A pair of organs in the chest that exchange oxygen and carbon dioxide between the air and the bloodstream.
Air travels through the respiratory tract into increasingly smaller airways within the lungs, eventually reaching tiny air sacs called alveoli. Across the alveoli, oxygen enters the blood and carbon dioxide moves from the blood into the air to be exhaled.
The lungs also contribute to acid-base regulation and have important immune and metabolic functions.
QUICK FACT
The left lung is slightly smaller than the right lung because it shares space in the chest with the heart.
COMMONLY CONFUSED WITH
Respiratory system: the broader system responsible for breathing and gas exchange; the lungs are major organs within that system.
SEE ALSO