Fistulas and lobectomies and splenectomies! OH MY!

Hepatic Portal vein

            The liver has a dual blood supply like that of the lungs.  The hepatic portal vein is like the workhorse of the liver, supplying 70-80 percent of the blood.  The blood that enters the liver contains about 40 percent more oxygen then those in the systemic system.  This is due to the oxygen need of the parenchyma cells in the liver.  20-25 percent of the blood to the liver comes from the hepatic artery, and is first given to non-parenchymal structures first.  The hepatic portal vein is made from the superior mesenteric and splenic veins.  It ascends from the IVC in part of the hepatic portal triad in the heptoduodenal ligament.  The hepatic vein is divided into divisions throughout the lobes of the liver, and is called the right, intermediate and left hepatic veins. 

An interesting fact about the hepatic system is that the right and left hepatic portal veins do not communicate.  This discovery allowed for doctors to perform hepatic lobectomies with little bleeding.  Now using laser surgery, doctors perform hepatic segmentectomies now when a portion of the liver is injured.  The hepatic veins provide guidance to the fissures where the doctors will cut. 

Importance of the Spleen

Before birth, the spleen is a vital organ for making blood.  After birth, the spleen is used to identify red blood cells, and determine whether they need to be destroyed or not.  The spleen also serves as a blood reservoir for the body, and stores red blood cells and platelets.  The spleen contains red pulp and white pulp.  The red pulp is involved in the recognition of the red blood cells and there destruction once they reach the proper age.  The white pulp is responsible for filtering antigens and producing lymphocytes. 

            When blunt trauma occurs to the spleen, it is an emergency situation and must be surgically repaired due to excessive bleeding out.  Either a total or partial splenectomy will be performed.  If a partial is performed, regeneration can occur like that of the liver.  However, if total removal must occur, then other reticuloendothelial organs, like the liver, carry out the functions that the spleen provides.  One major drawback of loosing your spleen is that you are more susceptible to certain bacterial infections. 

Gallbladder

The gallbladder lies on the visceral surface of the liver and is in very intimate contact with the duodenum.  The gall bladder can hold up too 50 ml of bile at one time.  The cystic duct is connected to the neck of the gallbladder and empties into the hepatic duct.  An important part of the gallbladder is the spiral folds at the neck.  These folds allow the cystic duct to remain open.  This allows movement of bile out of the gallbladder into the duodenum when the gallbladder contracts or allows for bile to be moved back into the gallbladder when the sphincter of the bile duct is closed at the distal end.  These spirals fold also aides in sudden dumping of bile when major pressure occurs in the abodominopelvic cavity, like when you sneeze or cough. 

When a gallbladder has been inflamed due to a trapped gallstone, the walls of the gallbladder can begin to break down.  A possible complication that can occur in addition to this problem is the formation of a fistula.  A fistula is a passageway between two endothelial-lined organs that usually are not connected.  In the case of the gallbladder and the duodenum, This newly created passageway would allow the gallstone to move into the duodenum causing a bowel obstruction or impaction in the digestive tract.  Another problem would be the movement of gas from the duodenum into the gallbladder. 

Sources 

of Information:

Clinically Oriented Anatomy Book

http://en.wikipedia.org/wiki/Fistula