What is on the other side of the umbilical cord?

[EmAnJ]

I've often wondered this (at times while I'm laying in bed trying to sleep, and contemplating life in general) and have yet to find an answer.

The placenta and umbilical cord is a two-way street between mother and baby, giving nourishment and taking waste. Once the umbilical cord passes what will eventually be the belly button, what is on the inside of the fetus? Is the mothers blood just absorbed by the internal organs or is there actually something on the inside of the fetus that feeds it into the heart and/or other significant arteries?

And once the cord is cut, what happens to that section that was on the inside? Does it die and get absorbed by the body? Is it the withered and seemingly useless appendix?

Yes, the mysteries of life (to my un-medically-educated self) that I seek answers too.

Thanks.

[AWB]

IIRC, when the first breath of air hits the lungs, they act like glands and secrete a hormone that almost instantly makes all the fetal blood vessels atrophy. Besides the inner connection of the umbilical, vessels around the heart and lungs (which are quite different than outsiders') also reroute in response to the hormone, setting up the arrangement that borne humans have.

[EmAnJ]

Interesting, thanks. Do you happen to have any links or references?

[Antigen]

This website has a diagram and good explanation of the situation before and after birth.

[Fear Itself]

Here is an illustrated explanation of the umbilical vein and the way it is connected from the placenta to the blood system of the fetus.

[EmAnJ]

Fantastic! Thank you so much!

[Colibri]

Originally Posted by EmAnJ

Is the mothers blood just absorbed by the internal organs or is there actually something on the inside of the fetus that feeds it into the heart and/or other significant arteries?

It should be noted, in case the diagrams don't make this clear, that the circulatory systems of the mother and fetus remain completely separate. The two systems approach each other very closely within the placenta, but the blood does not mix (with the occasional exception of small ruptures between vessels). The mother's blood does not enter the fetus itself at all. Nutrients, gases, and waste material are transferred between the two systems within the placenta.