The Way It Happens:
Sneezing is something humans and even some animals like cats, dogs, and chickens do. Our question is why do we have to sneeze? Most of us would answer that our nose in order to get rid of dirt like irritants and mucus undertake the act of sneezing; this idea is not wrong but sure is incomplete. Scientists used to think that when dust, germs enter our noses, our brains send a signal and then sternutation or sneezing occurs as a reflex action. Same thing happens when we have a cold. We get an urge to sneeze because of the signal the brains send sensing the presence of mucus in our noses. You hold a breath in your lungs which was triggered by this signal. Pressure builds in your chest muscle because of holding this breath. Thus your tongue is made to touch the upper gum of your mouth and you breathe out fast through the nose which we call a sneeze. This is one classic way to answer why you sneeze.
Recreating a Sneeze:
A paper published in the journal FASEB in 2012 contradicts this typical idea saying there is a bit more to it. The tiny paddles that level our noses and sinuses called cilia has something to do with it. The researchers of University of Pennsylvania recreated a nose. Taking cells from nostrils of healthy adults they grew them in an incubator for a few weeks until they had the same sort of lining like the one in our sinus along with cilia. Puffing air on the lining scientists created the same scenery as the sneeze. They could not but help noticing how the air triggered the cilia to move back and forth quite a few times and after a few minutes there was a sneeze. The question remains why was it so active for this long? The cilia here were resetting our entire nasal space, not just the irritation zone, acting like a brush. So according to biologists the cilia is like the restart button that computers have to reboot them from time to time.
The Reverse Experiment:
Not all sneezes reboot the noses. This group of scientists mentioned before also used nasal cells from people who had sinusitis. These kinds of patients have runny nose, nasal congestion and the like. When the air was puffed into the lining of their nose they discovered that the cilia didn’t move faster and they came to conclusion that these patients had adjust with the cilia that could not reset the post-sneeze. This might also generate in further development of treatments for it.

Benazir Elahee Munni