. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. C rSl FIG. 283.—Three stages in the development of the hepatic portal system. .4, primitive; B, liver tubules beginning to develop, right omphalomesenteric interrupted; C, definitive condition, liver not indicated, dc, Cuverian ducts, hp, hepatic portal vein; hv, hepatic vein; /, liver; lo, ro, left and right omphalomesenteric veins; si, subintestinal veins; sv, sinus venosus. retains its primitive importance on the side of the liver and is known as the ductus venosus (Arantii), but soon this preeminence is los
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. C rSl FIG. 283.—Three stages in the development of the hepatic portal system. .4, primitive; B, liver tubules beginning to develop, right omphalomesenteric interrupted; C, definitive condition, liver not indicated, dc, Cuverian ducts, hp, hepatic portal vein; hv, hepatic vein; /, liver; lo, ro, left and right omphalomesenteric veins; si, subintestinal veins; sv, sinus venosus. retains its primitive importance on the side of the liver and is known as the ductus venosus (Arantii), but soon this preeminence is lost and all blood coming from behind passes through the network of cap- illaries in the liver before it enters the heart (fig. 283, C). Such a capillary circulation occurring in the course of a vein is known as a portal system, and this one occurring in the liver is the hepatic portal circulation. It consists of the vessels bringing the blood to the liver (portal vein)—a part of the original omphalomesenteric—the capil- lary vessels and the bases of both omphalomesenterics, now known as the hepatic veins, which convey the blood from the liver to the heart. In eggs with a large yolk (elasmobranchs, sauropsida) the presence of this large food supply exercises a modifying influence on these ventral veins (fig. 284). From the junction of the omphalomesenteric and the subintestinal veins a pair of large vitelline veins run out into the yolk sac, over the yolk, and play a large part in the transfer of material to the growing embryo. The distal parts of these veins follow the margin of the yolk sac, forming a tube (sinus terminalis) into which. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kingsley, J. S. (John Sterling), 1854-1929. Philadelphia, P. Blakiston's son & co.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
