questions to me before. I've looked at eye bags, eyebrows and here's another eye popping

question for you now. It was sent in my hugessfan on YouTube who asks Why do we close our eyes

when we sneeze? Now first of all lets debunk an old school myth. If you sneeze with your

eyes open your eyes do not pop out on springs like you see in the cartoons. That will not

happen! Alight? OK? Ok, goo. Now sneezing is involuntary.

When you are struck down by the common cold or man flu as we like to call it your nasal

cavity is more swollen and more sensitive and any irritation will cause you to sneeze.

Something like pollen, or dust, or even fur from your mate's cat, if it gets up your nose.

To get technical, an irritant when it contacts the nasal mucosa it triggers the trigeminal

nerve, which sends a signal to your brain which goes to the lower part of your brain

known as the medulla. And then you know what happens the chest expands,

your lungs fill with air, and achoo, you sneeze snot everywhere. And James did a really good

film on where snot comes from, I'll put a link to that at the end of this one. But get

this, you sneeze out over 5000 droplets of mucus and air at speeds up to 100 miles an

hour. But of course you will all that high octane action because your eye lids actually

pull down your curtains. But why do you sneeze? It's one of science's

big mysteries. We think it's an involuntary response just like if you get tapped just

under your knee cap your leg goes flying up. So what could be causing it? Well you could

be shutting your eyelids because as you sneeze out the germs and bacteria they don't fall

on your eyes. Or maybe your eyelids shut down because they're one of a series of muscles

that tighten because of that involuntary response. Some people's eyes do actually stay open,

if you're one of those people then please do let me know in the comments below this

video, or indeed, if you know of anyone. That's all the time I've got right now. Please do

keep sending me in your questions on twitter, on facebook, or in the comments below. Until

next time happy head sneezing, head squeezing.