Human systolic pressure is 16 kPa and diastolic 11 kPa but Earth atmosphere pressure is 101.325 kPa. I don't understand why when we are hurt we bleed instead of air enter into our body. ¿How can blood be "stronger" than atmosphere pressure? **Edit:** <br/> I edited my question because I don't have enoght reputation to make comments. <br/> @KareemElashmawy, I found in Physics.SE [Gauge pressure vs. absolute pressure](https://physics.stackexchange.com/a/20461/149711). So, this means that a **16 kPa** of systolic and **11 kPa** of diastolic is **really** **117,325 kPa** of systolic and **112,325 kPa** of diastolic (pressure + atmospherical pressure) and this is why we can bleed (**inner pressure - outside pressure = +16 kPa and +11 kPa = bleeding**)?.