Atmospheric air pressure on the human body

  • Thread starter fog37
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  • #1
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Hello,
It is well known that the atmospheric air pressure is significantly strong but our body does not get crushed by it because and equal pressure pushes from the inside our body.
That said, does it mean that air can exist and be diffused inside solid organs like the lungs, our heart, etc. and exert its pressure as it would without permeating the organs? Is the pressure inside the solid body parts equal to atmospheric pressure? How does that happen? Does air diffuse through solids like that?

Thanks!
 

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  • #2
russ_watters
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Hello,
It is well known that the atmospheric air pressure is significantly strong but our body does not get crushed by it because and equal pressure pushes from the inside our body.
That said, does it mean that air can exist and be diffused inside solid organs like the lungs, our heart, etc. and exert its pressure as it would without permeating the organs? Is the pressure inside the solid body parts equal to atmospheric pressure? How does that happen? Does air diffuse through solids like that?

Thanks!
No, air doesn't need to be inside your organs to balance atmospheric pressure. Think about a well-filled water balloon; It's just a bag of water.
 
  • #3
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Does air diffuse through solids like that?
Yes. Our lungs, and also other animals use Oxygen from the air, and excrete CO2.
Handily, most plants do the reverse process.
 
  • #4
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Ok, so, not be crushed, the internal pressure of the organs inside our body must balance the atmospheric air pressure. I thought that would be possible because we inhale air at the same pressure as atmospheric pressure and that air did the balancing, not the solid stuff inside the organs...
 
  • #5
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There is no reason why the organs in your body, which are mainly water, would be subject to any pressure differrrnt to ocean water
 
  • #6
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Ok, so in the ocean the pressure of water at a particular depth is the air pressure + rho*g*h where h is the depth. Close to the water surface, the water pressure is indeed atmospheric pressure. Back to the inside of the body, as most organs are made of water, their internal pressure will be approximately atmospheric air pressure. Is that the reasoning?
 
  • #7
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Yes, but it's fascinating that animals evolved lungs, which work by producing small pressure differences, enabling what we call respiration..
 
  • #8
russ_watters
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Ok, so, not be crushed, the internal pressure of the organs inside our body must balance the atmospheric air pressure. I thought that would be possible because we inhale air at the same pressure as atmospheric pressure and that air did the balancing, not the solid stuff inside the organs...
No, solids and liquids have pressure of their own.
Back to the inside of the body, as most organs are made of water, their internal pressure will be approximately atmospheric air pressure. Is that the reasoning?
These things don't follow. It doesn't matter if the interior of your body is water or solid calcium salt (your bones). It has the pressure it has because the atmosphere is applying pressure to it, so it applies pressure back.

The reason we can generally ignore this pressure is that it is uniform, so it doesn't cause any internal stress.
 
  • #9
sophiecentaur
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No, air doesn't need to be inside your organs to balance atmospheric pressure.
To be precise, the partial pressures of the dissolved atmospheric gases in our tissues is the same as the partial pressures in the atmosphere. If the ambient pressure changes then there will be (slow) diffusion to re-establish equilibrium. Decompression sickness is caused by changing the ambient pressure too quickly for the diffusion to be fast enough to prevent the formation of bubbles.
All our tissues (except, perhaps dental enamel) are composites and have some water in them. We are more like a wet sponge than a lump of steel, in that regard. But I think you could say that a solid like a block of metal would absorb some atmospheric gases eventually. The timescale would be greater than geological, though and equilibrium is never reached. The same is almost true for the special oils made for high vacuum technology.
 

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