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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 ...
The endocardial cushions are thought to arise from a subset of endothelial cells that undergo epithelial-mesenchymal transition, a process whereby these cells break cell-to-cell contacts and migrate into the cardiac jelly (towards the interior of the heart tube).
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.
Persistent fetal circulation is a condition caused by a failure in the systemic circulation and pulmonary circulation to convert from the antenatal circulation pattern to the "normal" pattern. Infants experience a high mean arterial pulmonary artery pressure and a high afterload at the right ventricle.
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.
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]
Histopathology of placenta with increased syncytial knotting of chorionic villi, with two knots pointed out. The following characteristics of placentas have been said to be associated with placental insufficiency, however all of them occur in normal healthy placentas and full term healthy births, so none of them can be used to accurately diagnose placental insufficiency: [citation needed]
Vitelline circulation refers to the system of blood flowing from the embryo to the yolk sac and back again. The yolk-sac is situated on the ventral aspect of the embryo; it is lined by endoderm , outside of which is a layer of mesoderm .