The fetal circulation:-
The umbilical vein caring the oxygenated blood ( 80% saturated). from the placenta enters the foetus at the umbilical and and runs along the free margin of the falciform ligament of the liver. In the liver it gives of branches to the left lobe of the liver and receive the deoxygenated from the portal vein. The greater portion of the oxygenated blood mixed with some portal Venous blood short circuits the liver through the Ductus Venous to enter the inferior vena cava and thence to right atrium of the heart. the O2 content of this mixed blood is thus reduced. Although both the Ductus venosus and hepatic portal/ fetal trunk bloods enter the right Atrium thought the IVC, there is little mixing. The Terminal part of the IVC receives blood from the right hepatic vein.
In the right Atrium most of the well oxygenated (75%) ductus venosus blood is preferentially directed into the foramen and ovale by the valve of the inferior vena cava and crista dividends and passage into the left Atrium. Here it is mixed with small amount of Venous blood returning from the lungs through the pulmonary veins. This left atrial blood is passed on thought the material opening into the left ventricle.
- Umbilical vein.
- Ductus venosus, (vein to vein).
- Foramen ovale.
- Ductus arteriosus, (artery to artery).
- Two hypogastric arteries.
Umbilical vein:-
Blood flow in the unborn baby follows this pathway. Oxygen and nutrients from the mother’s blood are transferred across the Placenta to the foetus through the umbilical cord. This encircled blood flow Thought the umbilical vein toward the baby’s liver. There is moves through are shunt called the ductus venosus.
Ductus venosus:-
The ductus venosus is a shunt that allows oxygenated blood in the umbilical vein to bypass the liver and is essential for normal fetal circulation. Blood becomes oxygenated in the Placenta and travels to the right Atrium via umbilical veins thought the ductus venosus then to the inferior vena cava.
Foramen ovale:-
The hole between the top two heart chambers ( right and left atrium) is called a patent foramen ovale ( PFO). This hole allows the oxygen which blood to go from the right Atrium to left Atrium and then to the left ventricle and out the aorta. As a result the blood with the most oxygen gats to the brain.
Ductus arteriosus:-
The ductus arteriosus sends the oxygen poor blood to the organs in the lower half the fetal body. This also allows for the oxygen poor blood to leave the fetus thought the umbilical arteries and get back to the placenta to pick up oxygen.
Two hypogastric arteries:
The majority of this blood flow thought the ductus arteriosus into descending aorta, and perfuses lower extremities and hypogastric arteries. Deoxygenated fetal blood Returns to the placenta via two umbilical arteries. Two thirds of fetal blood volume is within the placenta.
Parts of Circulation system:-
- Heart a muscular organ that pumps blood thought out of body.
- Blood vessels, which include your arteries, veins, and capillary.
- Blood mad up of red and white blood cells, plasma and platelets.
Main function of blood:-
- Transporting oxygen and nutrients to the lungs and tissues.
- Forming blood clots to prevent excess blood loss.
- Regulating body temperature.
- Carring cells and antibodies that fight infection.
- Bringing waste products to the kidney and liver, which filter and clean the blood.
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By GS India Nursing………..!!