Chorionic villi are finger-like structures that grow from the chorion (outer layer of the fetal membrane) and extend into pools of maternal blood called lacunae. This allows for the exchange of gases, nutrients, and waste products between the maternal and fetal blood without mixing them.

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In the Placenta

Question 58

Multiple Choice

In the placenta:

A) chorionic villi are bathed in pools of maternal blood.
B) fetal blood and maternal blood mix.
C) all substances in maternal blood that may be harmful to the fetus are prevented from going through.
D) the amnion and the chorion grow into the uterus wall.
E) hormones are absorbed to prevent them from influencing the developing fetus.

Correct Answer: