Question

What are fetal membranes? Give their names. Mention the function of each membrane.

Answer 1

Mainly in unborn humans more than eight weeks after conception is known as a fetus and lies in the amniotic sac. Before eight weeks the unborn is known as an embryo. During development, the embryo grows inside and has four extraembryonic membranes that protect and nurture it.

Complete step-by-step answer:
Membrane-associated with the developing fetus is known as the fetal membranes. These membranes are the yolk sac, the allantois, the amnion, and the chorion. The two chorioamnionitis membranes are given below and they mainly act as a barrier, signaling of fetal maturation and parturition.
Amnion: It makes up the tough amniotic sac that surrounds and protects the embryo. It is a transparent membrane which lines the chorion and is made up of mesoderm and ectoderm. The amnion is one of the defenses against any damage to the fetal during the developmental stages as injuries or any kind of harm can lead to fetal death. The amnion also ensures the structural integrity of the sac due to its mechanical strength. The fully formed offspring is ready to come out of the womb is determined by the rupture of the amnion membrane. It is also present in the embryos of reptiles and birds but is not present in amphibians and fish offspring.
Chorion: is the outer membrane and is in contact with the uterine wall. It is involved in placental formation. It protects and nurtures the embryo. It is made of trophoblast and the mesoderm. The chorion grows chorionic villi which act as a barrier between maternal blood and fetal blood and absorbs maternal blood for the embryo’s necessities. The chorion produces a fluid known as chorionic fluid this protects the embryo by absorbing shock originating from forces such as movement.
Yolk sac: provides nutrition and gas exchange between the mother and the developing embryo before the placenta is formed.
Allantois: collects liquid waste from the embryo and also exchanges gases used by the embryo.

Note: The allantois and yolk sac together form the umbilical cord which provides a connection through which food reaches the fetus, and wastes are removed. These membranes and chorion membrane make up the placenta, this physically attaches the embryo to the uterine wall of its mother.