Capillaries

A portal system contains two capillary beds in series. Blood flows from the heart through the first capillary bed where it then drains into a portal vein. The portal vein carries the blood to a second capillary bed that drains into a vein that returns blood to the heart. The hepatic portal system is one example of a portal system. Its first capillary bed is located in the intestines and the second in the liver.


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