216 THE CIRCULATORY APPARATUS 



mesenteric veins behind the head of the pancreas, 

 and ascends behind the duodenum and between the 

 layers of the lesser omentum. Here it runs behind 

 the hepatic artery and bile duct. Accompanied by the 

 hepatic plexus of nerves and lymphatics, all enclosed 

 in Glisson's capsule, it then enters the transverse 

 fissure, forming near the right end the "sinus," and 

 divides into : A right branch, to the right lobe, which 

 distributes branches entering the hepatic substance 

 with the hepatic arterial branches and ducts; and a 

 left branch, distributed like the right. The portal vein 

 also drains the pyloric, cystic, gastric, and par- 

 umbilical veins. The portal vein and its tributaries 

 convey blood to the liver from the following organs 

 spleen, pancreas, stomach, gall-bladder, umbilicus, 

 duodenum, small and large intestines, appendix, and 

 upper portion of the rectum. 



The vena portse receives the following tributaries: 



The superior mesenteric corresponding to the artery 

 of the same name, receiving also the right gastro- 

 epiploic win, besides branches accompanying those 

 of the artery. It joins the splenic vein. 



The splenic arises by five or six vessels uniting after 

 leaving the hilum, and runs to the right below the 

 artery, joining the above at a right angle to form the 

 vena portae. It receives the vasa brevia, left gastro- 

 epiploic, and pancreatic branches, and the inferior 

 mesenteric vein. 



The inferior mesenteric vein corresponds in branches 

 and course to the artery, and empties into the angle 

 of junction of the two preceding. 



The pyloric runs with the pyloric branch of the 

 hepatic artery, and joins the vena portse; also the 

 gastric vein which accompanies the gastric artery and 

 receives the esophageal branches, joins the vena portas 

 above the former. 1 



1 See Chapter on Absorption, page 287, for description of the func- 

 tion of the portal system. 



