The HPB (Hepato-Pancreato-Biliary) System
The hepato-biliary and pancreatic (HPB) systems are part of our gastro-intestinal system. It includes the liver, bile duct, gall bladder and pancreas. The HPB system secretes digestive juices into the intestine for digestion of ingested food. Diseases affecting the liver, gall bladder, bile ducts and pancreas are often grouped together as these organs are closely related and often abnormality in one of them effects the other. HPB surgery has therefore emerged as a super-speciality that deals with surgeries of the HPB system.
Bile from the liver is passed into the intestine through the bile ducts. The gall bladder temporarily stores the bile until it is needed for digestion of a large meal, when it is released. Similarly, the pancreas secretes the pancreatic juice into the intestine.
In addition to secreting the digestive juices, these organs serve very important functions to keep our body in a balanced state. The liver regulates acid-base balance, temperature, blood sugar balance, synthesis of proteins and detoxification of chemicals in our body. The pancreas secretes insulin, which is responsible for maintaining blood sugar.
Liver: Liver is the largest organ and the largest gland in our body. It is dark reddish brown in color and weighs about 1.2 kg. It is located in the right upper part of abdomen protected by the overlying rib cage. It consists of two main lobes, right and left, each of which have their own blood supply and bile ducts. Each lobe consists of several segments, each of which is a functional unit. Each of these sections have their own set of blood vessels and bile ducts, therefore, if one lobe or segment of the liver is affected by disease, it is possible to surgically remove that lobe, leaving behind the other lobe. Liver also has the remarkable and unique capacity to regenerate after any surgery or injury, therefore after removing one part of the liver, the remaining liver regenerates and grows in size. Surgeries of the liver are very complex because of its location in the abdomen, which makes it difficult to access. It is also very richly supplied with blood, and therefore the chances of bleeding during surgery are high. Liver surgeries should generally be performed by experienced surgeons at large volume centers only.
Functions of the liver:
More than 500 vital functions have been attributed to the liver, some of the well-known functions are:
Bile ducts: Bile duct is a tube-like structure that starts in the liver and ends in the intestine. It transports bile from the liver into the part of the intestine called the duodenum. The gall bladder also drains into the bile duct through the cystic duct. The bile duct also joins with the pancreatic duct before opening into the intestine. While the top half of the bile duct is in close proximity of the liver, the bottom half is associated the pancreas. Thus, diseases of the bile duct may also affect the liver and the pancreas.
Gall Bladder: The gall bladder is a pouch like organ that stores bile secreted by the liver temporarily. It is attached to the undersurface of the liver and has a globular body and narrow neck. It connects to the bile ducts through a small duct called as the cystic duct. Because of such close proximity of the gall bladder to the liver and pancreas, it commonly has to be removed in any surgery of the hepato-pancreato-biliary region.
Pancreas: Pancreas is a fish shaped, yellowish organ situated in the upper part of abdomen, behind the stomach. It is one of the most deep seated organ into the abdomen and is very richly supplied by blood vessels, therefore any surgery on pancreas carries a risk of bleeding. It is in close proximity to major blood vessels of the body and intestinal loops, therefore, diseases involving the pancreas can sometimes involve these structures. The pancreatic juice is secreted via the pancreatic duct into the intestine after it joins the bile duct. The pancreas also secretes important hormones such as insulin, glucagon and somatostatin.