Why the mass of placenta increases as foetus develops?

As the foetus develops, the placenta also increases in mass. This is because the placenta is responsible for providing the foetus with oxygen and nutrients, and removing waste products. As the foetus grows, it requires more oxygen and nutrients, and produces more waste products. The placenta must therefore increase in size and mass in order to meet the demands of the developing foetus.

Here are some of the specific reasons why the placenta increases in mass as the foetus develops:

* Increased blood flow: The placenta is supplied with blood from the mother's uterine arteries. As the foetus grows, the blood flow to the placenta increases in order to meet the foetus's increasing oxygen and nutrient requirements. This increased blood flow causes the placenta to swell and increase in mass.

* Increased surface area: The placenta is made up of a network of blood vessels that are surrounded by chorionic villi. Chorionic villi are small, finger-like projections that extend from the placenta into the mother's uterine wall. As the foetus grows, the chorionic villi increase in number and size, which increases the surface area of the placenta. This increased surface area allows for more efficient exchange of oxygen and nutrients between the mother and the foetus.

* Increased thickness: The placenta also increases in thickness as the foetus develops. This is because the chorionic villi become longer and thicker, and the blood vessels within the placenta become more dilated. The increased thickness of the placenta helps to ensure that the foetus receives an adequate supply of oxygen and nutrients.

The placenta is a vital organ for the developing foetus. It provides the foetus with oxygen and nutrients, removes waste products, and produces hormones that are essential for pregnancy. The placenta increases in mass as the foetus develops in order to meet the increasing demands of the growing foetus.