How is the circulation of a fetus different from the circulation of a baby answers?

Without getting to wordy, I'll try to explain it simply on the differences between fetal circulation and newborn circulation.

In utero, the baby has an umbilical cord. All nutrients and exchanges are done by this. Because the baby cannot physically breathe air for oxygen exchange two shunts are used to by pass the lungs for oxygenation. Those two shunts are called the foramen ovale and the ductus arteriosus.

So, here are the steps of fetal circulation:

1. Mom passes oxygenated blood to the fetus through the placenta. Through the placenta it is carried through the umbilical cord to the liver and then there is a branch of 3.

2. At the branch in the liver, the oxygenated blood goes into the inferior and superior vena cava into the right atrium of the heart. This is where the foramen ovale comes in. The blood from the right atrium goes through the foramen ovale and directly into the left atrium.

3. After in the left atrium, it will pass into the aorta and through the body and will return.

In a newborn:

Once the umbilical is clamped off, this initiates the ductus arteriosus to snap close and build pressure in the left atrium and ventricle. Once the pressure has shifted from the right to the left, the foramen ovale will snap closed, as well. Then, the newborn will resume normal body circulation meaning the lungs will do the work.

The deoxygenated blood will enter through the vena cava, to the right atrium, to the left atrium, through the pulmonary artery and into the lungs. The lungs will do oxygen/co2 exchange and will send oxygenated blood back through the pulmonary vein. From the pulmonary vein it will go into the left atrium, to the left ventricle and out through the aorta and to the entire body.

I hope I was able to explain it to you well.