Question

Describe the role of the ductus arteriosus in the foetal cardiovascular system and the reason for it's normal functional closure in the immediate neonatal period.

Answer 1

Ductus arteriosus acts as a shunt between the pulmonary artery and the aorta in the growing fetus. It inhibits the blood flow to the lungs for oxygenation which are filled with amniotic fluid insteas oxygenation of blood is carried over in the placenta before being returned to the body. Therefore,immediate closure of ductus arteriosus in the neonatal period is essential for survival and breathing via pulmonary system. It usually occurs by about 15 hours of life in healthy infants born at term. It is aided by abrupt contraction of the muscular wall of the ductus arteriosus resulting in increased the partial pressure of oxygen (PO₂)which coincident with the first breath.