What Is Fetal Circulation?
Arterial blood saturated with oxygen in the placenta passes through the umbilical vein, one to the liver and the portal vein anastomosis through the hepatic vein to the inferior vena cava, and one directly into the inferior vena cava via a venous catheter. The inferior vena cava containing mixed blood is injected into the left atrium from the right atrium 1/3 to 1/2 through the oval hole, and the blood from the superior vena cava almost completely enters the right ventricle from the right atrium, and the blood from the right ventricle flows into the pulmonary artery. Only a small amount flows to the lungs, most of which enter the descending aorta through the arterial catheter and flow to the whole body. Part of the blood from the descending aorta goes to the lower body and viscera and enters the right atrium through the inferior vena cava. The rest of the blood passes through the inferior vena cava to the umbilical artery and returns to the placenta. After oxygenation, the blood flows through the inferior vena cava to the right atrium. It can be seen that the left and right hearts of the fetus send blood to the whole body, which is equivalent to only systemic circulation and no pulmonary circulation.
- Chinese name
- Fetal blood circulation
- Foreign name
- fetal circulation
- Arterial blood saturated with oxygen in the placenta passes through the umbilical vein, one to the liver and the portal vein anastomosis through the hepatic vein to the inferior vena cava, and one directly into the inferior vena cava via a venous catheter. The inferior vena cava containing mixed blood is injected into the left atrium from the right atrium 1/3 to 1/2 through the oval hole, and the blood from the superior vena cava almost completely enters the right ventricle from the right atrium, and the blood from the right ventricle flows into the pulmonary artery. Only a small amount flows to the lungs, most of which enter the descending aorta through the arterial catheter and flow to the whole body. Part of the blood from the descending aorta goes to the lower body and viscera and enters the right atrium through the inferior vena cava. The rest of the blood passes through the inferior vena cava to the umbilical artery and returns to the placenta. After oxygenation, the blood flows through the inferior vena cava to the right atrium. It can be seen that the left and right hearts of the fetus send blood to the whole body, which is equivalent to only systemic circulation and no pulmonary circulation.
Fetal blood circulation The circulation of blood in the fetus and its characteristics:
- Fetal nutrition and gas metabolism are exchanged with the mother through the umbilical vessels and placenta. Arterial blood from the umbilical disc enters the fetus through the umbilical vein and divides into two branches at the lower edge of the liver; one enters the liver and matches the portal vein, and then flows from the hepatic vein into the inferior vena cava; Mixed with venous blood from the lower body and into the right atrium. Most of the blood in the right atrium does not flow to the right ventricle, enters the left atrium through the oval hole, and then enters the aorta through the left ventricle, supplying the heart, brain, and upper limbs. Most of the blood from the superior vena cava from the upper body flows into the right atrium and flows into the right ventricle before turning to the pulmonary artery. Because the fetal lung is in a compressed state, most of the blood in the pulmonary artery enters the descending aorta through the arterial catheter and mixes with the aortic blood to supply the abdominal organs, trunk and lower limbs. At the same time, it returns to the placenta through the umbilical artery for nutrition and oxygen, and then through the umbilical vein To the fetus. Features of fetal blood circulation; (1) fetal nutrition and gas exchange are completed through the placenta and umbilical blood vessels; (2) only systemic circulation, almost no pulmonary circulation; (3) most of the fetal body is mixed blood; (4) veins Catheters, oval holes, and arterial catheters are special pathways for fetal blood circulation; (5) The blood oxygen content of the liver is highest during the fetal period, followed by the heart, brain, and upper limbs, and the lower body is the lowest. After the fetus is born, the umbilical cord is ligated and cut off, and the umbilical blood flow is stopped and discarded. The umbilical vein becomes a hepatic round ligament, the umbilical artery becomes a umbilical ligament, lung breathing is established, and gas exchange begins. One cycle becomes two cycles. Systemic and pulmonary circulation. The oval hole was closed, and the two-hearted room stopped traffic. Arterial catheters become arterial ligaments. If the arterial catheter is not closed after 1 year of age, it can be considered that there is a deformity.
Fetal blood circulation blood circulation process:
- The blood circulation process of fetal material exchange with mother through placenta:
- Blood circulation during which the fetus exchanges material with the mother through the placenta. Arterial blood from the placenta enters the fetus through the umbilical vein, and is mixed with venous blood from the portal vein through the sinusoid of the liver (both blood from cattle and dogs is passed through the venous catheter to the posterior vena cava) and then assembled into several hepatic veins. After entering the vena cava, it is mixed with venous blood from the back half of the body and injected into the right atrium. Most of the blood flows into the left atrium through the oval hole in the atrial septum, and then through the left ventricle to the aorta and its branches, and most of the blood goes to the head and forelimbs. Venous blood from the anterior half of the fetus's body enters the right atrium through the anterior vena cava and then into the pulmonary artery through the right ventricle. Because the fetus's lungs have no functional activity, most of the blood in the pulmonary artery flows through the arterial catheter to the aorta, mainly to the rear half of the body, and then returns to the mother's placenta through the umbilical artery. Most of the blood in the fetal blood circulation is mixed, but the degree of mixing is different. The blood to the liver, head and neck, and forelimbs contains more oxygen and nutrients, while the blood to the lungs, trunk, and hind limbs contains less oxygen and nutrients. This is an activity that adapts to the liver function of the fetus and requires faster head development.
- After the fetus is born, the blood circulation changes due to the interruption of the placental circulation and the lungs begin to breathe. The first is umbilical arterial and venous atrophy and atresia. The umbilical artery gradually becomes the bladder circular ligament, and the umbilical vein becomes the hepatic circular ligament. Due to the start of pulmonary functional activities, all the blood in the pulmonary arteries reached the lungs, and then passed through the arterial catheter to the aorta, causing the arterial catheter to become an arterial catheter cord. Because all the pulmonary vein blood flows back to the left atrium, the room is filled with blood, the internal pressure is increased, the oval foramen valve is connected to the atrial septum, and the oval foramen is blocked, causing the heart to completely separate from the left and right, and transformed into adult blood circulation.