with Chloe and the Nurb.

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Flashlight?

Check.

Rope?

Check.

Trail mix?

Check.

Picture of my mommy?

Um, check.

Now, will you tell me where we're

going with all this stuff?

We're going "Under the Surface of the Skin!"

Skin, skin, skin, skin, skin, skin.

Ahem.

Excuse me.

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Wow.

This is pretty cool.

I mean, I see skin all the time-- soft skin, wrinkly skin,

light skin, dark skin-- but I never

thought about what's under the skin.

What's on top is just the beginning

of the skin you're in.

The skin actually has three layers.

There's the epidermis, the dermis,

and the subcutaneous fat.

I don't know who gave you your elevator operating license,

but I would like to have a word with them.

Oh Chloe, you don't need a license to operate an elevator.

OK.

My stomach's feeling better.

Whoa!

The epidermis is like a skin cell factory.

New cells are being born at the bottom all the time

and slowly making their way up to the top.

It takes the cells about four weeks to get all the way up,

and by the time they finally make it to the surface,

they're dead.

So I'm like a skin cell graveyard?

[WOLF HOWL]

Precisely.

And you're shedding dead skin cells all the time.

Wow.

What else is up here?

The epidermis also contains melanin,

and it's what makes skin darker or lighter.

The more melanin a person has, the darker their skin will be.

Skin comes in many beautiful colors,

like my lovely lavender sheen.

I've heard melanin also helps protect you from the sun.

It sure does.

But even melanin can't do it all,

and that's why we wear sunscreen to keep from getting burned.

So what has the dermis done for me lately?

Let's go find out.

Ooh, look at all this stuff down here.

I see blood vessels, and that's a nerve ending over there.

I know nerve endings send messages to the brain,

but what is the skin trying to tell the brain?

Well, it's a touchy subject.

OK, I'm going to guess that that terrible pun means

that this has to do with the sense of touch.

Smarter and smarter you get.

Think of all the things your skin touches--

rough tree bark, a cold snowball,

a nice cup of hot chocolate.

Nerve endings read all of these sensations

and tell the brain and nervous system about them,

then the brain and nervous system

decide if the body needs to respond.

So if I touch something too hot, my nervous system

tells my hand to move away from it?

Exactly.

Wow.

I never knew my skin was so smart.

And it doesn't just feel hot or cold.

Your skin also detects other touches-- oh, like tickling.

Hey!

What are those things?

Those are your beautiful, your glorious, your fabulous sweat

and oil gland.

They keep you wonderfully sticky and sweaty.

Ew.

Yes, but a good ew.

Oil glands, or sebaceous glands, make

a sticky substance called sebum that moves up

to the epidermis, where it creates an oily layer that

protects and moistens your skin.

Sebum also makes your skin a little waterproof.

But what about the sweat glands?

Oh, I'm so glad you asked.

The sweat glands start here in the dermis,

where they make sweat that travels up--

Slowly, please.

[SIGH]

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--up to the epidermis, where the sweat comes out of holes called

pores.

And the last stop on the Skin Layer Express is the--

Subcutaneous fat.

A little warning next time maybe?

Ah, fat, sweet fat.

Why do we need fat?

The body needs some fat to cushion and help

protect your bones and organs.

This layer of fat also helps keep you nice and toasty warm.

Nice.

What else is down here?

See that thing over there?

I know what that is.

That's a hair follicle.

So the hair starts all the way down here?

And goes all the way up here!

Ugh.

I bet the hair does it at a more reasonable speed.

Oh, I forgot.

Near the base of the hair-- whoa!

Ugh.

--there are little muscles called erector pili that

tighten when you're cold and pull the hair so it stands up

straight.

It's called the pilomotor reflex.

(SINGING) Fancy word.

Ugh.

And that's what makes all those little bumps pop up

on your skin.

You mean goosebumps?

The very same.

Remember those blood vessels we saw on the dermis?

Yes.

These ones!

Yes, those ones.

When you're cold, they make themselves really small

to keep all your nice warm blood far away from the cold air

outside your skin.

Don't.

You.

Dare.

You were saying?

When you're hot, those blood vessels

bring all the blood closer to the surface of the skin

so it can cool down faster.

Is that why when I run a lot, my face gets red?

It is precisely why.

And the sweat glands help here too.

They produce a lot of sweat of the surface of your skin, which

evaporates and disappears, cooling you down

in the process.

Aah!

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Next time, I'm driving.

All right, you can drive in the sequel--

"Under the Surface of the Skin 2-- Chloe Takes the Lever."

Squee.

Now gimme some skin!

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