The pulmonary circuit is commonly bypassed in fetal circulation. This is because fresh blood is provided by the mother to the fetus.
It is bypassed because there is no need for the blood to go to the lungs and get "pick up" if the pig is dead.
Because the fetal lungs are inactive, the pulmonary circuit is bypassed. Half of the blood that enters the right atrium flows directly into the left atrium through the foramen ovale. The remainder flows from the right atrium to the right ventricle, then into the pulmonary trunk. The second bypass, the ductus arteriosus, transports the blood directly from the pulmonary artery into the aorta so it can be sent into systemic circulation.
In fetal circulation, the ductus arteriosus is a connective vessel between the pulmonary artery and aorta. It works as to bypass the lungs, which are collapsed in the womb. After birth, the ductus arteriosus normally closes.
ductus arteriosum
The ductus arteriosus and foramen ovale are important for systemic circulation. This is the type of circulation maintained by fetal pigs but the adult heart requires pulmonary and systemic circulation.
In fetal circulation, the placenta provides oxygen and nutrients to the fetus, so the lungs are not used for oxygen exchange - instead, a bypass called the ductus arteriosus shunts blood away from the lungs. After birth, the lungs take over oxygen exchange, the ductus arteriosus closes, and the foramen ovale between the atria closes, redirecting blood flow through the heart to support pulmonary circulation.
The ductus arteriosus and foramen ovale are important for systemic circulation. This is the type of circulation maintained by fetal pigs but the adult heart requires pulmonary and systemic circulation.
Ductus arteriosus
The pulmonary circuit is to exchange respiratory gases between the blood and inhaled air. As a fetus is not yet breathing on its own but receives its oxygen from the mother through the umbilical vein it surpasses the normal function of the pulmonary circuit and is not necessary.
The lungs are the major organ system bypassed in fetal circulation, as the fetus receives oxygen and nutrients from the mother through the placenta instead of through respiration. Once born, the ductus arteriosus and foramen ovale close, redirecting blood flow to the lungs for oxygenation.
There are two veins that carry oxygen they are the Pulmonary vein and the Umbilical vein:-)
The opening between the right and left atrium is the foramen ovale. The duct connecting the pulmonary artery to the aorta is the ductus arteriosus.