So this is what we're going to focus on in this lecture and we're going to discuss several important key factors that inhibit the enzymes that are part of the coagulation cascade. So let's begin with the molecule known as tissue factor pathway inhibitor or simply TFPI. Now, this is a polypeptide. And what the polypeptide does is it ultimately binds onto a complex that is part of the extrinsic pathway of the blood clotting cascade. So if we think back to the blood clotting cascade we have these two different pathways. We have the intrinsic and the extrinsic pathway and this polypeptide blocks essentially that extrinsic pathway from taking place.