So we have factor twelve, we have factor eleven and we have factor nine that are part of the intrinsic pathway and then we have the factor ten which is basically the initiation of the final common pathway. It's that factor that is part of that converging point between the intrinsic and the extrinsic pathway. Now let's move on to heparin and heparin cofactor two. So heparin cofactor two is actually a molecule that enhances the activity of heparin. So let's begin by discussing what heparin actually is. So if we examine the connective tissue found surrounding our blood vessels we're going to find immune cells known as mast cells.