B12 absorption Flashcards
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| 5999227873 | 1 | Parietal cells synthesize intrinsic factor (IF) and hydrochloric acid (HCl) Gastric acid converts pepsinogen to pepsin. Pepsin frees vitamin B 12 from ingested proteins. | 0 | |
| 5999227874 | 2 | Free vitamin B 12 binds to R-binders (haptocorrins) synthesized in salivary glands. Protects vitamin B 12 from acid destruction | 1 | |
| 5999239735 | 3 | Pancreatic enzymes in the duodenum cleave off the R-binders. Vitamin B 12 binds to IF to form a complex. | 2 | |
| 5999239737 | 4 | Vitamin B 12 -IF complex is absorbed in the terminal ileum. | 3 | |
| 5999241582 | 5 | Vitamin B 12 binds to transcobalamin II and enters the plasma. Delivered to metabolically active cells or stored in the liver (6- to 9-year supply) | 4 | |
| 5999482203 | What is the role of parietal cells in B12 absorption? | The parietal cells produce intrinsic factor (IF), which is required for B12 absorption in the terminal ileum. A lack of parietal cells results in a lack of intrinsic factor and, therefore, a B12 deficiency | 5 |