WHAT THEY DO
high school that your lungs bring in oxygen and move it to the blood (inhale) while taking carbon dioxide out of the blood (exhale). Not as well-known: Your lungs are also “immunologically the biggest filter ever,” says Ana Zamora Martinez, M.D., a critical-care pulmonologist at the Mayo Clinic. Their branched structure’s tiny passages for blood and air naturally restrict pollution, germs, and even blood clots. And the lungs help regulate blood pressure by processing a hormone
