1 The bilaminar embryonic disc is attached to the trophoblast by the connecting stalk.
2 Gastrulation converts a bilaminar embryonic disc into a trilaminar embryonic disc.
3 Chorionic villi help to bring the fetal and maternal blood vessels close to each other.
4 The placenta functions in the exchange of materials betweenthe fetus and mother, serves as a protective barrier against many microbes, and stores nutrients.
5 During this time, fetal weight doubles.