An infant has a patent ductus arteriosus. This anomaly occurs when:

Question

a. The opening between the right and left atria fails to close after birth.
b. The structure that shunts blood from the pulmonary artery to the aorta remains open after birth.
c. The aorta arises from the right ventricle and the pulmonary artery originates from the left ventricle.
d. There is a narrowing of the aorta near the level of the ductus arteriosus.

Answer 1

ANS: B
The ductus arteriosus shunts blood from the pulmonary artery to the aorta, bypassing the lungs during fetal life. The functional closure of the ductus arteriosus usually occurs approximately 15 to 20 hours after birth, with fibrosis of the ductus occurring approximately 3 to 4 weeks after birth. The structure allowing blood to flow from right atrium to left atrium is the foramen ovale. The abnormality of the aorta arising from the right ventricle and the pulmonary artery originating from the left ventricle is known as transposition of the great vessels. Coarctation of the aorta is a narrowing of the aorta.