Ad
related to: renal portal system
Search results
Results From The WOW.Com Content Network
A renal portal system is a portal venous system found in reptiles, and fish excluding hagfish and lampreys. It is not found in mammals . [ 1 ] Its function is to supply blood to renal tubules when glomerular filtration is absent or downregulated.
The human hepatic portal system delivers about three-fourths of the blood going to the liver.The final common pathway for transport of venous blood from spleen, pancreas, gallbladder and the abdominal portion of the gastrointestinal tract [2] (with the exception of the inferior part of the anal canal and sigmoid colon) is through the hepatic portal vein.
The renal circulation supplies the blood to the kidneys via the renal arteries, left and right, which branch directly from the abdominal aorta. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output .
The renal portal system is absent in mammals, [111] with the exception of monotremes. [112] Mammals are the only class of vertebrates (with exception of some species) that does not have a renal portal system. [113]
In addition to the renal artery blood supply, reptiles also have a renal portal system, which can redirect blood to the kidneys during periods of water deprivation, bypassing the glomeruli, to prevent ischemic necrosis of tubular cells. [21] [57]
The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of the hepatic portal system, one of three portal venous systems in the human body; the others being the hypophyseal and renal portal systems.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Portal hypertension is a condition in which the blood pressure of the portal venous system is too high. It is often the result of cirrhosis of the liver. Liver cirrhosis can lead to increased intrahepatic vascular resistance and vasodilation of portal system arteries, both of which increase pressure in the portal vein. [ 4 ]