Introduction

The liver is the largest gland in the body, weighing about 3-4 pounds and making up about 2-3% of the total body weight. It is an extremely vital organ and is known as the mother of the body because it does what most mothers do – a vastly complex multi-tasking performance – including that of a watchdog, grocer, housekeeper, body-guard, bodybuilder, energy plant supervisor, and sanitation engineer -- to name but a few of over 500 separate functions for which it plays a part.

The liver lies just under the rib cage immediately below the diaphragm in the upper right abdominal cavity. It is an extremely vital organ to the body. When it becomes incapacitated for any number of reasons, the effect is systemic. If 85% of the liver stops functioning, every other organ in the body will begin to deteriorate as well.

The liver has four lobes:

Falciform ligament is the tough connective tissue fold that divides the right and left lobes.

The liver lobule is the basic functional unit of the liver. There are about 100,000 of them in the liver.

Hepatocytes are liver cells. They are arranged in a series of irregular plates like the spokes of a wheel. Liver cells produce about one liter of bile every day. Bile is secreted and released into a network of channels called bile canaliculi, which carry the bile away from the central vein and toward larger bile ducts leading to the common hepatic duct. This eventually ends up in the gallbladder for storage. The gallbladder lies under the right lobe of the liver.

Sinusoids are specialized highly permeable capillaries that form passageways between the plates, emptying into the central vein. The sinusoid lining is made up of the typical endothelial cells as well as a large number of phagocytic cells called Kupffer cells, which engulf pathogens, cellular debris, and damaged blood cells. Blood enters the sinusoids from branches of the hepatic portal vein and hepatic artery and leaves through the central vein of the lobule.

Liver diseases lead to degenerative changes in the tissue that cause constriction of blood flow, causing the tissue to die. Liver disease is often the result of such conditions as fibrosis, cirrhosis, or hepatitis. One or more of these three conditions can exist at the same time.

This page was updated in December 2005.