portal system

anatomy

Also known as: portal circulation

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Last updated

July 2, 2026

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A portal system is a unique part of the circulatory system where blood travels from one capillary bed to another before returning to the heart. In humans, the primary portal system is the hepatic portal system. This system collects nutrient-rich blood from the stomach, intestines, spleen, and pancreas via the portal vein. This blood then flows through specialized vessels in the liver, where it is processed. After passing through the liver, the blood returns to the general circulation. This arrangement allows the liver to process nutrients and detoxify substances absorbed from the digestive tract before they enter the rest of the body.123

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circulatory system
The blood vessels
Lower vertebrates have two so-called portal systems, areas of the venous system that begin in capillaries in tissues and join to form veins, which divide to produce another capillary network en route to the heart. They are called the hepatic (liver) and renal (kidneys) portal systems. The hepatic system is…
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Lower vertebrates have two so-called portal systems, areas of the venous system that begin in capillaries in tissues and join to form veins, which divide to produce another capillary network en route to the heart. They are called the hepatic (liver) and renal (kidneys) portal systems. The hepatic system is…
Read More