Merck Frosst
Patients and Caregivers
The main job of your lungs is to supply oxygen to the blood and to remove carbon dioxide from your blood as it passes through the lungs.
1
To do this, you breathe air in through the mouth and nose.
2
The air passes through the windpipe (or trachea) and into small passages in the lungs called bronchi.
3
At the ends of the smallest airways are air sacs or alveoli. This is where the gas exchange happens in the respiratory system. Your blood takes in oxygen in exchange for carbon dioxide which you then exhale.

This site is for residents of Canada. / This site was updated on October 27th, 2008.