Allantois vs. Placenta

[bamtori]

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From Kaplan diagnostic test:

Which of the following is involved in respiration and excretion and develops into the placenta in humans?
A. Chorion <-- I chose this answer (develops into placenta)
B. Allantois <-- this is the answer they gave
C. Amnion
D. Yolk sac
E. Placenta

Another poorly worded problem? I understand that excretion is handled mainly by the allantois, but chorion + endometrium = placenta.

 

[tooth knockn]

Are these questions on the dat?

 

[bamtori]

Are these questions on the dat?

I don't really know what you're asking. This question is from the Kaplan diagnostic exam. Worry less about which topics will show up on the exam, instead try to cover as much ground as you can, especially for bio, so that you can compile everything you know about the question at hand to formulate an answer.

 

[tooth knockn]

Ok, sorry.

 

[emminent]

From Kaplan diagnostic test:

Which of the following is involved in respiration and excretion and develops into the placenta in humans?
A. Chorion <-- I chose this answer (develops into placenta)
B. Allantois <-- this is the answer they gave
C. Amnion
D. Yolk sac
E. Placenta

Another poorly worded problem? I understand that excretion is handled mainly by the allantois, but chorion + endometrium = placenta.

Hey dude so here's from cliffs.

The chorion is the outer membrane. In birds and reptiles it acts as a membrane for gas exchange. In mammals, the chorion implants into the endometrium. Later, the chorion, together with maternal tissue, forms the placenta.The placenta is a blend of maternal and embryonic tissues across which gases, nutrients, and wastes are exchanged.

The allantois begins as a sac that buds off from the archenteron. Eventually, it encircles the embryo, forming a layer below the chorion. In birds and reptiles, it initially stores waste products (in the form of uric acid). Later in development, it fuses with the chorion, and together they act as a membrane for gas exchange with blood vessels below. In mammals, the allantois transports waste products to the placenta. After subsequent development, it forms the umbilical cord, transporting gases, nutrients, and wastes between the embryo and the placenta.

Even though it said it is for reptiles and birds and didn't mention much about mammals, chorion is mostly gas exchange. On the other hand, allantois, from the definition, encompasses more of the respiration and excretion portion.

But yeah I kinda think it's poorly worded.