iron metabolism?
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Hepcidin is produced in the ______.
Hepcidin is produced in the ______.
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Match the following regulatory elements with their functions:
Match the following regulatory elements with their functions:
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What happens to TfR2 levels when iron levels are elevated?
What happens to TfR2 levels when iron levels are elevated?
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Haemochromatosis is related to a deficiency in iron absorption.
Haemochromatosis is related to a deficiency in iron absorption.
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How does increased hepcidin affect iron absorption in the small intestine?
How does increased hepcidin affect iron absorption in the small intestine?
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Study Notes
Iron Deficiency Anemia
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Symptoms of Low Hemoglobin (Hb):
- Tiredness
- Breathlessness
- Pallor
- Cardiovascular symptoms
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4 Main Causes of Iron Deficiency Anemia (IDA):
- Blood loss
- Inadequate iron intake
- Malabsorption
- Increased iron demand
Iron Regulation Cycle
- Dietary iron is absorbed by microvilli in the small intestine (duodenum).
- Iron enters the bloodstream and is transported by transferrin (protein) to bone marrow or the liver.
- Iron is used in bone marrow for red blood cell (RBC) production.
- Iron is stored in the liver as ferritin.
Dietary Iron Absorption and Regulation
- Dietary iron intake is approximately 10-15 mg/day, with only about 1 mg absorbed.
- Iron from meat is absorbed via haem receptors.
- Non-haeme iron is reduced to Fe2+ by ferrireductase, then absorbed via DMT-1.
- Absorbed iron is either stored as ferritin or enters the bloodstream via ferroportin.
- Transferrin transports iron to bone marrow or other tissues
Iron Storage
- Iron is stored as ferritin or haemosiderin.
- Ferritin contains an iron-hydroxide-phosphate compound.
Iron Regulation
-
Iron levels are controlled by four key stages:
- Iron import from the intestine to the enterocyte via DMT-1
- Iron export from the enterocyte into the circulation via ferroportin
- Ferritin synthesis
- TfR-1 (transferrin receptor 1) synthesis
-
Gene Regulation:
- Iron status controls ferritin, TfR1, and DMT-1 genes.
- High iron levels increase ferritin production, and decrease TfR1 and DMT-1.
- Low iron levels decrease ferritin production, and increase TfR1 and DMT-1
-
Hormone Regulation (Hepcidin):
- A polypeptide hormone produced in the liver.
- Its production is controlled by iron levels, inflammation, cytokines, erythropoiesis, and hypoxia.
- Increased hepcidin leads to reduced iron absorption in the small intestine and reduced release of iron from macrophages.
Laboratory Findings
- FBC: Low hemoglobin (Hb), low mean corpuscular volume (MCV), low mean corpuscular hemoglobin (MCH).
- Blood film: Microcytic/hypochromic anemia
- Red Cell Distribution Width (RDW): Measures variation in red blood cell size (higher value = greater variation)
- Ferritin: Low levels
- Zinc Protoporphyrin (ZPP): Elevated levels
- Serum iron: (Not very useful)
- Total Iron Binding Capacity (TIBC): Low transferrin saturation
Differential Diagnosis of Microcytic/Hypochromic Anemia
- Thalassemias: Genetic mutations affecting hemoglobin production
- Anemia of chronic disease:
- Sideroblastic anemia: Deficiency of aminolevulinic acid enzyme causing iron accumulation in mitochondria of red blood cells.
Additional Notes
- Iron accounts for 20% of its body weight.
- Old red blood cells are broken down by macrophages, releasing iron from hemoglobin, which the body transports to bone marrow for reuse.
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Description
Explore the key aspects of iron deficiency anemia, including its symptoms, causes, and the regulation of dietary iron absorption. This quiz covers how iron is utilized and stored in the body and the processes involved in the formation of red blood cells. Test your knowledge about this crucial health topic.
