What is the role of duodenal cytochrome b in the regulation of iron absorption in the small intestine?

A It enhances iron absorption by reducing ferric iron to ferrous iron ✓
B It inhibits iron absorption by oxidizing ferrous iron to ferric iron
C It has no role in iron absorption
D It regulates the expression of iron transport proteins

Explanation

Duodenal cytochrome b is an enzyme that reduces ferric iron to ferrous iron, making it more soluble and available for absorption in the small intestine.

Source

Guyton and Hall Textbook of Medical Physiology
Hematology Hematology: Anemia Hematology: Anemia Hard MEDICAL Confidence: high