About the Liver, Bile Duct and Pancreas
Overview of the Hepato-Pancreato-Biliary System
The hepato-pancreato-biliary system is made up of the liver and its bile duct and the pancreas. The liver is a large organ in that sits under the ribs on your right side. It is divided into a right and left lobes. It is a very important organ with several jobs. The liver makes bile which helps in digestion. It also helps break down the food we eat and stores this as sugar. The liver makes substances that allow blood to clot. Finally, the liver serves as the major organ to process and filter medications and toxins. Of note, the liver is also the only organ that can partially grow back after cutting part of it out.
The biliary system is made up of the bile ducts and the gallbladder. The bile ducts carry bile from the liver to the small intestine. The gallbladder stores the bile until you eat at which point it is released from the gallbladder to help you digest the fats in the food. The bile ducts can be divided into those inside the liver (intrahepatic), outside the liver (extrahepatic) and right where the duct comes out of the liver (hilar).
The pancreas is an organ that sits in the upper abdomen, behind the stomach and the colon. It has two main functions. The first job of the pancreas is to make insulin which helps control the body’s sugars. This is called the “endocrine” function. The second job of the pancreas, called the “exocrine” function, is to make enzymes which help with digestion.
The liver is the largest solid organ within the abdomen. It is located in the right upper quadrant and protected by the lower portion of the right rib cage. The liver has dual blood supply, consisting of the portal, i.e., blood flowing from the intestine to the liver, and arterial, i.e., fresh blood pumped directly from the heart. Although the liver appears as one big organ, anatomically it is very complex and is divided into 2 halves, the right and left, which are further divided into four segments each. The liver is one of the most important organs in the human body, and currently there are no replacement machines to mimic the function of the liver. The liver has the unique ability to regenerate itself, i.e., grow in size, to sustain its function after portion has been removed. The liver performs some of the most important functions, from detoxification and excretion of toxins from the human body, to secretion of certain proteins that help with immune function and blood clotting. The liver also makes bile, which is secreted into the gut and helps in absorption of certain vitamins and minerals.
The liver is the largest and one of the most complex organs in the human body. Anatomically the liver is divided into two halves, right and left, and each half divided into four segments each. The liver performs an important function of excretion of toxins generated by day-to-day functions. The toxins are excreted from the body in the form of bile. Bile is carried from the liver and excreted into the intestine through a structure called the bile duct. The bile duct is a hollow tube, like a straw. Each bile duct originates in a segment of the liver, and they come together eventually to form the right and left main bile duct, which in turn form the common bile duct.
The portion of the bile duct that is within the liver is called the intrahepatic bile duct, while the portion of the bile duct, or the common bile duct, that is located outside the liver is called the extrahepatic bile duct. The area where the bile duct exits the liver and is not surrounded by liver tissue is called the hilum of the liver. This area also includes blood vessels, i.e., artery and portal vein entering the liver. Towards the end of its course, the bile duct is surrounded by the pancreas and is called the distal common bile duct. The gallbladder is connected to the bile duct by the cystic duct, which is a hollow tube. The gallbladder is shaped like a balloon and is responsible for concentrating and storing bile. Bile duct cancer, or cholangiocarcinoma, can arise anywhere in the course of the bile duct. When it originates within the liver, or at the hilum, resection of a portion of the liver along with the bile duct is necessary, while distal bile duct cholangiocarcinoma requires removal of a portion of the pancreas.
The pancreas is a solid organ located in the upper abdomen behind the stomach. It is flat and long like a fish, with the head of the pancreas located to the right of the midline of the abdomen, while the body and tail of the pancreas extend to the left of the abdomen. The head of the pancreas is attached to the duodenum, while the tail of the pancreas is near the spleen. A portion of the head, known as the uncinate process, is near blood vessels that supply blood to the intestine, liver, spleen and pancreas. Therefore, tumors, depending on the location within the pancreas, often involve these critical blood vessels. The pancreas’s two main functions are known as the endocrine and exocrine functions. The endocrine function is mostly related to maintaining a steady blood glucose level during fasting and after meals. Pancreas juices help in digestion of protein, i.e. meats and fats, and this comprises the exocrine or digestive function. Pancreas insufficiency is due to undigested fats and meat in stool, which can present as diarrhea with stools floating on water and can be foul smelling.
The spleen is a dark purple-red colored organ that sits in the left upper quadrant of the abdomen. It is in contact with the diaphragm, colon, and pancreas, fixed in position by fibrous bands and protected laterally by the left lower ribs. The spleen has a primary and secondary arterial and venous blood supply that delivers blood to an internal mesh like network of tissue. 10-20% of the time, spleen tissue can be found in other places in the abdomen. The spleen has two main functions. The first is a hematologic function. A process of removing aging and abnormal red blood cells from the blood system, in addition to hematopoiesis, which is the process of making red and white blood cells. The second function job of the spleen is an immunologic function. This process involves producing white blood cells which are responsible for protecting the body against harmful bacteria and cells.
The stomach is a muscular organ situated between the esophagus and small intestine. It is located in the upper abdomen on the left side. After eating, food travels down the esophagus and enters the stomach. The stomach secretes acid and enzymes to begin digesting food. The muscles of the stomach churn the food to mix it with the acid and enzymes. After some time, the stomach squeezes the digested food out through a muscular valve called the pylorus and into the small intestine where additional digestion and absorption occur.