extraembrionário
The term *extraembrionário* refers to structures and tissues that develop outside the embryo itself during early vertebrate embryogenesis, playing crucial roles in nourishment, protection, and support until the fetus becomes fully independent. These structures are essential for the proper development of the embryo within the mother’s uterus, particularly in mammals, though similar formations exist in other vertebrates.
The most prominent extraembrionário structures include the **chorion**, **amnion**, **yolk sac**, and **allantois**. The **chorion** is
In humans and other placental mammals, the placenta itself is an extraembrionário organ formed by the fusion
The study of extraembrionário structures is fundamental in developmental biology, offering insights into evolutionary adaptations, reproductive