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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 ...
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]
The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the chorionic villi.More than two-thirds of fetal hepatic circulation is via the main portal vein, while the remainder is shunted from the left portal vein via the ductus venosus to the inferior vena cava, eventually being delivered to the fetal right atrium.
A study of 32 normal pregnancies showed that fetal heart motion was visible at a mean human chorionic gonadotropin (hCG) level of 10,000 UI/L (range 8650–12,200). [19] Obstetric ultrasonography can also use Doppler technique on key vessels such as the umbilical artery to detect abnormal flow. Doppler fetal monitor
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, after birth, carries blood from the right side of the heart to the lungs) to the descending aorta.
A VSD can cause a left-to-right shunt of blood flow in the heart and is one of the most common of the congenital heart defects. This type of shunt is an acyanotic disorder that can result in ventricular hypertrophy. [4] The alignment of interventricular septum and interatrial septum is disturbed in various congenital heart diseases. [5]
The pathway of fetal umbilical venous flow is umbilical vein left portal vein ductus venosus inferior vena cava eventually right atrium.. This anatomic course is important to recall when assessing the success of neonatal umbilical venous catheterization, as failure to cannulate through the ductus venosus results in malpositioned hepatic catheterization via the left or right portal veins.
In prenatal development, the eustachian valve helps direct the flow of oxygen-rich blood through the right atrium into the left atrium and away from the right ventricle. . 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