What are the features of the blood circulation in the fetus?
So the arterial, the blood carrying oxygen to the baby, comes to him directly from the placenta through the umbilical vein. This vein in the umbilical cord, together with 2 umbilical arteries, carries blood to the fetus from the placenta.
Then, in the fetal body, the umbilical vein is divided into 2 branches: the venous (arantzium) duct, which delivers the arterial blood directly to the inferior vena cava, where it is mixed; on the second branch - the mother's blood flows through the portal vein system directly into the fetus's liver, where it is cleaned of toxic substances.
As a result, with placental blood circulation of the fetus, mixed blood from the inferior vena cava enters the right atrium of the baby, and the venous one comes from the upper vein. From the right atrium to the right ventricle receives only a small part of the blood, which goes to the small circle of circulation through the pulmonary trunk. It is she who supplies lung tissue, tk. the lungs in the mother's womb do not function.
What formations are present in the fetal circulatory system?
Having examined the scheme of blood circulation of the fetus, it is necessary to mention the presence in it of some functional formations, which the born baby is normally absent.
So in the septum, located between the atria, there is a hole - an oval window. Through him, mixed blood, passing a small circle, falls immediately into the left atrium, from which it flows into the left ventricle. Then the blood flow goes to the aorta, into a large circle. Thus there is a message of 2 circles of the fetal circulation.
Also in the circulatory system of the fetus, a functional formation is distinguished, such as battles of the duct. He connects the pulmonary trunk to the arch of the aorta, and adds to it a certain portion of mixed blood. In other words, the battalion of the duct, along with the oval window, unloads a small circle of blood circulation, directing blood directly to a large circle.
How does the circulatory system change after birth?
From the moment of the first breath of the child, from his birth, a small circle of blood circulation begins to function. After the birth of a baby is bandaged with the umbilical cord, the system of blood circulation of the fetus and the mother ceases to exist. In this case, the placental circulation is completely suspended and the umbilical vein is empty. This leads to a sharp decrease in the pressure in the cavity of the right atrium and to an increase in the left atrium, as. it is there that blood is sent from a small circle. As a result, because of this pressure difference, the oval window valve slams itself. If this does not happen, then the baby is diagnosed with a congenital malformation, because there is a mixture of venous and arterial blood,
As for the Batalov and Arancian ducts, which existed in the intrauterine circulation of the fetus, they spontaneously, literally by the end of the first month of life, crumbs. As a result, the baby, like an adult, begins to function 2 circles of circulation. However, despite this, the infant still has some features of the circulatory system, which is associated with the functioning of individual organs and systems. Therefore, the cardiovascular system of crumbs, one of the first after birth, is examined by ultrasound.