Final answer:
Intrinsic Factor (IF) is secreted by the gastric glands and is essential for the absorption of vitamin B12 in the small intestine. It binds to B12 and facilitates its uptake in the terminal ileum through endocytosis. Without intrinsic factor, B12 absorption would be impaired, leading to deficiencies that can affect red blood cell production and neurological functioning.
Step-by-step explanation:
Intrinsic Factor (IF) plays a crucial role in the absorption of vitamin B12 in the small intestine. It is secreted by the gastric glands and binds to vitamin B12, preventing its digestion. The complex formed between intrinsic factor and B12 is then taken up by mucosal receptors in the terminal ileum through endocytosis.
This process is essential because vitamin B12 is a very large molecule and cannot be absorbed by simple diffusion like most other water-soluble vitamins. Without intrinsic factor, vitamin B12 absorption would be impaired, leading to deficiencies that can affect red blood cell production and neurological functioning.
An example of the importance of intrinsic factor can be seen in individuals who undergo total gastrectomy (stomach removal) due to stomach cancer. They rely on vitamin B12 injections to prevent deficiency symptoms.