The practice of obstetrics, designed for the use of students and practitioners of medicine . verse Section throughthe Umbilical Stalk of an Embryo MM.—Am., Amnion; , medtdlarygroove; V,V., umbilical veins; , um-bilical arteries; All., allantois; coe, coelom.{His.) 76 THE UMBILICAL CORD. 77 harmful pressure. It is derived from the mesodermic layer of the abdominalstalk. The gelatin has an irregular distribution, being thicker in some parts,where it forms the so-called false knots in the cord. This peculiar substanceconsists in great part of embryonic connective tissue, and is abu
The practice of obstetrics, designed for the use of students and practitioners of medicine . verse Section throughthe Umbilical Stalk of an Embryo MM.—Am., Amnion; , medtdlarygroove; V,V., umbilical veins; , um-bilical arteries; All., allantois; coe, coelom.{His.) 76 THE UMBILICAL CORD. 77 harmful pressure. It is derived from the mesodermic layer of the abdominalstalk. The gelatin has an irregular distribution, being thicker in some parts,where it forms the so-called false knots in the cord. This peculiar substanceconsists in great part of embryonic connective tissue, and is abundantlysupplied with branching cells-, the protoplasmic processes of which freely anas-tomose. The vessels of the-funis are originally two arteries and two two veins fuse early, leaving only one (Figs, no and 113), which comes to liebetween the arteries, so that the funic pulse can be easily felt. The vessels arecoiled from right to left, there being ten to twelve such turns. The spiral aspectthus given to the cord has been variously explained. One cause assigned is the fetal. Fig. 115.—Section of Injected Full-term Placenta, Cotyledon septum; a.,amnion; c, chorion; , decidua serotina; , muscle with injected vessels.—(Leopold.) movements; another, the fact that the growth of the blood-vessels in length ismore rapid than that of the connective tissue. The walls of both arteries and veinare of about equal thickness. The calibre of the vein is in excess of that ofthe arteries; and while the vein has semilunar valves, the arteries have circularvalves. The length of the cord averages about 22 inches (50 to 60 cm.), thoughwhen very long it may measure 64 inches (160 cm.), while the shortest on recordis inches (12 cm.). Its diameter is from -| to f of an inch ( to cm.).The strength of the cord varies; its tensile power at term ranging from 5 to12 pounds (2 to 5 kilograms). Its function is twofold: It carries nourishmentfrom the mother to the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectobstetrics, bookyear1
