Final answer:
The collective term for the embryo or fetus, placenta, and membranes is 'products of conception'. Key structures like the chorion, amnion, and yolk sac play crucial roles in the development and protection of the embryo, with the chorion forming an essential part of the fetal placenta.
Step-by-step explanation:
Products of Conception
The products of conception, including the embryo or fetus, the placenta, and membranes, are collectively known as the 'products of conception' or sometimes referred to more specifically as the gestational structures. The chorion is an important fetal membrane that develops into the fetal portion of the placenta, providing an interface for nutrient, waste, and gas exchange between the pregnant person and the developing offspring. The embryonic development begins with a zygote, which then forms a morula, and later becomes a blastocyst. The blastocyst eventually implants in the uterine wall and is enveloped by the endometrium. The inner cell mass within the blastocyst is destined to become the embryo, while the trophoblasts develop into the chorionic sac, eventually contributing to the formation of the placenta.
During early embryonic development, alongside the chorion, extra-embryonic membranes form to support the embryo, including the amnion, yolk sac, and allantois. The amniotic cavity, surrounded by the amnion, serves as a safeguarding sac around the developing embryo. The yolk sac provides early nourishment and the chorion actively participates in forming the placenta, with finger-like chorionic villi that extend into and interact with the maternal tissues.