Okay. So now that we understand filtration pressures more generally, let's talk about glomerular filtration pressure. Glomerular filtration pressure is determined by three factors. First up, we have glomerular hydrostatic pressure, and the main principle at work here is, of course, hydrostatic pressure. This one will be largely determined by systemic blood pressure. What's happening here is high resistance causes the blood to push against the walls of the glomerular capillary. This force favors filtration. Basically, the blood pressure will be pushing fluid through the filtration membrane. The actual pressure happening is pushing fluid against that membrane. And so you can see in our image, we have our blood, it's pushing against that filtration membrane, and then all of the water molecules, electrolytes, you know, little tiny solutes get through and end up in the filtrate. This is going to be a pretty powerful force. It's gonna be about 50 to 55 millimeters of mercury.
Now, our next force is capsular hydrostatic pressure. This is also just the basic principle of hydrostatic pressure. But what's happening here is that the filtrate in the capsular space builds up its own hydrostatic pressure. This force is actually going to be opposing filtration. Because what's happening is that the hydrostatic pressure of that filtrate pushes fluid back into the capillary or pushing against the filtration membrane from the opposite side. You can see we have this filtrate here and the hydrostatic pressure of that filtrate is pushing on the filtration membrane in the opposite direction. This force is, lucky for us, pretty weak. It's about 10 to 15 millimeters of mercury.
And then our final pressure is glomerular colloid osmotic pressure. The main principle here, of course, being colloid osmotic pressure. What's happening is that the high concentration of plasma proteins, specifically albumin within the capillaries, is creating an osmotic gradient. Remember, water wants to move from low solute concentration toward high solute concentration. And because the blood in the capillaries is now highly concentrated since all the fluid has moved out that is looking very attractive for all those water molecules. And so this force also opposes filtration. The osmotic gradient is drawing water back into those capillaries, or that's where the water at least wants to be. They can see our, in the little cartoon that we just saw in the previous video, we have our little water molecules hanging out in the filtrate, and they're seeing that high concentration of plasma proteins and they're like, "Hey, we wanna go join that party." Right? So they're getting drawn back toward the capillary. This force is gonna be about 30 millimeters of mercury.
Now, when you add all those numbers up together, our net glomerular filtration pressure is going to be about 10 millimeters of mercury favoring movement through the filtration membrane. This number is actually very important. Our body really wants to keep that pretty consistent because if this number changes by even like 10 to 18%, it can actually have devastating effects on the body, which we will talk more about in our glomerular filtration rate video. So I will see you guys in our example that we can learn how to actually solve for this number together. So, I will see you guys there.