How does the placenta function in fetal development?

The placenta functions as a life-support system for the fetus, providing nutrients, oxygen, and removing waste products.

The placenta is a unique organ that forms during pregnancy, attaching itself to the wall of the uterus. It is connected to the fetus by the umbilical cord, which serves as a conduit for the exchange of nutrients, oxygen, and waste products between the mother and the fetus.

The placenta is composed of numerous tiny projections called villi, which are bathed in the mother's blood. The villi increase the surface area of the placenta, facilitating the efficient exchange of substances. Oxygen and nutrients from the mother's blood diffuse across the placental barrier into the fetal blood, while waste products like carbon dioxide and urea diffuse from the fetal blood into the mother's blood.

The placenta also acts as a barrier, protecting the fetus from most bacteria and viruses. However, it is not completely impervious. Some substances, including certain drugs and alcohol, can cross the placental barrier and potentially harm the fetus.

In addition to its role in nutrient and waste exchange, the placenta also produces hormones that are crucial for maintaining pregnancy. These include human chorionic gonadotropin (hCG), which signals the ovaries to continue producing progesterone, a hormone that prevents the uterus from shedding its lining and causing a miscarriage. The placenta also produces hormones that prepare the mother's body for breastfeeding.

In summary, the placenta plays a vital role in fetal development. It not only provides the fetus with the necessary nutrients and oxygen, but also removes waste products, produces essential hormones, and offers a degree of protection against infections.