Why Do We Have This Cilia All the Way Down Our Airways?

The cilia are like little bits of hair or like eyelashes. When certain foreign particles get stuck in the mucus, these cilia kind of beat proximally. So they push the mucus in a wave, which hopefully things are stuck in it like dirt, pollen, bacteria, pollutants. And it pushes it up the trachea, higher, higher, high, until it gets kind of in your pharynx region and you can produce sputum.