WHAT IS THE PLACENTA?
The human placenta is the lifeline between baby and mother. This temporary organ begins forming not long after conception and is expelled from the mother's body immediately after the baby is born. However, in this short time it provides nutrients and oxygen for the baby, removes waste products from the baby's system, manufactures and releases hormones, provides protection for the baby against disease and immune attacks, and many other important functions. The placenta is dedicated to the survival of the baby, even to the extent of putting the mother at risk in some cases.
The placenta is derived from both fetal and maternal cells. The placenta first takes shape when cells from the fetus, called trophoblasts, attach to the uterus wall and then proceed to invade the tissues of the uterus. They eventually reach deep into the wall and connect with the mother's blood vessels. As the placenta continues to develop, a network is formed of finger-like projections, called villi, which project into spaces, or lacunae, that fill up with the mother's blood. At this time the baby's circulatory system is developing, and fetal blood vessels form in the placental villi. These vessels connect back to the baby via blood vessels traveling through the umbilical cord, which attaches the baby to the placenta. Gas and nutrient exchange and waste removal take place across the villis' walls, which also serve to keep the baby's blood from mixing with the mother's blood.

Continue reading about the placenta...