Does it move out of the capillary or into our capillary? Or does it move in both directions? So, to answer this question, we have to discuss the pressure that exists between the inside of the capillary and the outside, the tissue side of the capillary. Because ultimately, it's a difference in pressure that allows the movement of our fluid from point A to point B. And the two types of pressures we have discussed are hydrostatic pressure as well as osmotic pressure. So let's begin with hydrostatic pressure.