Essay On Fetal Circulation

681 Words2 Pages

The transition from fetal to neonatal circulation is a complex process that has important clinical consequences if it does not occur correctly. Understanding the anatomy of fetal circulation and how this anatomy changes during the transitional period is important for understanding many neonatal and pediatric diagnoses.
In the fetal circulation, the right and left ventricles work in a parallel circuit. The ductus venosus, foramen ovale, and ductus arteriosus are three cardiovascular structures that are important for maintaining this circulation. The umbilical vein carries relatively well-oxygenated blood from the placenta to the IVC through the ductus venosus, where it partially mixes with poorly oxygenated IVC blood from the lower part of the fetal body. When it reaches the right atrium, oxygenated blood is preferentially shunted across the foramen ovale and then enters the left atrium, where it mixes with blood from the pulmonary veins before entering the left ventricle. From the LV, the ascending aorta sends fully oxygenated blood to the coronary arteries, the head, and the upper extremities. Only a small portion of the LV cardiac output streams through the aortic arch and supplies flow to the thoracic aorta. …show more content…

Only about 10% of RV output enters the pulmonary arteries because the fetal lungs are still not expanded and ventilated, which causes pulmonary vascular resistance to be very high. Most RV output flows through the ductus arteriosus, bypassing the lungs, and into the descending aorta and the inferior part of the fetal body, after which it returns to the placenta via the two umbilical arteries. The placenta is a low-resistance vascular bed where oxygenation and metabolite exchange occur. The now oxygenated blood then re-enters the umbilical

More about Essay On Fetal Circulation

Open Document