. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 122 COMPARATIVE MORPHOLOGY OF VERTEBRATES. to that organ. The dorsal mesentery is usually more complete, but it is interrupted in various groups. Its regions are called mesogaster, mesentery proper, mesocolon, mesorectum, etc., accordingly as they support stomach, small intestine, colon and rectum. Except in the cyclostomes the alimentary canal is bent on itself and the bends are connected by similar membranes, here called omenta. These also have special names. Thus the gastrohepatic omentum (small omentum) con
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 122 COMPARATIVE MORPHOLOGY OF VERTEBRATES. to that organ. The dorsal mesentery is usually more complete, but it is interrupted in various groups. Its regions are called mesogaster, mesentery proper, mesocolon, mesorectum, etc., accordingly as they support stomach, small intestine, colon and rectum. Except in the cyclostomes the alimentary canal is bent on itself and the bends are connected by similar membranes, here called omenta. These also have special names. Thus the gastrohepatic omentum (small omentum) connects stomach and liver; then there are gastro- splenic, doudeno-hepatic omenta, etc., while in mammals there is a great omentum, a double fold of mesogaster and mesocolon which connects the stomach. ha FIG. 131.—Diagrammatic section of a vertebrate to show the relation of the body walls, etc. av, aorta; c, ccelom; e, ectoderm; ep, epaxial muscles; g, gonads; ha, haemal arch; hp, hypaxial muscles; i, intestine; mes, mesentery; n, nephridium; o, omentum; r, rib; so, somatopleure; sp, splanchnopleure; v, vertebra. with the colon. This forms a large sac, the bursa omentalis, which opens into the rest of the body cavity by a small foramen of Winslow (foramen epiploicum) near the hinder end of the liver. Homologous structures are formed in connection with other organs. Thus in the formation of the heart there are formed temporary membranes, the meso- cardia, connecting it with the walls of the pericardium; while in the mammals a mediastinum, between the two pleural cavities binds the pericardium to the ventral body wall. Frequently the reproductive organs project so far into the body cavity that the serosa meets behind them, forming similar supports, mesovaria for the ovaries, mesorchia for the testes. The primitive body cavity extends from a point just behind the head back to the vent. It soon becomes divided into two cavities. Just in front of the liver a pair of blood-vessels,
Size: 1477px × 1692px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
