What structure develops from the placenta during pregnancy?

The chorion is the outermost layer of the fetal membranes and is a crucial structure that develops from the placenta during pregnancy. It plays a vital role in the formation of the placenta and participates in the exchange of nutrients, gases, and waste products between the mother and the developing fetus.

The chorion is characterized by its chorionic villi, which extend into the uterine lining and increase the surface area for exchange with maternal blood. This structure not only helps anchor the placenta to the uterine wall but is also involved in the production of hormones necessary to support the pregnancy.

The amnion is another membrane surrounding the fetus, but it primarily forms a protective bag filled with amniotic fluid, which cushions the fetus rather than originating from the placenta itself. The umbilical cord contains blood vessels that connect the fetus to the placenta, but it is not a direct product of the placental tissue. Finally, the decidua refers to the endometrial lining of the uterus during pregnancy, which undergoes changes to support implantation and placental development, but it does not develop from the placenta.