Gross anatomy divides the liver into four lobes based on surface features. The falciform ligament is visible on the front of the liver. This divides the liver into a left anatomical lobe, and a right anatomical lobe. If the liver flipped over, to look at it from behind (the visceral surface), there are two additional lobes between the right and left. These are the caudate lobe (the more superior), and below this the quadrate lobe.
The bile secreted by the liver is collected in the bile canaliculi (tiny canals), which merge to form bile ducts. These eventually drain into the right and left hepatic ducts, which in turn merge to form the common hepatic duct. Bile can either drain directly into the duodenum via the common bile duct or be temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the duodenum together at the ampulla of Vater. The branchings of the bile ducts resemble those of a tree, and indeed the term "biliary tree" is commonly used in this setting.
The splenic vein joins the inferior mesenteric vein, which then together join the superior mesenteric vein to form the hepatic portal vein, bringing venous blood from the spleen, pancreas, stomach, small intestine, and large intestine, so that the liver can process the nutrients and by-products of food digestion. The hepatic veins of the blood can be from other branches such as the superior mesenteric artery. Approximately 60% to 80% of the blood flow to the liver is from the portal venous system, and one fifth of the blood flow is from the hepatic artery.