We breathe in oxygen (O2)
Oxygen (O2) moves from the alveoli into the blood capillaries
Carbon dioxide (CO2) moves from the capillaries into the alveoli
Oxygenated blood travels to the heart and the rest of the body
Carbon dioxide (CO2) is eliminated when we breathe out
Cells produce energy and a waste gas called carbon dioxide (CO2)
Capillaries carry deoxygenated blood
6
7
5
4
2
1
3