Anatomy of Liver
The liver is the largest organ, accounting for approximately 2% to 3% of average body weight. It weighs around 1400g in an adult female and about 1800g in the male. About 1.5 liters of blood go out of the liver every minute. Located in the right upper quadrant of the abdominal cavity beneath the right hemidiaphragm, it is protected by the rib cage and maintains its position through peritoneal reflections, referred to as ligamentous attachments.
The liver has the general shape of a prism or wedge, with its base to the right and its apex to the left. It is pinkish brown in color, with a soft consistency, and is vascular and easily friable. Its specific gravity is 1.05. It is connected to two large blood vessels, one called the Hepatic Artery and other called the Portal Vein. The Hepatic Artery carries blood from the Aorta, whereas the portal vein carries blood containing digested nutrients from the entire gastrointestinal tract and from the spleen and pancreas. These blood vessels subdivide into capillaries, which then lead to a lobule. Each lobule is made up of millions of hepatic cells that are the basic metabolic cells. Lobules are the functional units of the liver.
Functions of Liver
The liver supports almost every organ in the body and is vital for survival. It performs following functions:-
- Clearance of damaged red blood cells & bacteria by phagocytosis
- Nutrient management
- Synthesis of plasma proteins such as albumin, globulin, protein C, insulin-like growth factor, clotting factors etc.
- Biotransformation of toxins, hormones, and drugs
- Vitamin & mineral storage
Blood Flow Liver
Blood of Veins from the entire gastrointestinal tract (containing nutrients from the intestines) is brought to the liver by the hepatic portal vein. Branches of this vein pass in between the lobules and terminate in the sinusoids. Oxygenated blood is supplied in the hepatic artery. The blood leaves the liver via a central vein in each lobule, which drains in the hepatic vein.
- Hepatic Vein. The hepatic veins comprise of three large veins, which are the right hepatic vein, the middle hepatic vein and the left hepatic vein drain. Several short veins originating within the lobes of the liver as small branches unite to form the hepatic veins. These lead directly to the inferior vena cava, draining blood from the liver.
- Inferior Vena Cava. The inferior vena cava is formed by the coming together of the two major veins from the legs, the common iliac veins, at the level of the fifth lumbar vertebra. It collects blood from parts of the body below the diaphragm and conveys it to the right atrium of the heart.
- Hepatic Artery. It is an artery with origin in the celiac artery, with branches to the right gastric, gastroduodenal, and proper hepatic arteries. It provides oxygenated blood to the liver. It supplies 20% of the liver’s blood.
- Hepatic Portal Vein – The hepatic portal vein is a blood vessel that conducts blood from the gastrointestinal tract and spleen to the liver. It is a blood vessel which drains venous blood into the liver from the entire gastrointestinal tract. It supplies the remaining 80% of the liver’s blood.
Liver Related Diseases
The most common liver diseases include: