Remember, the doctor's arteriosis connects the pulmonary trunk to our aorter. So what happens as soon as we take the first breath? Well, when we take the first breath, we have more blood flowing into the lungs, and the lungs decrease in pressure. At the same time, we have more blood flowing into the order. So the order increases in pressure. And now we have a high pressure in the order, a low pressure in that pulmonary trunk.