|MadSci Network: Anatomy|
A good day to you as well.
There is not a lot, really. The main function of the capillary lining of the small intestine is taking nutrients from the contents of the intestine into the blod stream, either by passive diffussion or by active transport through the cells lining the gut.
Two points, however: 1, the cells lining the gut have a high energy consumption due to the many active transport processes they manage, and due to their high proliferation and turnover rate. So the capillaries in the gut also feed the gut itself, and there is a lot of active cells to feed.
2, the contents of the gut have to be processed to have the same content of solvents as the blood - they must be made "isotonic". Since we don't usually live off isotonic drinks, we often need water to make our food digestible. That water is also taken from the blood.
I hope I can help. With best regards from Germany,
Jens Peter Bork, M.D.
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