liver

(noun)

A large organ in the body that stores and metabolizes nutrients, destroys toxins, and produces bile. It is responsible for thousands of biochemical reactions.

Related Terms

Examples of liver in the following topics:

  • The Liver

    • The liver makes bile, which is essential for the digestion of fats.
    • The liver normally weighs between 1.3—3.0 kilograms and is a soft, pinkish-brown organ.
    • The liver is supplied by two main blood vessels on its right lobe: the hepatic artery and the portal vein.
    • The bile produced in the liver is essential for the digestion of fats.
    • Bile is formed in the liver, and it is stored in the gallbladder or released directly into the small intestine.

  • Anatomy of the Liver

    • The liver is located in the abdomen and has four lobes.
    • The liver lies to the right of the stomach and overlies the gall bladder.
    • The lobes are further divided into lobules, the functional units of the liver.
    • The spatial relationship between the liver, stomach, gall bladder, and pancreas.
    • The liver is seen above the stomach, gall bladder, and pancreas.

  • Liver Function

    • The various functions of the liver are carried out by the liver cells or hepatocytes.
    • The bulk of the lipoproteins are synthesized in the liver.
    • The liver breaks down insulin and other hormones.
    • A healthy liver can break down alcohol.
    • However, the overstressed liver of an alcoholic may become clogged with fats that adversely affect liver function.

  • Histology of the Liver

    • A hepatocyte is the main tissue cell of the liver and makes up 70–80% of the liver's cytoplasmic mass.
    • Hepatocytes are derived from hepatoblasts, the precursor stem cell of the liver that divides to produce new hepatocytes.
    • The liver is capable of complete regeneration from as little as 25% of the original organ.
    • Describe the layers of the gallbladder and the histology of the liver

  • Blood Supply to the Liver

    • In the hepatic portal system, the liver receives a dual blood supply from the hepatic portal vein and the hepatic arteries.
    • In the hepatic portal system, the liver receives a dual blood supply from the hepatic portal vein and hepatic arteries.
    • The hepatic arteries supply arterial blood to the liver and account for the remainder of its blood flow.
    • Blood flows through the liver tissue and empties into the central vein of each lobule.
    • An image of a liver with the hepatic veins labeled.

  • Hepatic Portal Circulation

    • The hepatic portal system is responsible for directing blood from parts of the gastrointestinal tract to the liver.
    • It functions to supply the liver with metabolites and ensures that ingested substances are processed in the liver before reaching the systemic circulation, limiting the damage ingested toxins may cause.
    • Blood from either source passes into cavities between the hepatocytes of the liver called sinusoids, which feature a fenestrated, discontinuous endothelium allowing for the effecient transfer and processing of nutrients in the liver.
    • The liver consumes about 20% of the total body oxygen when at rest.
    • Sinusoid of a rat liver with fenestrated endothelial cells.

  • Hepatitis

    • Hepatitis is the inflammation of the liver.
    • Hepatitis is the inflammation of the liver.
    • The occurrence of jaundice indicates advanced liver damage.
    • When the liver is inflamed, levels of certain liver enzymes that are found in the blood will be elevated.
    • Alcoholic hepatitis can vary from mild with only liver test elevation to severe liver inflammation with development of jaundice and liver failure.

  • Associated Organs

    • The pancreas, liver, and gallbladder are the essential associated organs of the digestive system.
    • The pancreas, liver, and gallbladder are organs that are essential for digestion.
    • It is connected to the liver and the duodenum by biliary tree.
    • The liver and gallbladder are connected via the cystic duct, the liver and pancreas are connected via the pancreatic duct, and all three enter the duodenum at the common bile duct,
    • Differentiate among the roles played by the pancreas, liver, and gallbladder in digestion

  • Waste Management in Other Body Systems

    • In addition to the kidneys, the liver, skin, and lungs also have important roles in the excretion of waste from the body.
    • The skin, lungs, and liver are the main waste removal organs outside of the non-renal system; however, their ability to remove wastes is generally less than that of the renal system.
    • The liver has many vital functions, including a role in digestion, protein synthesis, and nutrient and vitamin storage.
    • The liver also plays an important function in the management of body waste.
    • While the liver may breakdown or neutralize waste in a different and safer form for the body, it doesn't directly remove the waste from the body.

  • Insulin Secretion and Regulation of Glucagon

    • Glucose is stored in the liver in the form of the polysaccharide glycogen, which is a glucan.
    • Liver cells have glucagon receptors and when glucagon binds to the liver cells they convert glycogen into individual glucose molecules and release them into the bloodstream—this process is known as glycogenolysis.
    • As these stores become depleted, glucagon then encourages the liver and kidney to synthesize additional glucose by gluconeogenesis.
    • Glucagon also turns off glycolysis in the liver, causing glycolytic intermediates to be shuttled to gluconeogenesis that can induce lipolysis to produce glucose from fat.
    • It's main role is to promote the conversion of circulating glucose into glycogen via glycogenesis in the liver and muscle cells.