I recently learned about the pressure of the atmosphere against the human body. It just so happens that this force is in equilibrium with the human body, so we do not feel any pressure. Although if we fly an airplane, we do. This got me to thinking, what of the blood in our veins? Does this not exert a force outward, which I can only assume is in equilibrium with a force acting against it. So now, I have the pressure of the atmosphere acting on me, as well as a pressure from my blood acting in another direction. Is this correct? Are there any other fluids in the human body (mucus?) that I am neglecting?