In Depth: Gallbladder and Hepatic Portal System
The gallbladder is a small, sac-like muscle that stores bile from the liver. It is located behind the liver.
The liver produces bile continuously, but the body only needs it a few times a day. The excess sits in the hepatic and cystic ducts, which are connected to the gallbladder. When signaled, the gallbladder contracts and squeezes bile through the cystic duct and into the common bile duct.
The most common ailment that affects the gallbladder is the formation gallstones, or cholelithiasis. These stones are often made up of substances found in bile, namely cholesterol. They can become lodged in the bile ducts and can cause extreme pain.
The Hepatic Portal System
The hepatic portal system is a series of veins that carry blood from the capillaries of the stomach, intestine, spleen, and pancreas to capillaries in the liver. It is part of the body’s filtration system. Its main function is to deliver de-oxygenated blood to the liver to be detoxified further before it returns to the heart.
The hepatic portal system consists of:
- Hepatic portal vein: This is the main vein connected to the liver. It forms at the connection of the inferior and superior mesenteric veins.
- Inferior mesenteric vein: This vein takes blood from the colon and rectum and connects with the portal vein.
- Superior mesenteric vein: This drains blood from the small intestine and connects with the hepatic portal vein.
- Gastrosplenic vein: This tributary is formed by the union of the splenic vein from the spleen and the gastric vein from the stomach. It joins with the mesenteric vein inside the pancreas.
The hepatic portal system is designed to rid the body of toxins, and it cannot detect those that are designed to help it. Some drugs must be taken under the tongue, through the skin, or via suppository to avoid entering the hepatic portal system and being prematurely metabolized in the liver before reaching general circulation.