After birth, the foramen ovale is closed as a result of
A)increasing pressure in the right atrium.
B)increasing pressure in the left atrium.
C)increased resistance in the pulmonary circuit.
D)decreased blood volume in the pulmonary veins.

Question

Quizplus · Accepted Answer

When a newborn takes its first breath, the lungs become inflated and oxygen-rich blood flows into the left atrium, which increases the pressure in the left atrium. This increased pressure pushes the septum primum against the septum secundum, closing the foramen ovale. Thus, option B is the correct answer.

After Birth, the Foramen Ovale Is Closed as a Result