The liver is connected to two large blood vessels, the hepatic artery and the portal vein. The hepatic artery carries blood from the aorta to the liver, whereas the portal vein carries blood containing the digested nutrients from the entire gastrointestinal tract, and also from the spleen and pancreas to the liver.
The hepatic veins carry oxygen-depleted blood from the liver to the inferior vena cava. They also transport blood that has been drained from the colon, pancreas, small intestine, and the stomach, and cleaned by the liver. These veins originate from the core vein of the liver lobule, but they do not have any valves. The hepatic duck: A duct that carries bile from the liver into the common bile duct which conveys it to the duodenum (the upper part of the small intestine).
If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.
