Key takeaways

  • The liver, the body’s largest solid organ, plays a vital role in over 500 bodily functions, including detoxification and nutrient metabolism.
  • Located in the upper right abdomen, this triangular organ is unique among visceral organs for its remarkable ability to regenerate itself, even after significant tissue loss.
  • Maintaining a healthy lifestyle, including a balanced diet and regular exercise, is crucial for supporting liver function and its regenerative capabilities, helping to prevent various liver diseases.

The liver is part of the digestive system and is the largest internal solid organ in the body.

It performs over 500 tasks, including detoxification, protein synthesis, and the production of digestive enzymes.

A person’s liver is in the upper right section of the abdomen and sits below the diaphragm. It typically weighs around 3 pounds, though this can vary from person to person. The skin is the only organ heavier and larger than the liver.

The liver is roughly triangular and consists of two lobes: a larger right lobe and a smaller left lobe. The falciform ligament separates the lobes. This ligament is a band of tissue that keeps the liver anchored to the diaphragm.

A layer of fibrous tissue called Glisson’s capsule covers the outside of the liver. The peritoneum, a membrane that lines the abdominal cavity, then covers this.

This helps hold the liver in place and protects it from physical damage.

Blood vessels

Unlike most organs, the liver receives blood from two major sources. The portal vein brings in nutrient-rich blood from the digestive system, and the hepatic artery carries oxygenated blood from the heart.

The blood vessels divide into small capillaries, with each ending in a lobule. Lobules are the functional units of the liver and consist of millions of cells called hepatocytes.

Three hepatic veins remove blood from the liver.

The liver is a gland that has many functions in the body. It is difficult to give a precise number, but it may have more than 500 distinct roles.

The major functions of the liver include:

  • Bile production: Bile helps the small intestine break down and absorb fats, cholesterol, and some vitamins. Bile consists of bile salts, cholesterol, bilirubin, electrolytes, and water.
  • Absorbing and metabolizing bilirubin: The breakdown of hemoglobin, which is the protein in red blood cells that carries oxygen and gives blood its red color, forms bilirubin. The liver or bone marrow stores iron released from hemoglobin, which is used to make the next generation of blood cells.
  • Supporting blood clotting: Vitamin K is necessary for the production of coagulation factors that help the blood to clot. Bile forms in the liver and is essential for vitamin K absorption. The liver must produce enough bile to make clotting factors.
  • Fat metabolization: Bile breaks down fats, making them easier to digest.
  • Metabolizing carbohydrates: The liver stores carbohydrates known as glycogen. The body can break down glycogen into glucose. Glucose, or sugar, is released into the bloodstream to regulate blood sugar levels and for a quick burst of energy.
  • Vitamin and mineral storage: The liver stores significant amounts of fat-soluble vitamins, including vitamins A, D, E, K, and B12. The liver stores iron from hemoglobin as ferritin, ready to make new red blood cells. The liver also stores and releases copper.
  • Helps metabolize proteins: Bile helps break down proteins for digestion.
  • Filters the blood: The liver filters and removes compounds from the body, including hormones such as estrogen and aldosterone, as well as compounds from outside the body, including alcohol and other drugs.
  • Immunological function: The liver is part of the mononuclear phagocyte system. Cells involved in immune activity, Kupffer cells, are abundant in the liver. These cells destroy disease-causing viruses, bacteria, or other microorganisms that might enter the liver through the gut.
  • Albumin production: Albumin is the most common protein in blood serum. It transports fatty acids and steroid hormones to help maintain proper pressure and prevent bleeding from blood vessels.
  • Synthesis of angiotensinogen: This hormone raises blood pressure by narrowing blood vessels when renin, an enzyme produced in the kidneys, is activated.

Because of the liver’s importance and its functions, evolution has ensured that it can regenerate rapidly as long as it is kept healthy. All vertebrates, from fish to humans, can regenerate their livers.

The liver is the only visceral organ capable of regeneration after partial removal or chemical injury. It can regenerate completely as long as at least 25% of the tissue remains. The liver can regrow to its previous size and ability without any loss of function during the growth process.

Mice can regrow liver tissue to its original size and restore function within 7 to 10 days. In humans, the process takes slightly longer, but regeneration can still occur in 8 to 15 days.

Researchers suggest that surgical removal of the right or left lobe of the liver results in complete restoration of liver mass after 3 months, while maximum cellular activity happens 7 to 10 days after the procedure.

Over the following few weeks, the new liver tissue becomes indistinguishable from the original tissue.

A number of compounds are responsible for liver regeneration, including growth factors and cytokines. Some of the most important compounds in the process appear to be, but are not limited to:

  • hepatocyte growth factor
  • insulin
  • transforming growth factor-alpha
  • epidermal growth factor
  • interleukin-6
  • norepinephrine

An organ as complex as the liver can experience a range of difficulties. A healthy liver functions very efficiently. However, the consequences can be dangerous or even fatal in a diseased or malfunctioning liver.

Examples of liver disease include:

  • Hepatitis: Hepatitis is the name given to a general infection of the liver, and viruses, toxins, or an autoimmune response can cause it. An inflamed liver characterizes this condition. In many cases, the liver can heal on its own, but severe liver failure can sometimes occur.
  • Alcohol-associated liver disease: Drinking too much alcohol over long periods can cause liver damage.
  • Fatty liver disease: This usually occurs alongside obesity or excessive alcohol use. In fatty liver disease, fat vacuoles accumulate in liver cells. Nonalcoholic fatty liver disease occurs when alcohol use is not the cause.
  • Primary sclerosing cholangitis (PSC):PSC is a rare but serious disease causing bile duct inflammation (cholangitis), leading to scarring (sclerosis), bile duct narrowing, and a buildup of bile in the liver. There is currently no cure, and the cause is unknown.
  • Gilbert’s syndrome: A genetic disorder affecting 4% to 16% of the population. In Gilbert’s syndrome, the body does not fully break down bilirubin. Mild jaundice can occur, but the disorder is harmless.
  • Fascioliasis:A tropical disease in which a parasitic worm, known as a liver fluke, causes the bile ducts to become blocked. The liver fluke can lie dormant in the liver for months or even years. This is very rare and does not significantly affect people in the U.S. and Canada.

Consequences of long-standing liver disease may include:

  • Cirrhosis:This occurs when scar tissue replaces liver cells, a process known as fibrosis. Toxins, alcohol, and hepatitis are some of the many factors that cause this condition. Eventually, fibrosis can lead to liver failure because the functionality of liver cells is destroyed.
  • Liver cancer: The most common types of liver cancer are hepatocellular carcinoma and cholangiocarcinoma. The leading causes are alcohol and hepatitis. It is the sixth most common form of cancer globally and the third most frequent cause of cancer death around the world.

Below are some recommendations from the American Liver Foundation (ALF) to help keep the liver working as it should:

  • Diet: As the liver is responsible for digesting fats, consuming too many can overwork the organ and divert its resources from other tasks. This also has links to fatty liver disease.
  • Avoiding alcohol: Drinking too much alcohol causes cirrhosis of the liver over time, with more health studies showing that avoiding alcohol is better for overall health.
  • Avoiding recreational drugs: Recreational drugs can overload the liver with toxins. Avoiding these substances can allow the liver to perform its necessary functions without impediment.
  • Caution when mixing medications: Some prescription drugs and natural remedies can negatively interact. Additionally, mixing drugs with alcohol puts significant pressure on the liver.
  • Protection against airborne chemicals: Exposure to airborne chemicals can cause liver damage. When painting or using strong cleaning or gardening chemicals, the area should be well ventilated, and people should wear a mask.
  • Travel and vaccinations: Vaccination is essential if a person travels to an area where hepatitis A or B might be a concern. Malaria grows and multiplies in the liver, and yellow fever can lead to liver failure.
  • Safe sex: There is no vaccination for hepatitis C. Safe sex practices can help prevent the disease.
  • Avoid exposure to blood and germs. Receive medical attention if exposed to another person’s blood.

Despite its ability to regenerate, the liver depends on being healthy to do so. With lifestyle choices and dietary measures, the liver can help protect itself in most cases.

The liver is the largest solid internal organ in the human body.

It is part of the digestive system and plays an essential role in removing toxins from the blood, metabolizing nutrients, and supporting immune function.