So as our blood plasma, as our fluid moves along our blood vessel, along the capillary, that fluid exerts a force and it pushes against the walls of the capillary. And this is what we call the hydrostatic pressure. Hydro simply means water, because our blood plasma is predominantly water. And static simply means we have these forces. So hydrostatic means the force as a result of that fluid that moves along our capillary system. Now, let's take a look at the following diagram that describes our blood vessel.