130 ANATOMY AND PHYSIOLOGY FOR NURSES 



divided as follows: Great cardiac vein, posterior cardiac 

 vein, anterior cardiac vein, and venae Thebesii. They 

 collect the blood from the several portions of the heart, 

 and terminate in the right auricle. 



THE PORTAL CIRCULATION 



The portal circulation is a part of the general sys- 

 temic circulation. The stomach, intestines, pancreas, 

 and spleen receive their arteries from the aorta, and the 

 blood, on leaving these, is received into various veins, 

 which unite to form the portal vein; this enters the sub- 

 stance of the liver and breaks up into numerous capillaries. 

 The portal vein not only returns venous blood from the 

 gastro-intestinal tract, but also carries nutritive products 

 to the liver, which are there still further elaborated. 

 The blood is then collected by the hepatic vein, which 

 opens into the inferior vena cava just before the vessel 

 enters the right auricle. 



The portal system of veins is formed by the union 

 of the superior and inferior mesenteric, splenic, and gas- 

 tric veins, and collects the blood from the digestive viscera. 

 The resulting trunk divides in its course to the transverse 

 fissure of the liver into a branch each for the right and 

 left lobe, which ramify to form plexuses in the liver. 

 The blood from the hepatic artery furnishes blood to this 

 vein in the interior of the liver, and exterior to this organ 

 the vein unites with the pyloric and coronary veins. 

 The blood so collected passes through the liver and, as 

 previously stated, is transmitted to the inferior vena 

 cava by the hepatic vein. 



THE PULMONARY CIRCULATION 



The pulmonary artery, carrying venous blood, 

 leaves the right ventricle and divides into branches, 

 one for each lung. Inside the lung this vessel breaks 



