Hey, scientist, check it out! I went to the doctor recently to get an X-ray of
my arm. Have you ever had to get an X-ray before? An X-ray is a machine that is able
to take a special picture that lets doctors see inside your body. That got me wondering,
what is inside my body? All week, I've been working on my own machine that will let us see
inside the human body. I think it's almost... Yes! Done. Do you think we should try it out? Come on, let's go.
Alright, just have to press a few buttons and... Whoa! This looks an awful lot like my X-ray.
But look! I have these things all over my body. What do you think they are, scientist? That's
right, bones. Did you know humans have over 200 bones in their bodies? When all of the
bones are put together, it's called a skeleton. Our skeleton helps us to do so many things. It
keeps us upright, helps us move, and protects the other parts we have inside our bodies. The bones in
our skeleton come in all shapes and sizes. In the fingers, there are lots of tiny bones. In the leg,
the bones are much bigger, and there aren't as many. If you press in your skin, you may be able
to feel some of your bones. These curved bones are ribs, and they work like a cage to hold and
protect a lot of different body parts under there. Oh, and these tiny bones stacked all the way down
the middle of the body are called the spine, or the backbone. The spine not only holds the
body upright, it also is the pathway that sends messages from the brain all over the body, telling
it what to do and feel. Speaking of the brain, let me put on my special hat. Here. And aha! There it
is. The brain is located in the head, protected underneath a set of bones that make up the skull.
It's important that the brain is protected because it does so many things for us. You probably
already know that we use our brains to think, but did you know that your brain also controls
movements? Anytime you kick a ball or wave to your friend or chew on a sandwich, your brain is
telling those different body parts to move. Have you ever accidentally touched something hot and
quickly pulled your hand away? That was your body sending signals to your brain of how it felt, and
your brain telling your body to respond. Phew! Thanks for keeping me safe, brain. There are also parts
of our bodies that the brain controls without us even having to think about them, like our beating
hearts. Speaking of, let's check out the heart. It's one of those body parts protected by the
ribs. And... yep! Here it is. What does the heart do for us? Well, a lot, actually. The heart
has little rooms or chambers that hold the body's blood inside of them. Our blood holds the oxygen
and nutrients that the body needs. Every time your heart beats, blood is being squeezed out
of the chambers and sent all around your body. Without our heart pumping blood, we wouldn't
be able to give our body what it needs to stay healthy, protect itself, or heal. Doctors often
use a tool called a stethoscope to listen to a patient's heart, but you don't need a stethoscope
to feel your heart beating. You can actually feel your heartbeat in your wrist. That's right,
every time your heart pumps blood, you can feel your blood pulse right here. If you can, hold up
the first two fingers on your hand, like this. Now, place them gently on the wrist of your opposite
hand, right under your thumb. Keep still and pay attention. Do you feel a pulse? That feeling in
your wrist is telling you each time your heart is contracting, or squeezing out blood. Pretty cool,
huh? Our hearts are able to contract because they're actually made out of muscle. If you're
thinking, but aren't muscles the strong part of your arm? The answer is yes. The heart is called
a cardiac muscle, and it's one of the muscles in our bodies that move without our brain having to
think about it. We call it an involuntary muscle. But most of your muscles are actually attached
to your bones on the inside of your body. These muscles are called skeletal muscles because they
work with your skeleton, and they're voluntary muscles because our brain needs to tell them when
to move. They work by pulling on the bones to move them back and forth, which is why humans are able
to do so many cool things, like running and jumping and even smiling. What about things you do all the
time, like breathing? Do you think breathing is a voluntary or involuntary action? Guess what,
it's both. When you're focusing on your breathing, like when doing yoga, singing, or swimming,
you are breathing voluntarily. But, when you aren't focused on it, like when you're sleeping,
breathing still occurs involuntarily because breathing helps to keep our bodies alive. The
lungs have two jobs. The first is to take the air we breathe in and give the oxygen to our blood so
it can be delivered to all of the parts of our body. The second job is to take the waste out
of our blood and release it from the body in the form of carbon dioxide as we breathe out. I -- What's
that sound? [Stomach growling] Oh, I know. Do you know what this body part is called? That's right, the stomach.
The stomach is where the food we eat goes to be broken down into nutrients the body needs. The
stomach produces juices, called stomach acid, that mixes with food and breaks it down into nutrients
and waste. The nutrients are then sent along to be absorbed by the body, and the waste continues
on to be released from the body. So, the gurgling sound coming from my stomach is a signal that my
body wants more nutrients. I guess I ought to get something to eat so I can stay healthy and
strong. So, scientist, today we learned about some of the parts that can be
found inside the human body: our bones and muscles, brain, heart, stomach, and lungs
all work together to help us perform everyday activities, like eating this
apple here! So the next time you sing along to your favorite song, take a bite of food,
or play outside with your friends, just think about all the incredible things that your body
can do for you. Remember, science is all around you, and, it's a part of you too.