Why Your Body Does Weird Things

Scientists once believed yawning was a way to get extra oxygen to a sleepy brain. On the contrary, recent studies say we yawn to regulate body temperature -- specifically, to cool our brains. Research has shown that people yawn most often when the ambient air temperature hovers around a comfortable 68º F (20º C), but yawn less often as the heat reaches their body temperature and beyond. But why does your brain get hot in the first place? Brain temperature rises with sleep deprivation -- just like yawning does. And that's just one of your body's weird quirks.

Why Do You Yawn?

Yawning isn't a way to get extra oxygen to your brain, despite what scientists once believed.

Key Facts In This Video

  1. Babies begin to yawn during the second trimester. It may have to do with proper brain development. 00:25

  2. Scientists believe that yawning has developed as a way of cooling your brain. 00:40

  3. Contagious yawning begins in children around age 4–5. This is also when empathetic behavior begins. 01:28

Why Does Scratching Satisfy An Itch?

It all comes down to a special kind of skin receptor.

Key Facts In This Video

  1. Itches, pain, and heat all follow the same neural pathways, but itches trigger special receptors called pruriceptors. 00:38

  2. Pruriceptors are attuned to touch as gentle as the pressure of a fly's legs. 01:12

  3. Itching activates more skin cells than the pruriceptors, which may be drowned out by these other signals or just turned off. 01:52

What Are Eye Floaters?

They're not on the surface of your eye, and they don't actually float.

Key Facts In This Video

  1. The vitreous in your eye is about 99% water and 1% collagen. 01:01

  2. Eye floaters are neutrally buoyant, so they don't actually float. 01:52

  3. Multiple new eye floaters and bright flashing lights could be symptoms of a retina that's about to detach. 03:20

What Makes Your Limbs Fall Asleep?

You can thank your nervous system.

Key Facts In This Video

  1. Exterior pressure squeezes nerve pathways so that the nerves can't transmit their impulses properly. 00:41

  2. Stretching and moving a limb that's fallen asleep should cause the nerves to function again. 01:20

  3. Some nerve fibers have thicker insulation around them, and take longer to resume transmitting impulses after they've been squeezed. 01:59

Written by Curiosity Staff June 8, 2016

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