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SPECIAL PHYSIOLOGY. 



parts of the organ, to the notch in its posterior border, where they 

 enter the ascending vena cava, by two or three main trunks, and thus 

 the blood from the liver, mixed with that from the lower half of the 

 body, ascends to the heart. 



Fig. 97. 



Fig. 97. Diagram to show the large vessels concerned in the so-called portal circulation. The trunk, or 

 body, is supposed to be divided down the middle line, so as to show the cavity of the thorax or chest, 

 above the arched diaphragm, and that of the abdomen below it. In the abdomen, 1. is the liver; *, the 

 stomach; d, a section of the duodenum, and pancreas; i, the small intestine; co, a part of the colon; r, 

 the rectum ; TO, the lower end of the spleen ; and k, the right kidney. The blood to all these parts, is 

 supplied through arteries which are branches of the abdominal aorta, marked a. From the rectum, r, 

 and the kidney, k, the blood is returned by veins, which end in the great ascending vein, named the 

 ascending vena cava, marked c, which conveys the venous blood directly through the diaphragm, and 

 into the right side of the heart, o. But the blood from the stomach, s; spleen, m ; duodenum and pan- 

 creas, d; small intestine, i; and large intestine, co (excepting the rectum, r), is collected by venous 

 branches, which end in a large venous trunk, named the vena portie, or portal vein,p, by which this 

 venous blood is conveyed to, and distributed by branches through, the liver. From this organ, it is 

 collected by other veins, which unite to form the hepatic veins, h, which then join the ascending vena cava, 

 c, and so reach the right side of the heart. 



The liver, like all secreting glands, is provided with ducts. These, 

 named the hepatic ducts, form, as they issue from the gland, two 

 principal trunks, one from the right, the other from the left lobe. 

 They emerge at the bottom of the portal fissure, where the two chief 

 divisions of the portal vein and hepatic artery enter, and then unite 

 to form a single duct, named the hepatic duct, ductus choledochus, or 

 bile duct. Having descended for about two inches, this joins another 



