Air movement in body cavities

[tanas]

Can someone explain why air rises to the highest point in the body cavities like peritoneal/pleural?

 

[jbriggs444]

Can someone explain why air rises to the highest point in the body cavities like peritoneal/pleural?

For the same reason that [a heavier than flesh] fluid sinks to the bottom of such cavities.

 

[sophiecentaur]

Can someone explain why air rises to the highest point in the body cavities like peritoneal/pleural?

Bubbles?

 

[tanas]

Buoyant force? I guess that that we can assume that gas in cavities is actually submerged in fluid? There is tiny amount of fluid in this cavities that keep organs and serous surface stick to each other by surface tension.

 

[sophiecentaur]

Buoyant force? I guess that that we can assume that gas in cavities is actually submerged in fluid? There is tiny amount of fluid in this cavities that keep organs and serous surface stick to each other by surface tension.

Although there could well be small amounts of gas in amongst our organs, they are likely to be dissolved eventually in the fluids. Any small amounts of gas can give severe discomfort, as in decompression sickness, which is suffered by divers and air embolisms. CO₂ is not too much of a problem because it dissolves but tiny nitrogen bubbles which have come out of solution as the pressure reduces take a long time to dissolve, once they have joined together. Hence, divers decompress slowly enough to let the body get rid of the tiny bubbles.
Large amounts of gas are definitely not a good idea. I had laparoscopic surgery, some years ago and they fill your peritoneum with CO₂ to separate out the organs so that they can work in there. The sensation afterwards was truly weird. I likened it to having a bag of groceries in there until the CO₂ gradually passed out (via the normal route!) and the organs nestled together again, properly.