Which statement correctly contrasts the foramen ovale and the ductus arteriosus in fetal circulation?

Which statement correctly contrasts the foramen ovale and the ductus arteriosus in fetal circulation?

• A. Foramen ovale connects right and left atria, while ductus arteriosus connects pulmonary artery to aorta
• B. Foramen ovale is a valve; ductus arteriosus is a vessel
• C. Foramen ovale connects ventricles, while ductus arteriosus connects atria
• D. Foramen ovale connects pulmonary artery to aorta, while ductus arteriosus connects right atrium to left atrium

Answer: (A)

In fetal circulation, the lungs aren’t used for oxygenation, so blood is redirected away from them by two shunts. The foramen ovale is an opening in the wall between the right and left atria that allows blood to pass from the right atrium into the left atrium, bypassing the right ventricle and the developing lungs. The ductus arteriosus is a vessel that connects the pulmonary artery to the aorta, routing blood away from the lungs into the systemic circulation. This statement is correct because it accurately describes those connections: the foramen ovale links the atria, and the ductus arteriosus links the pulmonary artery to the aorta. The other options misstate these connections or mischaracterize the structures (foramen ovale is not a valve, and it does not connect ventricles; the wrong vessels are described in some choices). After birth, these shunts close as pressures shift and the lungs take over oxygenation.

In fetal circulation, the lungs aren’t used for oxygenation, so blood is redirected away from them by two shunts. The foramen ovale is an opening in the wall between the right and left atria that allows blood to pass from the right atrium into the left atrium, bypassing the right ventricle and the developing lungs. The ductus arteriosus is a vessel that connects the pulmonary artery to the aorta, routing blood away from the lungs into the systemic circulation.

This statement is correct because it accurately describes those connections: the foramen ovale links the atria, and the ductus arteriosus links the pulmonary artery to the aorta. The other options misstate these connections or mischaracterize the structures (foramen ovale is not a valve, and it does not connect ventricles; the wrong vessels are described in some choices). After birth, these shunts close as pressures shift and the lungs take over oxygenation.