ELi5 – Do puffed out cheeks when holding breath actually get used?

Question

In other words, if I jump in a pool and fill up my lungs and mouth with the stereotypical chipmunk cheeks full of air, do my lungs use any of that air in my cheeks as like a “reserve”? Or is it only the air that made it into the lungs that gets used?

In: 12

Answer 1

Medical student here! I’ll do my best to explain in simple terms.

Very basic anatomy of the respiratory system first: you have your mouth which is connected to your wind pipe which is connected to your lungs.

The air in your cheeks will not get used. This is because any air *above* your lungs (lungs are located in your chest) like the air that sits in you wind pipe (in the neck), or even higher, in your mouth, is considered “dead space”.

This means that the air *above* your lungs is essentially *too far away* to be involved in “gas exchange”. The whole point of breathing is to get oxygen into your blood and carbon dioxide out of the blood (this is what “gas exchange” means). Again, this can only happen in your lungs and not in any parts higher than that (windpipe and mouth)

Hope this helps!!

Answer 2

Medical student here! I’ll do my best to explain in simple terms.

Very basic anatomy of the respiratory system first: you have your mouth which is connected to your wind pipe which is connected to your lungs.

The air in your cheeks will not get used. This is because any air *above* your lungs (lungs are located in your chest) like the air that sits in you wind pipe (in the neck), or even higher, in your mouth, is considered “dead space”.

This means that the air *above* your lungs is essentially *too far away* to be involved in “gas exchange”. The whole point of breathing is to get oxygen into your blood and carbon dioxide out of the blood (this is what “gas exchange” means). Again, this can only happen in your lungs and not in any parts higher than that (windpipe and mouth)

Hope this helps!!