How Your Muscles Work

How Your Muscles Work

Your muscles give you power to move and do important jobs in your body. Watch this movie for kids and find out more.

KidsHealth presents,
How the Body Works, 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.


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