Intrinsic factor of castle is present in:
**Core Concept**
The intrinsic factor of Castle is a glycoprotein produced by the parietal cells of the stomach, which plays a crucial role in the absorption of vitamin B12. It forms a complex with vitamin B12, facilitating its binding to receptors in the ileum and subsequent absorption.
**Why the Correct Answer is Right**
The intrinsic factor of Castle is synthesized by the parietal cells of the gastric mucosa and secreted into the gastric juice. It binds to vitamin B12, protecting it from degradation and facilitating its absorption in the terminal ileum. This process is essential for the maintenance of normal hematopoiesis, as vitamin B12 is required for the synthesis of DNA and the production of red blood cells.
**Why Each Wrong Option is Incorrect**
**Option A:** The correct answer is not the stomach lining, as the intrinsic factor is a specific glycoprotein produced by the parietal cells, not a general characteristic of the stomach lining.
**Option B:** The intrinsic factor is not produced by the chief cells, which produce pepsinogen and gastric amylase.
**Option C:** The intrinsic factor is not produced by the gastric mucosa's mucous cells, which produce mucus to protect the stomach lining.
**Clinical Pearl / High-Yield Fact**
The intrinsic factor deficiency leads to vitamin B12 deficiency, which can cause megaloblastic anemia, neurological symptoms, and increased risk of cardiovascular disease.
**Correct Answer:** C. Parietal cells of the gastric mucosa.