And these blood clots are basically mesh like networks of these individual fiber molecules that basically create the mesh like structure that ultimately forms the blood clots. And these blood clots can basically coagulate and they can seal off that rupture, that cut, and that prevents the leakage of blood out of that blood vessel and into that surrounding tissue. Now, if we actually examine the blood clot in cascade, we'll see that there are two important pathways. We have the extrinsic pathway and we have the intrinsic pathway. So let's begin by focusing briefly on the extrinsic pathway. So in the extrinsic pathway, what happens is, once we have the cut in the endothelium of the blood vessel, that exposes an important interior glycoprotein that wasn't there before.