250 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



tracing its branches, tear the mesenteries which bind together the coils of tl 

 intestine as far as necessary and also strip off fat and lymph glands. Tl 

 intestinal vein is the large vessel collecting from the greater part of the sma 

 intestine. It runs in the middle of the mesentery, receiving many tributary 

 in its course. The branches from the jejunum immediately beyond tl 

 duodenum, however, enter the posterior pancreatico-duodenal vein. The vei 

 large ileocaecocolic vein collects from the ileum, appendix, caecum, and ascen< 

 ing and transverse colons. Chief among its tributaries are: the appendicuk 

 vein from the appendix; the anterior ileocaecal vein from the sacculus rotundu 

 proximal part of the caecum, adjacent ileum, and ascending colon; and tl 

 posterior ileocaecal vein from the distal part of the caecum, adjacent ileum, an 

 ascending colon. 



Draw, showing the portal system. 



Cat: The first tributary of the portal, on following the portal away froi 

 the liver, is the coronary vein from the stomach. This lies in the curve betwee 

 pylorus and stomach and at the lesser curvature is formed by the union of man 

 branches from both sides of the stomach. At about the same level as the entranc 

 of the coronary vein, the anterior pancreatico-duodenal vein enters the portal; 

 collects from the pancreas and duodenum. At the same level as the two precec 

 ing, the left gastro-epiploic vein enters, coming from the pyloric region and great* 

 curvature of the stomach and adjacent greater omentum. The three veins jus 

 described may enter the portal separately or may unite with each other in an 

 combination before entering the portal. Beyond the entrance of these small veir 

 the hepatic portal receives a large tributary, the gastrosplenic vein. This passt 

 to the left in the substance of the pancreas receiving one or more small midd* 

 gastro-epiploic veins from the stomach wall and omentum and a pancreatic vei 

 from the pancreas. Beyond these tributaries the gastrosplenic is formed by tt 

 union of two main branches, the right and left splenic veins. The left spleni 

 vein passes in the gastrosplenic ligament along the spleen, receiving branches froi 

 the spleen, the greater omentum, and several left gastro-epiploic veins from tt 

 omentum and stomach. The right splenic vein comes from the right end ( 

 the spleen, receiving also tributaries from the omentum and stomach wal 

 Beyond the entrance of the gastrosplenic vein the portal is known as the superit 

 mesenteric vein. This soon receives a small posterior pancreatico-duodenal vei 

 from the pancreas and distal part of the duodenum ; next, the inferior mesenter; 

 vein from the descending colon and rectum; and then is seen to be formed b 

 numerous converging intestinal branches from the small intestine, caecum, an 

 ascending colon. The lymph glands lying along the superior mesenteric vei 

 as well as. fat, should be removed in tracing the branches. 



Draw the hepatic portal system. 



It will be seen that the relations of the hepatic portal system are the same in mamma 

 as in all other vertebrates. The system conveys all of the venous blood from the digestr 



