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Ask Dr. Universe anatomy
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Why can’t we tickle ourselves? – Malcolm, 3, Washington

Dear Malcolm,

I was surprised the first time I saw a human transform into a tickle monster. They curled up their fingers and rhythmically poked someone else’s armpits. That is something a cat would never do.

I asked my friend John Wright about it. He’s a retired psychology professor at Washington State University.

I learned that there are two kinds of tickling.

The first is the light tickle you feel when someone gently brushes your skin. Like when someone uses a feather to barely touch the inside of your arm. Scientists call that knismesis.

It turns out you can totally tickle yourself that way. But the feeling will be much more tickly if someone else does it.

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Why do we need to hydrate? – Victor, 9, Ohio

Dear Victor,

Is there anything better than lapping up cool water on a hot day?

I talked about why we need to hydrate with my friend Ed Johnson. He teaches classes about the human body in the School of Biological Sciences at Washington State University.

It turns out that up to 60% of an adult human’s body is water. A kid’s body contains even more water than a grown up. When you were a baby, you were about 78% water.

Humans use that water for all kinds of things. It keeps you cool when you sweat. It removes waste when you pee. It moves important stuff around inside your body. It even cushions your brain and spinal cord.

But staying hydrated is really about your cells.

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Why do we have nose hairs? – James and Zion, 10, Virginia

Dear James and Zion,

Despite being a curious science cat, I must confess I haven’t spent much time looking up human noses. But I have noticed that human nostrils can be a bit…furry.

I talked about what’s inside your nose with my friend Edward Johnson. He teaches classes about the human body in the School of Biological Sciences at Washington State University.

He told me that nose hairs only grow in your nose’s vestibule. That’s the inside of the part of your nostrils that you can flare out. The nose hair’s job is to filter the air you breathe in through your nose.

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Do insects have blood in their bodies? – Raman, 7, Washington

Dear Raman,

You probably don’t look like an insect. You don’t have feelers or wings. You keep your skeleton inside your body instead of on the outside. But what about blood? Do insects have blood like yours?

I talked about this with my friend Richard Zack. He’s an entomologist at Washington State University.

“Insects have hemolymph,” he said. “It’s very similar to blood.”

Zack told me hemolymph moves differently through the body, and it doesn’t do everything blood does.

Humans and other mammals have closed circulatory systems. That means their blood travels in blood vessels. A heart pumps the blood all over the … » More …

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Dr. Universe: Why do we have spines? - Jessie, 10, Covina, Calif.

Dear Jessie,

Your spine is more than just a long line of bones. It’s the secret to jumping for joy, the base for all your best dance moves. Every time you run, climb, walk, and play, your spine is right there with you.

“Without a spine, our ability to move would be completely different,” Edward Johnson said.  Johnson teaches Human Anatomy in the School of Biological Sciences at Washington State University. He is very curious about how all the parts of your body work together.

All creatures with spines are called “vertebrates,” including humans. They get this name from their vertebrae: the special bones that make up the spine. Your vertebrae are different shapes and sizes, but they all connect together.

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Dr. Universe: Why do we have a belly button? – Jane, 9, Kennewick, WA

Whether you have an innie or an outie, pretty much all us mammals have a belly button. But before you had a belly button, there was actually a different bit of anatomy in its place. While you were still growing inside of your mother, a small, bendy tube on your tummy connected the two of you. This tube is how you got pretty much everything you needed to grow before you were born into the world. Read More ...