What is function of Intrinsic Factor – (NEET/DNB
**Core Concept**
Intrinsic Factor (IF) is a glycoprotein secreted by the parietal cells of the stomach, playing a crucial role in vitamin B12 absorption. It binds to vitamin B12, forming a complex that is then absorbed by the ileum in the small intestine.
**Why the Correct Answer is Right**
The intrinsic factor-vitamin B12 complex is essential for the absorption of vitamin B12, a critical nutrient required for the synthesis of DNA, fatty acid, and amino acid metabolism. The parietal cells secrete IF in response to histamine stimulation, which binds to the vitamin B12 in the stomach lumen. This complex is then taken up by the ileal mucosa, where the vitamin B12 is released and absorbed into the bloodstream. The absence of IF, as seen in pernicious anemia, leads to vitamin B12 deficiency.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might suggest that IF is involved in the absorption of other nutrients, but its primary function is specific to vitamin B12.
**Option B:** This option might imply that IF is produced by the pancreas, but it is actually secreted by the parietal cells of the stomach.
**Option C:** This option might suggest that IF is involved in the breakdown of proteins, but it plays a crucial role in the absorption of vitamin B12.
**Clinical Pearl / High-Yield Fact**
The absence of intrinsic factor, as seen in pernicious anemia, can lead to severe vitamin B12 deficiency, which can cause neurological symptoms such as numbness, weakness, and ataxia.
**Correct Answer:** A. It binds to vitamin B12 in the stomach lumen and is essential for its absorption in the ileum.