The Liver

Anatomy of the Liver

Anatomy Overview

The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm, and on top of the stomach, right kidney, and intestines. Shaped like a cone pr wedge, the liver is a dark reddish-brown organ that generally weighs about 3 pounds.

There are two distinct sources that supply blood to the liver, including the following:

• Oxygenated blood flows in from the hepatic artery
• Nutrient-rich blood flows in from the hepatic portal vein

The liver holds about one pint (13 percent) of the body's blood supply at any given moment. The liver consists of two main lobes, both of which are made up of thousands of lobules. These lobules are connected to small ducts that connect with larger ducts to form the hepatic duct. The hepatic duct transports bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine).

Macroscopic Structure

Ligaments connect the upper surface of the liver to the diaphragm and the abdominal wall and the under surface to the stomach and duodenum. The gall bladder is located on the under surface of the right lobe of the liver. Neighboring organs include the colon, the intestines, and the right kidney.

Microscopic Structure

Lobules: Hexagonally shaped functional units of the liver, made up of liver cells arranged in one-cell-thick plate-like layers that radiate from the central vein to the edge of the lobule.

Hepatocytes: The liver cells.

Sinusoids: Small blood vessels between the radiating rows of hepatocytes. They receive oxygen-rich blood from the hepatic artery and nutrients from the intestines via the portal vein. Oxygen and nutrients diffuse through the capillary walls into the liver cells.

Bile ducts: Bile is drained from the liver cells by many small ducts that unite to form the main bile duct of the liver, the hepatic duct. This joins the cystic duct, which leads from the gallbladder, to form the common bile duct, which drains into the duodenum.

Central vein: A blood vessel in the middle of each lobule, which receives blood from the hepatic portal vein and hepatic artery via the sinusoids and drains the blood into the hepatic vein.