Achiever Test #1 bio 22

[osimsDDS]

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The following membranes develop into the placenta and umbilical cord except for one. What is that one exception?

a) Vitelline membrane
b) yolk sac
c) amnion
d) chorion
e) allantois

I know the answer is A because vitelline membrane is derived of the egg and the zona pelucida of the egg, BUT yolk sac doesnt make sense either, in humans the yolk sac doesnt do anything...its just an unfilled sac. the other 3 are obvious but yolk sac I dont believe developes into placenta or umbilical cord...what do you guys think...thanks

 

[mddang]

I remember reading that the yolk sac is associated with the umbilical cord somewhere before.


Confirmed by Wiki!


http://en.wikipedia.org/wiki/Umbilical_cord
Development and composition

The umbilical cord develops from and contains remnants of the yolk sac and allantois (and is therefore derived from the same zygote as the fetus).

 

[drgreen]

yup, the yolk is involved in umbilical cord formation. At around 30 days, the yolk sac pinches into a vitelline duct, which is surrounded by a primitive umbilical ring containing arteries and veins.

 

[klutzy1987]

I got this one wrong, Cliffs doesnt say anything about the yolk sac turning into the unbilical. Just says about the chorion and amnion forming the placenta and the allantois forming the umbilical cord

 

[osimsDDS]

I got this one wrong, Cliffs doesnt say anything about the yolk sac turning into the unbilical. Just says about the chorion and amnion forming the placenta and the allantois forming the umbilical cord

haha yea klutzy thats why i was confused because im using cliff's also...

 

[rippinitez]

Im pretty sure it's somehow related to the umbilical vessels. I think I remember that from Kaplan.