Placenta

The placenta is the interface at which the exchange of materials occurs between the mother and fetus. The total area of the placental barrier is 4 to 14 sq.m which is almost equal to the total area of the intestinal absorptive surface. It receives about 25ml of oxygen per minute , which if interrupted for even a short interval is fatal for the fetus. IgG, an antibody, can pass through the placenta. The placenta also secretes some important hormones.The placenta has 2 surfaces-a fetal surface and a maternal surface. From the fetal surface is seen arising the umbilical cord. The maternal surface possesses many cotyledons. The placenta has many villi in cross sectional microscopic view-primary, secondary and tertiary villi. When pregnancy comes towards its end, many changes take place in the placenta which decrease the exchange of materials between mother and fetus.