How does a breath suck air into our lungs?


What happens in our bodies during a breath to cause the atmospheric pressure to suck the air?

In: Physics

You have a sheet of muscle just below your lungs called your diaphragm. You move this muscle downwards, causing the space of your lungs to enlarge and thus have lower pressure and the air rushes into your lungs to fill that space.

When we breath, it’s us using our intercostal muscles. The diaphragm moves up, decreases the volume in our lungs, causing a different pressure so air gets sucked in. Something like that idrk

The muscles of the chest wall and diaphragm flex, increasing the size of the chest cavity and the volume of the lungs. Because the volume of the lungs have increased with the same amount of air in them, the air pressure within decreases and the external air pressure forces more air into them provided there is a path to do so (e.g., the trachea isn’t blocked).

You have a muscle sitting right below your lungs. When you breathe in, this muscle forcefully pulls down, which pulls on the lungs, expanding them. Once expanded, suddenly the little sacks inside the lungs have a lot more volume to them, but still the same amount of air, which means the pressure inside them dropped. Because of this, air starts rushing in from the high-pressure environment from outside to the low-pressure environment inside your lungs.

When you breathe out its the opposite. The muscle pushed up, squeezing the lungs and squeezing all the air out of them.

Thanks. Current comments suffice.

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.

I like to think of an accordion. When you expand it, air comes in, when you compress is, air goes out. The rib cage is just like that.