. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. 124 THE CHORION develop, those associated with the allantois extend outward into the chorionic mesoderm and thence send branches into each villus. The second type of placentation, the hcemotrophic type, is thus estab- lished, the fetal blood contained in the vessels of the villi receiving nutrition through the walls of the villi from the maternal blood contained in the intervillous space, and, similarly, transferring waste products to it. At first, as stated above, the villi usually cover the
. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. 124 THE CHORION develop, those associated with the allantois extend outward into the chorionic mesoderm and thence send branches into each villus. The second type of placentation, the hcemotrophic type, is thus estab- lished, the fetal blood contained in the vessels of the villi receiving nutrition through the walls of the villi from the maternal blood contained in the intervillous space, and, similarly, transferring waste products to it. At first, as stated above, the villi usually cover the entire surface of the ovum, but later, as the ovum increases in size, those villi which are remote from the attachment of the belly-stalk to the chorion are placed at a disadvantage so far as their blood supply is concerned. Fig. 72.—Two Villi prom the Chorion of an Embryo of 7 mm. and gradually disappear, and this process continues until, finally, only those villi are retained which are in the immediate region of the belly-stalk (Fig. 69, C), these persisting to form the fetal portion of the placenta. By these changes the chorion becomes differenti- ated into two regions (Fig. 69, C), one of which is destitute of villi and is termed the chorion lave, while the other provided with them, is known as the chorion 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 McMurrich, J. Playfair (James Playfair), 1859-1939. Philadelphia : P. Blakiston's son & co.
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Keywords: ., bookautho, bookcentury1900, bookdecade1910, booksubjectembryology
