Wrinkly fingers, paper cut pain, tingling feet: What's going on in our bodies?

Ever wonder why our skin starts to look a prune after staying in the hot tub for too long?

Or what's really happening when our legs fall asleep? Or how getting tiny paper cuts can ruin a good day?

Dr. Raj Bhardwaj explained a few little medical oddities on Tuesday's Calgary Eyeopener. 

Here is an edited version of their conversation.

• MORE ALBERTA NEWS | Donate your old Christmas tree to a porcupine
• MORE OFFBEAT | Deer saved from icy Alberta river in rescue caught on video

Q: Why do we close our eyes when we sneeze? And is it true that if you sneeze with your eyes open, your eyeballs will pop out?

That's a lie.

If you practise, you can actually learn to sneeze with your eyes not closed.

Back in 1882, the New York Times wrote an article that a woman on a streetcar had a sneezing fit and then popped her eyeball out. That's not possible.

I have a theory that maybe this lady already suffered a fracture. There's a paper-thin bit of bone between the sinus in your cheek and your eye socket. If that bone has been broken then when people blow their nose then skin around their eye fills full of air. But not pop out.

Q: Why do our fingers wrinkle in water?

You'd think it's simple osmosis, but it's not so simple. But your entire body doesn't wrinkle. Special skin that doesn't have hair on it doesn't wrinkle, it's something about the skin.

Plastic surgeons discovered that fingers with a cut nerve supply won't wrinkle. It has a specific nerve reflex that allows the wrinkling to happen.

We think there's an evolutionary benefit to having wrinkled fingertips and trying to grip on to wet things, like swinging from the trees in the rain so you don't slip off and fall.

Wet fingers can manipulate wet objects better. 

Q: Why do paper cuts hurt so much?

There's no good research on this, probably because it's hard to have volunteers get paper cuts inflicted on them.

But if we break it down — first of all, edges of paper are very ragged, secondly fingertips are incredibly sensitive.

The density of sensory nerves on your fingertips are way higher than anywhere else on our body.

And they don't cut very deep. They cut to the nerve layer, exposing the nerves.

Q: Why do we get pins and needles?

We have some long nerves in our body, those nerves can get compressed, so can the blood supply to the nerves.

The brain doesn't like it and interprets it as pins and needles.

There's three distinct sensations. First, a buzzing tingling happens after a few minutes. After that, there is what researchers call "velvety numbness" after 10 minutes of compression. Once the compression is released, there's a painful pricking as the blood flows back and the nerves wake back up.

Hot peppers can create the same effect.

With files from the Calgary Eyeopener