The placenta is one of the most fascinating organs in the human body. It acts as a life support system for the developing fetus, and is the only organ in the body that disposes of itself after it’s no longer needed. But what happens inside the placenta, and how does it work?
Did you know that while a baby is in the womb, their lungs aren’t in use? Fetal lungs are filled with fluid, and the blood vessels that run through them are tight. Tight blood vessels make it hard for blood to flow through the developing the lungs, and as a result only a small amount of blood can pass through.
When mum breathes, the oxygen from the air in her lungs is transferred into her bloodstream. The blood vessels in her lungs are relaxed and lots of blood is able to flow through, picking up oxygen along the way. This oxygen rich blood travels through her body and makes its way to the placenta.
The placenta is an organ that develops in the mother’s uterus during pregnancy. It attaches to the wall of the mother’s uterus, and the umbilical cord extends from it, connecting to the baby. It is the baby’s life support system and breathing organ while in the womb.
The placenta allows oxygen and nutrients to move from the mothers blood to the fetus’ blood. However, the two blood circulation systems are kept separate. Small, thin walled structures in the placenta, called ‘villi’, allow this exchange to happen. This system also allows for carbon dioxide and waste to be removed from the fetus. The carbon dioxide and the waste are transferred to the mother, who is able to process and dispose of them for the baby.
The placenta also produces hormones that help the baby grow and protects against infection and certain harmful substances. However, certain bacteria, viruses and harmful substances like alcohol, nicotine and other drugs can traverse the placental barrier between mum and baby.
- About 20 percent (almost 1 pint) of a mothers blood supply passes through the placenta every minute!
- At the end of pregnancy the placenta produces the hormones that signal the body to begin producing milk.
- Identical twins sometimes share a placenta, and other times twins have one placenta each!
- By the time the baby is born, the placenta can weigh up to 3 lbs.