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The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage resulting in the presence of shunts to move oxygenated blood and ...
As the fetal lungs are non-functional at this time, the blood bypasses them through two cardiac shunts. The first is the foramen ovale (the valve present between them called eustachian valve) which shunts blood from the right atrium to the left atrium. The second is the ductus arteriosus which shunts blood from the pulmonary artery (which ...
Diagram of the human fetal circulatory system. The heart and blood vessels of the circulatory system form relatively early during embryonic development, but continue to grow and develop in complexity in the growing fetus. A functional circulatory system is a biological necessity since mammalian tissues can not grow more than a few cell layers ...
Ductus arteriosus evolved with the lung in the ancestors of the lungfish as a connection between the pulmonary arteries and dorsal aorta. During embryonic development, reptiles, birds, and mammals all have either one or two paired ductus arteriosi that provide a fetal shunt of blood away from the lungs. [10]
Before birth, the fetal circulation directs oxygen-rich blood returning from the placenta to mix with blood from the hepatic veins in the inferior vena cava. Streaming this blood across the atrial septum via the foramen ovale increases the oxygen content of blood in the left atrium.
The vitelline arteries are the arterial counterpart to the vitelline veins. Like the veins, they play an important role in the vitelline circulation of blood to and from the yolk sac of a fetus. They are a branch of the dorsal aorta. They give rise to the celiac artery, superior mesenteric artery, and inferior mesenteric artery. [1]
The sinus venosus connects to the fetal circulation. The heart tube elongates on the right side, looping and becoming the first visual sign of left-right asymmetry of the body. Septa form within the atria and ventricles to separate the left and right sides of the heart. [3]
The interatrial septum is a septum that lies between the left atrium and right atrium of the human heart.The interatrial septum lies at angle of 65 degrees from right posterior to left anterior because right atrium is located at the right side of the body while left atrium is located at the left side of the body. [1]