with Chloe and the Nurb.

Chloe, look.

What's this?

My best friend Wally.

He's coming to visit.

We've been writing each other for years,

and he's finally coming.

He should be here any second.

How do I look?

How do I look?

I think you look gre--

No time for this.

I've got so much to prepare.

So much to prepare!

What's that over there leaning on that tree?

Someone left a plank of wood against this tree.

I hate litterbugs.

Wally!

Oh, Wally, how fantastic it is to see you.

Um?

how was your trip?

Hm?

Oh, man.

oh, oh, so true.

You've still got it, Wally.

Oh, let me introduce you to someone.

This is my very good friend Chloe.

Seriously?

Um.

Hi there, Wally.

Pleasure to meet you?

Oh, Wally, you must be exhausted from your travels

I can only assume you want to rest, and what's that?

You want a tour?

Oh, no problem.

Chloe will be happy to carry you.

I'm not carrying that thing.

You carry it.

What my buddy, Chloe, was trying to say

is we would love to show you around.

Yes.

Yes, I would be happy to take you

on a tour of Bodylandia, Wally.

If you look to your left, you'll see an ear floating

majestically in the sky.

Nurb, Wally's heavy.

My muscles are working hard here.

You're holding Wally with your skeletal muscles, which are

also called voluntary muscles.

You can flex those muscles and move them

when you want to for walking, running, swimming--

Carrying around your wooden friend.

Smiling, tying your shoes, focusing your eyes,

writing your name, or waving to a friend.

Hi, friend.

Are you OK, Chloe?

Oh.

Great.

And on with the tour of Bodylandia.

Wait.

Nurb, instead of me caring around your super heavy friend,

why don't we stay here, and you can tell me more about muscles.

Hm.

I see what you're trying to do here.

You're trying to give our friend, Wally,

some valuable knowledge.

Well done.

[SIGH]

Wally, a person has more than 600 muscles

in all shapes and sizes, and they all have different jobs.

Skeletal muscles are just one type

though they're probably the kind you

think of when you think of muscles,

because skeletal muscles give your body power and strength.

Skeletal muscles are attached to one end of a bone and stretch

across the joint, the place where

two bones meet, and attach to the bone on the other side.

The muscles then move your body parts

by contracting and relaxing.

They work in pairs called flexors and extensors.

In your arm, the bicep muscle is a flexor

and contracts to bend your arm at the elbow, which is a joint.

The tricep muscle is an extensor and contracts

to straighten the arm.

Any questions, Wally?

What other kind of muscles are there?

I'm so glad you asked.

Your other types of muscles are your cardiac and smooth

muscles, which are both involuntary muscles.

That mean they move on their own,

without you having to think about them.

Cardiac muscles keep your heart beating,

and smooth muscle is found in your stomach, intestines,

and bladder.

Any more questions?

Nope?

Oh, great.

On with the tour.

Wait.

I have a question.

Yes, Chloe?

Um, how do you-- how do my muscles get the message

that it's time to move?

Chloe, that question is excellent.

When you decide to move, your brain

sends a message through the spinal cord

to the nerves, the nerves contract

the muscle you want to move.

Then sensors in the muscles send messages back to the brain,

and the result is smooth, coordinated movement.

Pretty neat, eh, Wally?

Oh, why so sad?

What did I say?

Oh, Wally, you don't need big weightlifter muscles

to be strong.

There are plenty of ways to build strong muscles,

like playing sports, crossing the monkey

bars at the playground, eating a nutritious, balanced diet.

Protein is especially important, and can

be found in foods, like meat, eggs, peanut butter, and tofu.

Well, that's enough touring and learning for one day.

Let's all relax.

Thank goodness.

By playing a game.

Oh, no.

Don't worry, Chloe, since you used your muscles

to carry Wally around all day, you get to pick the game.

Just pick something we can all play together.

Hm.

I've got it.

Ping-pong, my favorite, and Wally's.

Thanks for lending a hand, Wally.

What's that?

Wally just said, I'm the best player he's ever seen.

Oh, Wally, you're such a charmer.