Fetal circulation
In the fetus, the lungs are collapsed and fluid-filled. Therefore, there is high resistance to blood flow. The placenta will act as a fetal lung and it provides oxygen for the fetus, delivers nutrients and removes wastes. The fetus is connected to the placenta by the umbilical cord. The oxygenated blood comes from placenta to the fetus through umbilical vein to the fetus’s liver. Then it moves through ductus venosus. This allows some of the blood to go to the liver. But most of this highly oxygenated blood flow to the inferior vena cava and then into the right atrium of the heart. Most of the blood flow across to the left atrium through the foramen ovale. Then blood moves down into the left ventricle. It is then pumped into the ascending aorta. From the aorta, the oxygen-rich blood is sent to the brain, to the heart muscle, and to the lower body. Blood returning to the heart from the fetal body contains carbon dioxide and waste products as it enters the right atrium. It flows down into the right ventricle. Then it bypasses the lungs and flows through the ductus arteriosus into the descending aorta. Descending aorta connects to the umbilical arteries and from there, blood flows back into the placenta.
Congenital heart disease
Congenital heart disease is the most common types of defect which is present at birth. It affects up to 9 in every
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It affects premature infants because their lungs not fully develop and the lungs don’t have an insufficient surfactant. The surfactant is a complex phospholipid+ protein secreted by type 2 cell. It reduces surface the tension of alveolus. It keeps the alveoli open and prevents a collapse of the alveoli. When the surfactant is inadequate the alveoli will collapse, lung expansion will become more difficult ( compliance). Therefore, the infants can’t be able to breath enough amount of oxygen and this may affect the infant’s