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In humans, the circulatory system is different before and after birth. 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 ...
It is one of two fetal cardiac shunts, the other being the ductus arteriosus (which allows blood that still escapes to the right ventricle to bypass the pulmonary circulation). Another similar adaptation in the fetus is the ductus venosus. In most individuals, the foramen ovale closes at birth. It later forms the fossa ovalis.
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.
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.
The major changes that are made by the body occur at the first breath (in the case of heart and lung functions) and up to weeks after birth (such as the liver's enzyme synthesis). The foramen ovale becomes the fossa ovalis as the foramen closes while edge of the septum secundum in right atrium becomes the anulus ovalis, so the depression ...
A catheter may be inserted into one of the umbilical arteries of critically ill babies for drawing blood for testing. [6] This is a common procedure in neonatal intensive care, and can often be performed until 2 weeks after birth (when the arteries start to decay too much). [7]
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The "E" series of prostaglandins are responsible for maintaining the openness of the ductus arteriosus (by dilation of vascular smooth muscle) throughout the fetal period. [3] Prostaglandin E2 (PGE 2 ), produced by both the placenta and the DA itself, is the most potent of the E prostaglandins, but prostaglandin E1 (PGE 1 ) also has a role in ...