Humans absorb oxygen from air in the lungs, fine.
If you put water in the lungs the dissolved oxygen in the water somehow(?) doesn’t get absorbed, fine.
But, somehow(?) fish can absorb oxygen from water.
OK? How come human lungs can’t absorb oxygen from water but fish gills can absorb oxygen from water?
It’s literally just diffusion?
**EDIT: This thread is cancer. I will try to find the answer somewhere else. Turning off replies.**
In: 0
Fish’ gills are like sheets that are designed to allow water to flow over them at high rates, allowing the water that has had oxygen removed to move on quickly so that the next, oxygenated, bit of water can take its place.
Lungs are made of millions of little sacs designed to have a high surface area, sacs that would be hard to empty out without squeezing them out completely like a sponge – taking a lot of effort and squeezing room we don’t have.
Water also has a lower concentration of oxygen than air does, since you’re relying on the amount of air dissolved and how quickly you can get it out of the water, as opposed to breathing air where the oxygen is freely available. The mucus lining of our lungs just hasn’t evolved to efficiently pass dissolved air through either.
In short, you’d need to be able to breathe really really fast, and since our lungs are inside our body and would need to be emptied each time, you’d need to breathe really really hard.
There have been some experiments that have shown an ability to breathe liquids that have an extremely high free oxygen content, even through our intestines instead of our lungs.
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