LIVER

It is the largest gland of the body. An adult human liver normally weighs between 1.4-1.6 kg (3.1-3.5 lb), and is a soft, pinkish-brown, triangular organ. It is reddish brown organ with four lobes of unequal size and shape. The liver is on the right side of the abdominal cavity just below the diaphragm and is connected to two large blood vessels, one called the hepatic artery and one called the portal vein. The hepatic artery carries blood from the aorta where as the portal vein carries blood containing digested food from the small intestine. These blood vessels subdivide into capillaries which then lead to a lobule. Each lobule is made up of thousands of hepatic cells which are the basic metabolic cells.

Functions of The Liver:
The various functions of the liver are carried out by the liver cells or hepatocytes.
Bile Formation – Bile is composed of water and electrolytes, and has significant amounts of lecithin, fatty acids, cholesterol, bilirubin and bile salts. It is formed by the hepatocytes and stored in the gallbladder. Bile is excretory; it aids in digestion by emulsification of fats in the intestines through bile salts.

Bilirubin Excretion – Bilirubin is a pigment derived from the breakdown of hemoglobin. Hepatocytes remove bilirubin from the blood. It is converted into urobilinogen that is excreted though our feces with the help of our hepatocytes.

Fat Metabolism – Fatty acids can be broken down for the production of energy and ketone bodies.

Vitamin and Iron Storage – Vitamin A, B and D, several of the B-complex vitamins and iron and copper are stored in liver in large amounts. The liver is responsible for immunological effects- the reticuloendothelial system of the liver contains many immunologically active cells, acting as a 'sieve' for antigens carried to it via the portal system.

Glucose Metabolism – It regulates the blood glucose concentration.

Protein Metabolism – It synthesizes most of the plasma proteins, including albumin, alpha and beta globulins, blood clotting factors, specific transport proteins and plasma lipoproteins. The liver produces albumin, the major osmolar component of blood serum. Vitamin K is required by the liver for synthesis of prothrombin and some of the other clotting factors. The liver synthesizes angiotensinogen, a hormone that is responsible for raising the blood pressure when activated by renin, a kidney enzyme that is released when the juxtaglomerular apparatus senses low blood pressure.

Ammonia Conversion – Amino acids from protein for gluconeogenesis results in the formation of ammonia as a byproducts. The liver converts ammonia, a potential toxin, into urea and can be excreted through urine.