How do our lungs not fill up with dust?
In: Biology
The body has several layers of defense for preventing that. Firstly, you have nasal hair that works to trap dust in the nose, and a sneezing reflex to clear it. You also have mucous membranes in the nasal passages and the throat to trap dust there, and a cough reflex to clear that part. Finally, the sides of the lower airways are covered in microscopic cilia – basically little wiggly tentacles – that pulsate upwards constantly. Together with the mucus layer that covers them this, they form a kind of sticky conveyor belt that is constantly acting to move dust out of the lungs and upwards. When it makes it to the throat, your cough reflex takes over and moves it out. This is one of the reasons that smoker’s cough is typically worse upon waking – cigarette smoke throughout the day interferes with the cilia and slows down the conveyor belt, until you go to sleep and stop smoking. So when you wake up all the nasty stuff is waiting to be coughed out.
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