What happens in our bodies during a breath to cause the atmospheric pressure to suck the air?
In: Physics
The short answer is that it changes the volume of your chest cavity. This makes your lungs larger which means the air in them is at a lower pressure than the ambient air pressure which then pushes air into your lungs.
First, there’s your diaphragm which runs along the bottom of your ribcage. When it contracts, it pulls down to make your lungs expand. It also pushes the organs below it down which is why your belly pushes out a bit when you breathe.
You also use your intercostal muscles between your ribs to expand your ribcage outward to add additional volume and pull in more air. You can breathe with there alone, but it’s more effort than your normal breathing that uses a mix of diaphragm and intercostals.
It’s not part of reflexive breathing, but moving your shoulder joint can also expand or shrink your chest. That’s why athletes train their breathing so they don’t try and breathe in while their motions are trying to compress things.
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