Q-1. Iron is actively absorbed in: (AIIMS May 07)
a) Stomach
b) Duodenum and proximal jejunum
c) Large intestine
d) Ileum
Answer: Duodenum and proximal jejunum
Explanation:
All most all iron absorption occurs in duodenum. Most of the iron in the diet is in the ferric form, whereas it is ferrous form that is absorbed.
Transport of Fe2+ into Enterocytes occurs via di-valent metal transporter I (DMT-I).
Various dietary factors affect the availability of iron for absorption; for example, the phytic acid found in cereals react with iron to form insoluble compounds in intestine as do phosphates and oxalates.
Gastric secretions dissolve the iron and permit it to form soluble complex with ascorbic acid and other substances that aid its reduction to the ferrous form.