Foetal Circulation - Anatomy & Physiology
Foetal versus Adult Circulation
A large number of physiological processes that are necessary for the embryo’s survival, such as detoxification, gas exchange and waste removal, are carried out by the placenta [[1]] rendering organs such as the liver and lungs surplus to requirement. There are a number of foetal circulatory shunts that ensure oxygen and nutrient rich blood flows directly to the most important organs, namely the brain, heart and adrenal glands.
Shunt 1: The Ductus Venosus
Oxygenated blood travels from the placenta via the umbilical vein and most of it bypasses the liver by way of the ductus venosus. The ductus venosus links the umbilical vein to the caudal vena cava and the flow of blood is controlled by a sphincter, enabling the proportion travelling to the heart versus the liver to be altered.