Importance of Skeletal System Video Lecture | Science for Grade 6

Believe it or not, there’s something a lot
like this inside of you and inside me, too!
It’s a skeleton!
You may have seen skeletons in a museum -- like
the ones they have of dinosaurs -- or maybe
plastic models of human skeletons, like this.
Maybe you’ve even seen dancing skeletons
around Halloween.
But do you know how important, and cool, and
powerful your skeleton really is?
Let’s get to know your bones
-- from how they help you move, to the different
kinds of bones you have, and even a super
special job they have to do!
Let’s get started!
One of a skeleton’s super important jobs
is, of course, to hold your body up!
Your muscles are strong, but they need a frame,
something to hold on to. Without a skeleton,
you’d be all loosey goosey, and you wouldn’t
be shaped like …you!
And it goes both ways! Without your muscles,
your skeleton would just be a pile of bones.
It’s only by squeezing and relaxing your
muscles that you’re able to move your bones
around.
So that silly dancing Halloween skeleton?
It’s just pretend -- because it doesn’t
have muscles!
So, your bones are hard enough to hold the
weight of the rest of your body.
But they’re also hard enough to act like
a protective shield around your soft, squishy
organs.
Your ribs, for example, are bones that protect
your lungs and heart so that even when you
get a great big bear hug, your insides don’t
get squeezed too!
And speaking of strong--the strongest bone
in your body is also the biggest, the longest
and the heaviest one you have.
It’s the bone that goes from your hip to
your knee, called the femur!
And that bone has to be big and strong -- because
when you run, jump, walk, or even just stand
still, a lot of the weight of your body falls
on the femur.
Now, where do you think your smallest
bone might be?
The very smallest bone you have is actually
in your ear.
This little bone, called the stapes,
looks kind of like a stirrup. Even in adults,
it’s only about the size of a grain of rice.
But this tiny bone has a big job. When sounds
enter your ear, they make this little bone
move back and forth. Those vibrations are
what your ears pick up as sound. So, without
this teeny bone, you wouldn’t be able to
hear.
Now I have a question, how many bones do you think we have?
Well … it kinda depends.
It sounds crazy, but you have fewer bones
now than when you were born!
Newborn babies have about 300 bones, but -- by
the time you’re finished growing -- you’ll
have only 206.
So, where did all those extra bones go?
Nowhere! As babies grow, some of their bones
grow together, or fuse, into one bigger bone.
For example ... your skull!
Your hard noggin is actually 21 bones that
are fused together, plus one bone that always
remains separate -- your jaw!
Your skull starts out as a bunch of separate
bones, because that leaves lots of room for
your brain to get bigger.
And once you’re fully grown, the fused parts
make an incredibly strong shield to protect
your precious brain.
One final fun fact about your skeleton? Your
bones … are alive!
Even though we often think of skeletons as
not living -- like the ones we see in a museum,
or in this model --your bones are full of
living cells.
Some of these cells are what make your bones
grow, and repair them if they get hurt.
And other cells -- which are tucked away in
a thick spongy layer deep inside your bones
-- have a very special job: They make your
blood.
That’s right! Most of the stuff that’s
in your blood is actually made inside of your
bones!
It’s because your bones are alive that they’re
able to grow -- like they are, in you, right
now! And they won’t be done until you’re
about 25 years old.
But even then, your bones will still be busy
holding you up, helping you hear, and making
your blood.
So bones in museums are cool, and Halloween
skeletons are fun -- don’t get me wrong.
But nothing’s more scary-powerful than your
own living skeleton and all the great stuff
it does for you!
Do you have a question about animals with
big bones, small bones, or no bones at all?
just let us know by getting help from a parent,
and leaving a comment below or emailing us
at kids@thescishow.com.
See you next time!