All this time we thought lungs were just for breathing. It turns out they also play a key role in how blood is formed, suggests a study in Nature out of the University of California-San Francisco. Scientists studying the lungs of mice discovered to their surprise that the lungs produced about half the platelets, blood components necessary for stanching, in the creatures' circulation, according to a release. It's been long assumed that most if not all of these platelets were generated in bone marrow, not the lungs. What's more, they also discovered that lungs have what New Atlas describes as "a backup reservoir of blood stem cells that can step in when those in the bone marrow run dry," and that these cells travel freely between the marrow and lungs.
"This finding definitely suggests a more sophisticated view of the lungs—that they're not just for respiration but also a key partner in formation of crucial aspects of the blood," says senior author Mark Looney. "What we've observed here in mice strongly suggests the lung may play a key role in blood formation in humans as well." If that holds true, researchers say the findings could not only lead to better treatment of blood diseases but improve the odds of successful lung transplants. The telltale clue came in the discovery of a large number of megakaryocytes, cells that produce platelets, in the mice lungs, explains the San Diego Union Tribune. It's been known for a while that lungs are capable of making platelets, but the study suggests that role has been greatly understated. (Your lungs might be able to smell.)