77//'; lii.ooi) sysTK.\r 2\) 



those organs are called portal veins and are distinguished by pro- 

 fixing the name of the organ. 



The Renal Porlal System. — Hcmovc the skin from the dorsal 

 surface of the left thigh, separate the nmscles by tearing the 

 connective tissue between them. Between the two larger muscles 

 will be found a smaller one which may be transected at its middle, 

 rnderneath this small muscle can be seen the femoral vein 

 which drains the hind limb. Remove such muscles and portions 

 of the skin and body wall as are necessary to trace this vein to a 

 point on the posterior wall of the body cavity where it forks giving 

 off a dorsal branch, the re7ial portal vein, and a ventral branch, 

 the pelvic vein. Tear the peritoneum along the outer margin of 

 the kidney so as to expose this organ. Now trace the left renal 

 portal vein along the outer margin of the kidney and note that it 

 breaks up into capillaries within this organ. Through what 

 vessels does the blood emerge from the kidneys, and by what 

 main trunk does it reach the heart? The inght renal portal 

 corresponds in its course and branches to the left one. Uncover 

 this vessel and also the right. 



The Hepatic Portal System. — The union of the two pelvic 

 veins, one from each side of the body, forms the ventral abdominal 

 or the vein which was eariier dissected from the ventral body 

 wall. The hepatic portal system is formed partly by the ventral 

 abdominal vein, which brings to the liver blood from the hind 

 limbs; and partly by veins returning blood from the alimentary 

 canal and its appendages. Trace the ventral abdominal vein 

 cephalad to the liver and note that it divides into right and left 

 branches, which enter the right and left lobes of the liver, respec- 

 tively. The hepatic portal vein is a large vein which runs in the 

 mesentery and joins the ventral abdominal vein at its point of 

 division into right and left branches, giving off, before doing so, a 

 branch to the left lobe of the Hver. It carries to the liver the 

 blood from the walls of the ahmentary canal and is formed by the 

 union of the (1) gastric veins, from the stomach, the (2) intestinal 

 veins, from the whole length of the intestine both smalkmd largo, 

 and (3) the splenic vein, from the spleen. This usually joins one 

 of the intestinal veins. 



Reduce this dissection to the simple principle of "region 

 drainage" illustrated in Fig. 1. 



On the plate showing outlines of some of the visceral organs, 

 indicate the course of one of the precaval veins and its tributaries 



