Vitelline circulation: Difference between revisions
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[[Image:Gray22.png|thumb|Human embryo of 2.6 mm.]] | [[Image:Gray22.png|thumb|Human embryo of 2.6 mm.]] | ||
[[Image:Gray458.png|thumb|Diagram of the vascular channels in a human [[embryo]] of the second week. (After Eternod.) The red lines are the [[dorsal aortæ]] continued into the [[umbilical arteries]]. The red dotted lines are the ventral aorta, and the blue dotted lines the [[vitelline veins]].]] | [[Image:Gray458.png|thumb|Diagram of the vascular channels in a human [[embryo]] of the second week. (After Eternod.) The red lines are the [[dorsal aortæ]] continued into the [[umbilical arteries]]. The red dotted lines are the ventral aorta, and the blue dotted lines the [[vitelline veins]].]] | ||
{{WikiDoc Cardiology News}} | {{WikiDoc Cardiology News}} | ||
{{CMG}} | {{CMG}} | ||
Latest revision as of 15:53, 6 September 2012
Template:WikiDoc Cardiology News Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Vitelline circulation refers to the system of blood flowing from the embryo to the yolk sac and back again.
The yolk-sac is situated on the ventral aspect of the embryo; it is lined by entoderm, outside of which is a layer of mesoderm. It is filled with fluid, the vitelline fluid, which possibly may be utilized for the nourishment of the embryo during the earlier stages of its existence. Blood is conveyed to the wall of the sac by the primitive aortæ, and after circulating through a wide-meshed capillary plexus, is returned by the vitelline veins to the tubular heart of the embryo. This constitutes the vitelline circulation, and by means of it nutritive material is absorbed from the yolk-sac and conveyed to the embryo.