Now let's move on to the osmotic pressure. So, osmotic pressure, also known as oncotic pressure, and we'll see why in just a moment, is the pressure that exists between the two sides of a semi permeable membrane as a result of a difference in solute concentration between the two sides of that semipermeable membrane. In this case, our semipermeable membrane is the wall of the capillary. So, if we examine the following diagram, we see that inside our capillary, the blood plasma actually contains a higher concentration of solute molecules. It contains more proteins, it contains more ions, and so forth. And as a result, it has a greater concentration of solute.