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The terminal ileum is part of the digestive system. The most distant portion of the small intestine, it aids in digestion by absorbing materials not previously digested by the jejunum, the middle portion of the small intestine. There are several medical conditions, such as Crohn's disease and certain types of cancer, that can have negative effects on it.
The first two portions of the small intestine are called the duodenum and the jejunum. This last portion of the intestine leads to a pouch known as the cecum, which connects the small intestine to the large intestine. A valve known as the ileocecal valve, or ICV, separates the terminal ileum from the cecum.
Materials that are not absorbed by the body by the time they leave the jejunum are precessed by the terminal ileum. This part of the small intestine is also responsible for the absorption of vitamin B-12. Bile salts produced by the liver are absorbed there as well.
There is actually nothing in the small intestine that would serve to separate the middle and last part of the small intestine. There are a few structural differences that allow a skilled professional to tell where one stops and the other begins, however. For instance, the jejunum is slightly darker in color, while there is a bit more fatty tissue located in the terminal ileum.
Crohn's disease is one of a number of medical conditions that produces problems in this area of the digestive system. This is an inflammatory bowel disease that currently has no cure. Treatment is aimed at reducing as many of the symptoms as possible, including nausea, weight loss, and diarrhea. Since Crohn's disease primarily affects this part of the intestine, vitamin B-12 absorption is often compromised and needs to be treated as well.
Lymphoma is a form of cancer affecting the lymphatic glands of the immune system. While this disease has many symptoms, those related to the terminal ileum include loss of appetite and significant weight loss. Chemotherapy or radiation treatments are sometimes necessary to combat aggressive forms of this disease. If tumors develop inside the small intestine, surgery to remove the tumor and repair any other damage may become necessary. Prognosis for this type of cancer is generally better than that involving other types, depending on the patient's overall health and response to treatment.
@deany17 - I'm not a vegan myself, but I've discussed this with a friend of mine who is. (Many vegetarians eat eggs and/or dairy, and so could get B12 from that, whereas vegans don't consume any animal products.)
To be honest, I don't know how B12 reaches the parts of the body it needs from an injection. What I do know is that most vegans have no need of B12 injections. They get their B12 from nutritional yeast (yum), fortified breakfast cereals, fortified milk alternatives like soy milk, and vitamin tablets. There are plenty of ways to get B12 without eating animal products and without having shots.
I've heard that vegetarians often have inadequate intake of vitamin B12 because it is found in meat and animal protein foods, and that come get intramuscular injections of B12 are given to restore normal levels. But since it is an intramuscular injection, how is the B12 absorbed if it doesn't pass through the ileum? Does it just bypass the ileum and go to the liver for storage or does it enter the circulation, without the need for intrinsic factor, and reach the tissues that make blood cells?
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