Vein

Blood Vessels that carry the blood from the periphery to the heart. The body veins lead the oxygen-deficient blood from the periphery to the atrium of the right heart, the pulmonary veins lead the oxygen-enriched blood from the lungs to the left atrium, and the veins of the portal vein circulation from the digestive organs, the spleen and the pancreas to the liver and from there through the liver veins to the right atrium.

https://en.wikipedia.org/wiki/vein

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