And so what happens is blood stops flowing from the trunk and to the order. So eventually, the ductus arteriosis will also constrict and will also diminish in size until it stops functioning. Now, to be more specific, what happens is as soon as the pressure inside the lungs increases and as soon as the oxygen is carried into the lungs, the lungs begin producing a special type of peptide, a special type of protein known as bradycanin. And what brady kina does is it causes the constrictions of blood vessels when there is a high amount of oxygen. So the bradyclin essentially travels into the ductus arteriosis. And because now we have a high oxygen content within that ductus arteriosis, the brady kinan basically causes the constriction of that ductus arteriosis.