Question

What is placenta?

Answer 1

The placenta describes an organ which develops at the time of the pregnancy in all mammals. The placenta supplies oxygen and nutrients to the developing foetus in the womb of the mother. The placenta is a temporary organ which makes the connection between the foetus to the mother’s uterine walls, through the umbilical cord.

Complete answer:
The placenta is that passage which unites the fetus to the mother. The placenta helps in the exchange of nutrients and oxygen to the fetus. It is also responsible for eliminating carbon dioxide and waste materials from the fetus. In physical appearance, the placenta looks like a disk-like structure and it generally measures about 22 centimeters (max) in length. The placenta is very rich in blood vessels. It possesses villi that increase the surface area for absorption of nutrients.

Only mammals have this unique feature of presence of placenta during pregnancy. The umbilical cord connects the fetus to the placenta, helping in the transfer of materials. The placenta generally joins at the top, bottom, front or back side around the uterus. In some cases, the placenta may get attached with the lower part of the uterus forming the condition called placenta previa.

Note: Major functions of the placenta
1. To allow nutrients intake, temperature regulation, elimination of metabolic waste, gaseous exchange through the mother's blood, to provide defense to foetus, production of necessary hormones.
2. Nutrients and drug transfer occurs through the placenta and this transfer is facilitated by passive diffusion.