The Ductus Arteriosus

Question

The ductus arteriosus
A) is a branch of the basilar artery that helps form the circle of Willis.
B) shunts blood from the umbilical vein to the inferior vena cava, thereby bypassing the fetal liver.
C) shunts blood from the descending aorta to the pulmonary artery.
D) diverts blood away from the fetal lungs.

Accepted Answer

The ductus arteriosus is a fetal blood vessel that connects the pulmonary artery to the aorta, bypassing the non-functioning fetal lungs. This allows oxygenated blood from the placenta to bypass the lungs and flow to the rest of the fetal body. After birth, the ductus arteriosus usually closes within the first few days of life, and the blood flow to the lungs increases.