So let's begin by describing the quick acting pathway, the extrinsic pathway, and this is shown by these black arrows. So question number one is how exactly do we initiate what begins the extrinsic pathway? Well, let's suppose somehow this endothelial cell ruptures. So we have a hole that forms in the membrane and that allows the blood to move from the lumen side and into the outside the tissue area, down its pressure gradient from a high pressure to a low pressure. Now, as soon as this endothelial cell is damaged, it will expose a special glycoprotein membrane known as TF, which stands for Tissue factor. Now, this glycoprotein wasn't there before.