Placenta (Growth) in Human

Introduction of Placenta:

• The placenta is a flattened, discoidal organ in a pregnant woman's uterus that serves as a temporary link between fetal and maternal circulation.
• It is attached to the uterus wall and baby's umbilical cord. The placenta supplies oxygen, nutrients, hormones, antibodies, and removes carbon dioxide and excretory wastes.
• It is the only organ made from tissues from two individuals: the mother and the fetus.
• Part of the placenta contributed by the fetus is called the fetal placenta, and it is formed by the chorionic villi.
• The other part, which is rich in blood supply, is shared by a part of the uterine wall of the mother and is termed the maternal placenta.
• Thus, the human placenta is called haemochorial.
• The umbilical cord consists of three blood vessels, two small arteries and one large vein.
• The placenta acts as an endocrine tissue, producing hormones like hCG, progesterone, and estrogen.
• Relaxin is secreted by the ovary in the later pregnancy phase. hCG levels increase until the first trimester, then decline.
• By the first trimester, progesterone is produced by the placenta, essential for fetal growth and pregnancy maintenance.

Placenta

Functions of the Placenta: 

The placenta performs several essential functions during pregnancy:  

• Nutrient and Gas Exchange: It enables the transport of oxygen and nutrients from the mother to the foetus while also removing carbon dioxide and waste products from the mother. 

• The placenta generates hormones such as human chorionic gonadotropin (hCG), progesterone, and estrogen to maintain pregnancy and promote foetal growth. 

• Immune Protection: It gives immune protection to the foetus by transmitting maternal antibodies, which serve to shield the foetus from infections. 

• The placenta works as a selective barrier, protecting the foetus from harmful substances while allowing vital molecules to flow through.