The interatrial opening, which results in the interatrial partition remaining functionally incomplete up to the time of birth, is known as which of the following?
A) ductus arteriosus
B) ligamentum arteriosum
C) foramen ovale
D) ductus venosus
E) inferior vena cava

Question

Quizplus · Accepted Answer

The interatrial opening that allows blood to bypass the lungs and enter the left atrium during fetal development is known as the foramen ovale. This opening closes shortly after birth, forming the fossa ovalis. Choice A is incorrect because the ductus arteriosus is a fetal blood vessel that connects the pulmonary artery to the descending aorta to bypass the lungs, but it also closes soon after birth. Choice B is incorrect because the ligamentum arteriosum is the remnant of the ductus arteriosus after it has closed. Choice D is incorrect because the ductus venosus is a fetal blood vessel that connects the umbilical vein to the inferior vena cava, allowing oxygen-rich blood from the placenta to bypass the liver. The ductus venosus also closes after birth. Choice E is incorrect because the inferior vena cava is a large blood vessel that carries deoxygenated blood from the lower half of the body to the right atrium, but it is not directly involved in fetal circulation.

The Interatrial Opening, Which Results in the Interatrial Partition Remaining