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How the Liver Works

Anatomy of the liver

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. The liver is a dark, reddish-brown triangle-shaped organ that weighs about 3 pounds. The liver has many functions.

Image of the liver, gallbladder, and position of the hepatic vein and artery, and common bile duct.

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

  • Oxygenated blood flows into the liver through the hepatic artery.

  • Nutrient-rich blood flows into the liver from the intestines through 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 eight segments that consist of a thousand lobules. These lobules are connected to small ducts that connect with larger ducts from the common hepatic duct. The common hepatic duct transports the bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine) via the common bile duct.

Functions of the liver

The liver regulates most chemical levels in the blood and excretes a product called bile, which helps carry away waste product from the liver. All of the blood leaving the stomach and intestines passes through the liver. The liver processes this blood and breaks down, balances, and creates the nutrients. It also breaks down drugs into forms that are easier to use for the rest of the body. More than 500 vital functions have been identified with the liver. Some of the more well-known functions include the following:

  • Production of bile, which helps carry away waste and break down fats in the small intestine during digestion

  • Production of certain proteins for blood plasma

  • Production of cholesterol and special proteins to help carry fats through the body

  • Conversion of excess glucose into glycogen for storage. (This glycogen can later be converted back to glucose for energy.)

  • Balancing and production of glucose as needed.

  • Regulation of blood levels of amino acids, which form the building blocks of proteins

  • Processing of hemoglobin for distribution of its iron content. (The liver stores iron.)

  • Conversion of poisonous ammonia to urea. (Urea is one of the end products of protein metabolism that is excreted in the urine.)

  • Clearing the blood of drugs and other toxic substances

  • Regulating blood clotting

  • Resisting infections by producing immune factors and removing certain bacteria from the bloodstream

  • Clearance of bilirubin. An accumulation of bilirubin will turn the skin and eyes yellow.

When the liver has broken down harmful substances, their by-products are excreted into the bile or blood. Bile by-products enter the intestine and ultimately leave the body in the feces. Blood by-products are filtered out by the kidneys and leave the body in the form of urine.

Online Medical Reviewer: Dozier, Tennille, RN, BSN, RDMS
Online Medical Reviewer: MMI board-certified, academically-affiliated clinician
Date Last Reviewed: 4/27/2014
© 2000-2014 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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