BONES, WHO NEEDS THEM?...................
(YOU DO!)
What
would happen if humans didn't have bones?
You'd be floppy like a beanbag. Could you stand up? Forget it. Could
you walk? No way. Without bones you'd be just a puddle of skin and guts
on the floor.
Bones have two purposes.
Some, like your backbone, provide the structure which enables
you to stand erect instead of lying like a puddle on the floor.
Other bones protect the delicate, and sometimes
soft, insides of your body. Your skull, a series of
fused bones,
acts
like a hard protective helmet for your brain. The bones, or
vertebrae,
of your spinal column surround your spinal cord, a complex
bundle of
nerves. Imagine what could happen to your heart and lungs without the
protective armor of your rib cage!
How
many bones do humans have?
When you were born you had over 300 bones. As you
grew, some of these bones began to fuse together. The result? An adult
has only 206
bones!
How
do my bones move?
With a lot of help. You need muscles to pull on bones so that you can
move. Along with muscles and joints, bones are responsible for you
being able to move. Your muscles are attached to bones. When muscles
contract, the bones to which they are attached act as levers and cause
various body parts to move.
You also need joints which provide flexible connections between these
bones. Your body has different kinds of joints. Some, such as those in
your knees, work like door hinges, enabling you to move back and forth.
Those in your neck enable bones to pivot so you can turn your head.
Still other joints like the shoulder enable you to move your arms 360
degrees like a shower head.
Are
your bones alive?
Absolutely. Bones are made of a mix of hard stuff that gives them
strength and tons of living cells which help them grow and repair
themselves. Like other cells in your body, the bone cells rely on blood
to keep them alive. Blood brings them food and oxygen and takes away
waste.
If bones weren't made of living cells, things like broken toes or arms
would never mend. But don't worry, they do. That's because your bone
cells are busy growing and multiplying to repair the break! How? When
you break your toe, blood clots form to close up the space between the
broken segments. Then your body mobilizes bone cells to deposit more of
the hard stuff to bridge the break.
What's bone marrow?
Many bones are hollow. Their hollowness makes bones strong and light.
It's in the center of many bones that bone marrow makes new red and
white blood cells. Red blood cells ensure that oxygen
is distributed to
all parts of your body and white blood cells ensure you are able to
fight germs and disease. Who would have thought that bones make
blood!?!
Do
all critters have a backbone?
Nope. In fact, some 97% of critters on earth don't
have a backbone or spine. Remarkably enough, of those that do have a
backbone, there are lots of similarities: a skull surrounding a brain,
a rib cage surrounding a heart, and a jawbone or mouth opening.
Factoids
The human hand has 27 bones;
your face has 14!
The longest bone in your body? Your thigh bone, the femur --
it's about 1/4 of your height. The smallest is the stirrup bone in the
ear which can measure 1/10 of an inch.
Did you know that humans and giraffes have the same number of
bones in their necks? Giraffe neck vertebrae are just
much, much
longer!
You have over 230 moveable and semi-moveable joints in your
body.
What
would happen if humans didn't have bones? 
a series of
fused bones,
acts
like a hard protective helmet for your brain
. The bones, or
vertebrae,
of your spinal column surround your 
spinal cord, a complex
bundle of
nerves. Imagine what could happen to your heart and lungs without the
protective armor of your rib cage
! 
Red blood cells ensure that oxygen
is distributed to
all parts of your body and white blood cells ensure you are able to
fight germs and disease. Who would have thought that bones make
blood!?! 
has 27 bones;
your face has 14! 
Giraffe neck vertebrae are just
much, much
longer! 
