What is Portal and Rental Circulation ?
The body has other circulation systems that do not return blood directly to the heart. For instance, the blood that drains from the abdominal systems feeds into the portal circulation system, which moves blood through two separate capillary beds without returning it to the heart.
The hepatic portal system carries nutrient-rich blood from the intestines through the portal vein to the liver. There, blood enters spaces called sinusoids, where it is processed by liver cells. The blood is then collected again into the hepatic vein, which joins the inferior vena cava and from there empties into the right auricle.
The hepatic portal circulation also includes a hepatic artery, which is a branch of the aorta that provides oxygenated blood for the liver. After all, the liver needs oxygen and nutrients too! Along with a multitude of other functions, the liver acts as a storage organ for blood and contains up to a third of all the blood in the body.
Renal circulation, or kidney circulation, consists of two renal arteries that branch off of the aorta, one to each kidney. The kidneys filter nitrogenous wastes from the blood, which flows from the renal capillaries to venues, and from there to the renal veins that empty into the inferior vena cava.