Though the lungs would be full of liquid, what about the stomach, intestines, colon, inner ear and other parts of the body?
Again, the point isn’t to make the human body impervious to compression. The idea is to eliminate the air spaces in a rigid suit. The pressure outside the suit would be much higher than inside, but since it would be filled with liquid, it wouldn’t have to be two feet thick to avoid crushing. We’ve all seen the demonstration of a bathosphere taking a styrofoam cup to depth and bringing it back the size of a thimble. If you sent an unmanned bathosphere down, filled with water, with the cup inside, it wouldn’t be compressed (well, not noticably anyway). If it were practical to fill the bathosphere with water, you could also re-engineer it with thinner walls and glass and while you’re at it, make it a suit, see?
It also seems that people are confusing liquid oxygen (oxygen cooled to its liquid state), with hyper-oxygenated liquid (a liquid capable of holding far more oxygen in solution than water).
The fluid is not nitric oxide but is an oxygen saturated flouro-carbon.
Nitric oxide as an inhalant has been used to increase oxygen uptake in
infants. See http://www.update-software.com/ccweb/cochrane/revabstr/ab000399.htm, and http://www.update-software.com/abstracts/Search%20abstracts/ab000509.htm
Research on the oxygen saturated flouro-carbon fluid was started in the late fifties by the U.S. Navy. It has been used in successful tests with small animals, however the bronchial passages in the larger animals (small dogs) are too small and too long to allow enough fluid to pass in and out of the lungs. The chest muscles/diaphragm weren’t designed to pump fluid.
There have been recent tests on infants with oxygen saturated flouro-carbon fluids,
Regarding what happens to the human body underwater, as long as the airspaces - lungs, sinus cavities, and middle ear - are filled with air at the same pressure as the ambient pressure, the pressure doesn’t directly cause damage. It does cause the body to absorb more nitrogen and more oxygen. Above a certain oxygen partial pressure, oxygen becomes toxic and causes convulsions. The exact partial pressure varies with the individual and the circumstances and is subject to a fair amount of discussion and controversy in the technical diving community.
The absorbed nitrogen returns to the blood as ambient pressure is decreased and if it returns too fast, bubbles will form that the lungs can’t transfer to the exhaled air fast enough and DCS (decompression sickness) or the “bends” can occur.
A human - Pipin Ferreras - has made free dives to about 400 feet without adding air at ambient pressure to his lungs as scuba divers do. Just holding his breath. His lungs actually collapse to a fraction of the normal size and his internal organs move up to fill part of the space.
The sperm whale have been tracked to depths of over 8000 feet.
I do not believe you are entirely correct. A rigid structure used for traveling underwater, such as a bathysphere, is intended to support large pressure differences between the inside and outside. Whether you have air at one atmosphere of pressure inside the structure, or an incompressible fluid at one atmosphere of pressure, the pressure difference that must be supported is the external pressure minus one atmosphere.
One difference between using a compressible fluid (air) and an incompressible fluid (water or perflourocarbon), is that if the structure fails (for example, springs a leak) the resulting rapid equalization of pressure between inside and outside is somewhat less traumatic for the incompressible fluid.
If you want your structure to be thinner and lighter, you need the internal pressure to be the same as the external pressure–at which point you might as well use a completely flexible suit. You can’t use a flexible suit if it’s full of air, since, as you correctly point out, it’ll collapse in a rather spectacular fashion.
Actually, IIRC it’s pale blue.
“clear” and “pale blue” are not incompatible terms. Clear means you can see through it; it doesn’t imply anything about color.
I’ve also read that liquid oxygen is supposed to be pale blue. I didn’t notice it being particularly blue, but it wasn’t like I was looking at a bottle of it… just a blob maybe 1-2 cm thick. In that quantity it didn’t seem noticeably more blue than, say, water.