The Liver: A Vital Organ

The liver is one of the hardest-working organs in the body, quietly performing hundreds of essential functions every day. Among its most important jobs, the liver:

  • Produces bile, which helps the body break down and absorb fats
  • Manufactures proteins and blood-clotting factors the body depends on
  • Regulates blood sugar levels and stores extra glucose for later use
  • Partners with the stomach and intestines to digest food
  • Stores essential vitamins and minerals
  • Filters toxins and other harmful substances out of the bloodstream

How the Liver Works with Nearby Organs

The liver doesn’t work alone — it’s a central hub of the digestive system, connected to several other organs and vessels that help it do its job.

  • Biliary tree – A network of tubes that carries bile out of the liver and into the duodenum.
  • Bile ducts – Tubes connecting the liver to the small intestine, through which bile drains from the liver.
  • Common bile duct – Formed where the hepatic duct (from the liver) meets the cystic duct (from the gallbladder); it carries bile onward to the duodenum.
  • Duodenum – The first section of the small intestine, where bile mixes with food to aid digestion.
  • Gallbladder – A small organ that stores bile until it’s needed.
  • Spleen – Filters the blood and supports the immune system, helping the body fight infection.
  • Splenic vein – Carries blood from the spleen to the portal vein.
  • Portal vein – Delivers nutrient-rich blood from the digestive tract and spleen into the liver.
  • Inferior vena cava – A major vein that returns blood from the liver, legs, and kidneys to the heart.
  • Hepatic veins – Carry blood out of the liver into the inferior vena cava.
  • Hepatic artery – Supplies the liver with blood directly from the heart.

 

How Blood Flows Through the Liver

Every drop of blood leaving the intestines, stomach, and spleen passes through the liver for filtering. Blood enters through the portal vein and moves through an intricate network of progressively smaller vessels. As it flows past liver cells, those cells extract and process nutrients — converting them into proteins, sugars, and other compounds the body can use. The filtered blood then exits through the hepatic veins on its way back to the heart.

 

Liver Diseases

A wide range of conditions can affect liver health and can cause a variety of liver diseases. Viruses cause some of them, like hepatitis A, hepatitis B and hepatitis C. Others develop from certain medications, environmental toxins, or long-term alcohol use. When the liver responds to injury by forming scar tissue, the condition is known as cirrhosis. Jaundice-a yellowing of the skin and eyes-is often an early warning sign of liver trouble.

Cancer can also develop in the liver, and some liver conditions, like hemochromatosis, are inherited. If you’re experiencing symptoms, blood tests and a thorough evaluation by one of liver specialists can help determine the cause and the right path forward.

 

 Learn More About Liver Disease

Updated September 2026