Intrinsic factor, which helps in absorption of Vit. B12 is produced by:
**Core Concept**
Intrinsic factor is a glycoprotein produced by the parietal cells in the stomach lining, which plays a crucial role in the absorption of vitamin B12. This protein binds to vitamin B12 in food and facilitates its absorption in the terminal ileum of the small intestine.
**Why the Correct Answer is Right**
Intrinsic factor binds to vitamin B12 in the stomach and protects it from degradation in the acidic environment. This complex is then absorbed in the terminal ileum by specific receptors, enabling the absorption of vitamin B12. The intrinsic factor-vitamin B12 complex is essential for the maintenance of normal hematopoiesis, nervous system function, and DNA synthesis.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the correct answer is not specified, and this option does not provide any relevant information about the production of intrinsic factor.
**Option B:** This is incorrect because while the stomach does produce intrinsic factor, it is not produced by the chief cells, which are responsible for producing pepsinogen.
**Option C:** This is incorrect because the pancreas does produce digestive enzymes, but it is not responsible for producing intrinsic factor.
**Clinical Pearl / High-Yield Fact**
Intrinsic factor deficiency, often seen in pernicious anemia, can lead to severe vitamin B12 deficiency and neurological manifestations, including ataxia, weakness, and cognitive impairment.
**Correct Answer: C. Parietal cells.**