Fig. 42—A front view of the heart showing coronary arteries. (Spalteholz)
Fig. 43—A back view of the heart showing the coronary sinus, and vessels entering and leaving. (Spalteholz)
The Portal Circulation.
—This circulation is of little or no value to the embalmer, as no part of it is directly required to supply any of the tissues with embalming fluid.
The portal circulation is formed by the superior mesenteric vein and the splenic vein uniting to form the portal vein. The inferior mesenteric vein runs into the splenic vein; the gastric and cystic veins run into the portal veins. The portal vein ends in capillaries in the liver, where certain important changes take place, namely, the taking out of the bile.
The portal vein and its tributaries are unlike the veins in the general circulation, as there are no valves. Their function in life is to gather up food or nutrition for the blood, and to the embalmer is of no special importance, only to know how this circulation is made up. The vessels that convey blood to the liver in life and the fluid in death are discussed under the liver.
After death, about one-fourth of the blood of the body is to be found in the portal system. This blood can in no way be removed, and this is one of the reasons why the embalmer is not able to draw more blood than he does.