Topscore test 3 BIO#15

[intnpredent]

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Okay. This question is little confusing to me..

Embryonic gas exchange in the human fetus occurs across the
a. chorion lining
b. chorionic villi
c. alveoli
d. placenta
e. umbilical cord lining

I chose B because I thought it was the site of gas exchange between fetus and mother. BUT the answer is D... Could someone please clarify?😕
Thank you for your input

 

[Kahr]

I think perhaps you're thinking too specifically/finely, which is fine, as you're pretty much on target with your thinking. Just, try to be more simple and broad, it's usually a safer bet.

I'll quote directly from Campbell biology 9th edition, since I believe that's traditionally the reference (or a reference) for the DAT itself.

...the trophoblast, grows outward and mingles with the endometrium, eventually helping form the placenta. This disk-shaped organ, containing both embryonic and maternal blood vessels, can weigh close to 1 kg. Material diffusing between the maternal and embryonic circulatory systems supplies nutrients, provides immune protection, exchanges respiratory gases, and disposes of metabolic wastes for the embryo. Blood from the embryo travels to the placenta through the arteries of the umbilical cord and returns via the umbilical vein... chapter 46, Animal Reproduction, pg. 1013

...and adjacent endometrial tissue will all contribute to formation of the placenta. This vital organ mediates exchange of nutrients, gases, and nitrogenous wastes between the embryo and the mother... chapter 47, Animal Development, pg. 1031

 

[intnpredent]

Thank you for your explanation and comment!! I will try to think in general view for the next time..

 

[drill-and-fill]

I know this thread is a few months old but...


I thought i read from somewhere that chorionic villi is the site of gas exchange? I understand that Placenta as a whole is the site of gas exchange as per Campbell, but then what exactly is the function of chorionic villi? I was gonn pick placena first but i thought they wanted chorinic villi because its more specific... I hope the actual DAT doesnt have tricky questions like these where more than one choice may be the answer...