NEET BIOLOGY

Detailed explanation-1: -The absorption of most dietary iron occurs in the duodenum and proximal jejunum and depends heavily on the physical state of the iron atom. At physiological pH, iron exists in the oxidized, ferric (Fe3+) state. To be absorbed, iron must be in the ferrous (Fe2+) state or bound by a protein such as heme.

Detailed explanation-2: -Most iron absorption occurs in the upper part of the intestine, the duodenum and proximal jejunum, across polarized intestinal epithelial cells, or enterocytes [6].

Detailed explanation-3: -Intestinal mucosal cells in the duodenum and upper jejunum absorb the iron. The iron is coupled to transferrin (Tf) in the circulation which delivers it to the cells of the body. Phytates, tannins and antacids block iron absorption.

Detailed explanation-4: -Cells in the section of the small intestine located just after the stomach (duodenum) absorb iron after enzymes change the iron in food from ferric iron (Fe3+) to a more easily absorbed ferrous iron (Fe2+). An acidic environment, where there is low gastric pH, provides the best environment for this process.

Detailed explanation-5: -Dietary iron is processed and absorbed by the mucosal cells of the small intestine. Only about 10% of the iron we consume each day is absorbed into the body, however.