extraembryonic membranes

[nsp716]

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There is a question on one of the kaplan tests that asks "which of the following extraembryonic membranes functions in respiration?" the choices are allantois, chorion, yolk sac, umbilical cord, amnion. (answer: allantois)

Why is allantois a better answer than chorion? I thought the allantois and chorion together function in respiration/gas exchange...and in the chick/reptile, the allantois removes uric acid) The question did not specify whether it was chick, reptile or mammal...

 

[Resonance]

The allantois has blood vessels, which along with removing waste also transports O2 in and CO2 out. I think the chorion is for our purposes just a lining.

 

[RozhonDDS]

diffusion occurs across the capillaries

 

[letsgfuad]

The allantois has blood vessels, which along with removing waste also transports O2 in and CO2 out. I think the chorion is for our purposes just a lining.

Atleast in chick embryos' the chorion is a thin membrane underneath the shell. It has some enzymes used for different processes, one of which is CAM chorion allantois membrane which extracts Calcium Carbonate from the shell for bone growth. I know this because i did an experiment in devel. bio.

 

[nsp716]

Atleast in chick embryos' the chorion is a thin membrane underneath the shell. It has some enzymes used for different processes, one of which is CAM chorion allantois membrane which extracts Calcium Carbonate from the shell for bone growth. I know this because i did an experiment in devel. bio.

What about in humans? I know the chorion becomes the placenta and the allantois becomes the umbilical chord (artery and vein). Doesn't gas exchange occur across the placental capillaries (which merge into the umbilical artery and vein)?

 

[armorshell]

What about in humans? I know the chorion becomes the placenta and the allantois becomes the umbilical chord (artery and vein). Doesn't gas exchange occur across the placental capillaries (which merge into the umbilical artery and vein)?

You made it seem as if the question didn't specifically mention human development...

 

[nsp716]

You made it seem as if the question didn't specifically mention human development...

Oh, it didn't...I was just wondering. If they don't specify in the question on the real DAT (which I figured they would), should I assume they're not referring to human???

 

[armorshell]

Oh, it didn't...I was just wondering. If they don't specify in the question on the real DAT (which I figured they would), should I assume they're not referring to human???

Havn't taken it yet, but I'd assume they'd have to tell you...