Eli5: How do our lungs output carbon dioxide?


Is there an exhaust valve that opens when I breathe out?

In: 3

Your lungs exchange gas between the atmosphere and your blood, it lets oxygen from the atmospere into your blood and lets carbon dioxide from your blood into the atmosphere.

When you breathe in your lungs fill with fresh air with oxygen. As blood flows past your lungs it drops off CO2 and picks up oxygen. So when you exhale you are breathing the CO2 out into the air, making room for another breath of oxygen.

Your blood contains dissolved gases namely oxygen and carbon dioxide. At all times. It’s never like all the oxygen is exchanged into co2. They both are present at all times in the body. But their quantities are different. In fact, you’ll die if given 100 percent O2 for a certain time.

So all the fluids ( liquids and gases) have a tendency of flowing from area of higher concentration to lower concentration meaning like imagine a ball going down a hill, when the ball is at the top (area of high concentration) so it rolls down ( to area of low concentration) but in blood we use the term ‘pressure’.

So wherever O2 is more and co2 is less in blood (at the organs/cells), co2 from the organ goes into blood, the blood then goes to lungs where co2 is high (because just got picked up from the organ) and O2 is low (comparatively), so O2 from lungs and the inhaled air go into blood and excess co2 from blood to lungs to outside

Hope it helps, feel free to ask any questions 🙂