Where do tears come from?

Where do tears come from?

Planet Science investigates...tears

Richa Patel emailed us to ask "What makes tears?" We put our investigating hat on and set off to find out...

Eyes are amazing things, so we need to protect them. You make tears every time you blink. When you blink, the tears spread out in a thin film over your eyeballs. Tears are made in tear glands on your upper eyelids. The tears flow into your eyes through tiny tear ducts and help to keep your eyes free things that could irritate them, like dust. Even if you're asleep, tears are still being produced! Your tears have a tiny bit of salt in them, which is antiseptic and helps to prevent eye infections. Used tears go down two tiny holes in your upper and lower eyelids to the back of your nose, where they are swallowed or blown out with your snot!

Crying girl_76549131

If something gets in your eye and irritates it, your tear glands make more tears to try and flush the irritant away. These are reflex tears. If something makes you sad or extra happy, your tear glands produce emotional tears. If you produce lots of tears, they can't all drain into your nasal cavity, so they overflow and run down your cheeks.

What if you cry whilst you're chopping onions? Planet Science explains it all here

 

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