And so that means they cannot exchange any of that oxygen for carbon dioxide. And so we need another duct. And this duct is called the ductus arteriosis. So the ductus arteriosis connects the pulmonary trunk directly to our order. And so as that blood fills the pulmonary trunk, some of it actually leaves or most of it leaves this section, the pulmonary artery and enters our aorter. Now, of course, a small amount of that oxygenated and nutrient filled blood will actually leave and enter the left and right pulmonary artery.