I'm thinking that in more distal parts of the colon, such as sigmoid colon, portal irrigation is not as present as in upper segments. Any ideas on that? Papers containing anatomical references for portal circulation would be helpful.
Hi Ms. Jungles.
Thank you for the great question. This may not be the answer you were looking for, but bile toxins are present in significant quantities from the proximal duodenum all the way through the rectum, which naturally includes the entire colon. Feces is one of 3 primary routes of toxin excretion from the body. The purpose of portal circulation is to ensure these toxins eliminated in bile do not make it into to the rest of the body’s circulatory system. All blood from the absorptive membranes of the intestinal tract is routed through the liver for removal of concentrated toxins before it is routed back into general circulation. Portal circulation is a first line of defense for the body along with 60% of the body’s immune system residing in the gut. Hope this helps. Best wishes for your success.
Yes it is. This is via rectal venous plexuses (external - internal - perimuscular) with their communications, to superior rectal vein - inferior mesenteric vein - splenic vein - portal vein.
Excellent point. The venous plexuses and their anastomoses referred to by Mr. Drizis allow for rectal administration of certain medications that would normally be given orally, bypassing first-pass (hepatic) metabolism (which can be dangerous). There are connections to the portal system in the rectum, but the portal system can be partially bypassed in this way, and only in the most distal portions. So the answer to your question is still “Yes,“ as Mr. Drizis confirms. Thank you again.
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