SciShow host Michael Aranda explains why humans and some species of animal sneeze.
Enjoy!
Why do we sneeze? The long-standing answer has been that sneezing is a reflex. When irritants — such as germs, dust, pollen, animal dander, or pollutants, just to name just a few — infiltrate the nose lining, the brain sends out a signal to get rid of it. That triggers a deep breath, which gets held in the lungs. As a result, the chest muscles tighten and pressure builds. The tongue pushes against the roof of the mouth, forcing breath to come out fast through the nose — Achoo!