The Reproductive System Of The Fetus Essay

732 Words Nov 24th, 2015 3 Pages
During pregnancy the cardiorespiratory system of the fetus adapts for survival in utero and then changes to an independent postnatal circulatory system. In order to understand the differences in fetal circulation versus postnatal circulation it is important to note that in a fully functioning not pregnant mammal blood circulates in the following way: vena cava, right atrium, tricuspid valve, right ventricle, pulmonary semi lunar valve, pulmonary arteries, lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta, systemic circulation, vena cava. Fetal circulation works by using three shunts to direct deoxygenated blood and avoid the not yet fully developed lungs and liver. The patent foramen ovale directs highly oxygenated blood from the right atrium to the left atrium so that the lungs are passed by. The second shunt the ductus arteriosus protects the lungs against circulatory overload and allows the right ventricle to strengthen. The last shunt, the ductus venosus is a fetal blood vessel connecting the umbilical vein to the inferior vena cava. The ductus venosus carries mostly oxygenated blood and is regulated via a sphincter. . In addition, the placenta connects to the fetus via an umbilical cord, which is made up of the umbilical vein and the two umbilical arteries. Thus, there are several anatomical differences in utero versus postnatal. The differences account for the large difference in fetal circulation. Fetal circulation…

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