Fluid dynamic question?

[millworker301]

I would like to ask a few questions about fluid pressure dynamics.

In a closed system, would a higher altitude increase or decrease the pressure of the fluid in the system?
If you had 2 different systems of fluid at the higher elevation how would the density of the fluid affect the pressure change?

In case you are wondering. The systems that I am referring too are in your body. One system would be the blood system and blood pressure, the other system is the CSF (cerebrial spinal fluid) system which surrounds the spine and the brain.

Thanks for any input all of you may have.

Working on a medical problem.

 

[btrueblood]

Because of the relatively soft tissue surrounding the closed fluid system, the absolute pressure should vary with elevation or other external pressure changes. Not sure that density would affect this base pressure, though it obviously would affect the dynamic pressures in the blood vessels, etc.

 

[millworker301]

ok. First I am not an engineer but I do work in industrial maintenance and I have had some heat transfer and fluid flow classes in the past. So I will try to discuss this as best I can. Thanks for the point of it being soft tissue system which it is. It seemed as the higher elevation increased the blood pressure but there is no way to measure the CSF pressure. Well, there is a way to measure that but it takes a lumbar puncture to do it and that was not realistic. Does that sound correct to you that the increased elevation would increase the blood pressure? I see that you say that the absolute pressure should vary with elevation or other external pressure changes, but you didn't state which direction. Would the outside pressure not be lower at a higher altitude? Which way do you think, by theory, this should drive the blood pressure or CSF pressure?