The lungs have a high resistance, create a high pressure to flow, and that causes a high pressure to exist in the pulmonary trunk as well as the right ventricle and the right atrium. And so that's exactly why the blood will be shunted away from the lungs, will bypass the lungs and go directly from the right atrium into the left atrium, then into the left ventricle, and then into the order. Now, of course, some amount of that blood will still leak into the right ventricle from the right atrium. And when this happens, the blood goes into the pulmonary trunk. Now, when the blood is inside the pulmonary trunk, it also has a choice in the fetal circulatory system because we have this tiny passageway, this tiny shunt that connects the pulmonary trunk and the order. And this is known as the ductus arteriosis.