Liver is the second largest organ in a human body, with metabolism as its primary function. Liver helps in about 500 known functions related to the human body ranging from storage of important nutrients to detoxification of the body. Liver is situated below and behind the right lower rib cage and weighs about 1.3-1.5 kgs in an adult male. Here are some interesting facts about one of the most important organs in human.
1. It’s an Energy Storehouse!
Liver stores glucose, the main energy providing molecule for human body, in the form of glycogen. Carbohydrate rich foods are broken down to smaller molecules and ultimately to glucose in the Gastrointestinal tract (GIT). Glucose is absorbed into the blood stream from GIT and this circulating glucose gets converted to glycogen (Glycogenesis) and stored in liver. About 100g of glycogen (about 400 calories) can be stored in the liver. When there is low circulating glucose in the blood, the liver glycogen is broken down to give glucose (Glycogenolysis). Glucose is also synthesized from amino acids, lipids etc (Gluconeogenesis). Tissues like brain depend exclusively on glucose for keeping up its activities. Liver also stores Vitamin A, D, E, K, Vitamin B12, Iron and Copper in small quantities.
Apart from carbohydrates, liver is also involved in metabolism (synthesis and breakdown) of proteins, lipid, and hormones. Liver produces important proteins like clotting factors, thrombopoietin, lipoproteins etc. It also synthesizes Albumin which is a major circulating protein in the blood. Liver helps in activation of vitamin D into its biologically active form. Liver plays a major part in lipid metabolism. Healthy liver contributes to good cholesterol balance in the body.
3. Site of blood synthesis in Fetus
Formation of blood cells is termed Haematopoiesis. Liver is the main site of haematopoiesis in the first 3 months (first trimester of pregnancy) of fetal life. Only after 32 weeks the bone marrow fully takes charge.
4. It can Regenerate!
Liver is the only visceral organ that can regenerate itself. As little as 51% of the original tissue is required for itself to regenerate.
Liver converts many drugs and chemicals into inactive metabolites and helps in their excretion. Dead cells and bacteria are phagocytosed by Kupffer cells present in the liver. It helps to break down hydrogen peroxide (oxidizing agent) into water and oxygen. Liver also helps in metabolising many drugs and hormones. Sometimes the breakdown by-products are more toxic than the parent drug which may result in toxicity.
6. Dual blood supply
Liver has 2 sources of blood, one from an artery called Hepatic artery and one from a venous system, called Portal vein. Hepatic artery brings oxygenated blood from the heart to the liver whereas the portal venous system brings nutrient rich blood supply from the GIT for further metabolism.
7. Liver also suffers!
Liver being exposed to various toxins, drugs and microorganisms also can suffer from many conditions that can leave a human being grasping onto his life support. It can range from fatty liver to hepatitis to more lethal cancers. Some of them may reveal themselves very late or only incidentally on routine investigations. So, a liver function test (LFT) done on a regular basis can help keep a lookout for these conditions. Jaundice is one of the symptoms of liver insult.