ABSTRACT
The structural organization of the liver reflects its function that is to serve as a guardian situated between the digestive tract and the rest of the body. Formation of bile requires the liver to have an exocrine gland structure. In addition, the liver also plays an important role in the body’s defense against macromolecules and particulate materials such as bacteria. The liver constitutes approximately 2–5% of body weight in the adult man and 5% at birth. Hepatocytes, estimated to number 250 billion in normal adult human liver, comprise about 80% of the total cellular population and 80% of hepatic tissue volume. The liver receives blood through the portal vein and hepatic artery. The former accounts for 75–80% and the latter 20–25% of the total hepatic blood flow, which is about one-quarter of cardiac output. During the seventeenth century, Wepfer and Malpighi described small clumps of hepatic tissue adhering to minute blood vessels as the structural unit of the liver.
