So in this video we're going to be talking about
skeletal structure and then the function of those skeletons and specifically
human skeletons is what we're interested in
but before we talk about human skeletons let's talk about bug skeletons or the
skeletons of arthropods are insects
and so I'm going to draw a little ladybug here and our little ladybug
being an arthropod has what is called an exoskeleton and the XO and XO skeleton
actually first the fact that this skeleton is outside of the ladybug
so "exo" is actually Greek for outside or external humans on the other hand we are
vertebrates and as vertebrates we have this amazing network of bones located on
the interior of our bodies and so we have what are called endo skeletons and
endo is greek for within or inner referring to the location of the
skeleton is being inside of our bodies as opposed to outside now as humans our
endoskeleton performs a variety of pretty vital functions
the first of which is it supports our body and provides a framework for
movement
so what does this mean are our body is supported by the network of our bones
which allows us to sit up and stand and provide some sort of structure for our
body and then the limbs of our body in particular and various joints in our
body provide a framework for movement that allows you to run around to kick a
soccer ball to type on a keyboard
another important function of our skeleton is that it protects our most
vital organs
so if you look at the skull for example it houses our brain and the ribcage it
protects our heart and lungs and other organs and the third function of our
skeleton is
is that it performs a variety of physiological roles in our body namely
the storage of calcium and what is called hematopoeisis, which is the
production of all the cellular components within our blood
so our blood is made up of many different components plasma proteins
among other things and the cellular components of our blood which are red
blood cells white blood cells and platelets are all formed within the bone
marrow of my bones and so those are the main functions of the bones that form
our skeleton
now one way of classifying bones is differentiating between those that form
the axial skeleton and then those that form the appendicular skeleton
now the axial skeleton is made up of our skull and ribcage and our vertebral
column that is the axial skeleton it forms sort of the axis of our body right
right in the center down the midline and then the bones of the forelimbs and our
pelvis form what is called the appendicular skeleton and so
go are four appendages form the appendicular skeleton which is attached
to our central or axial skeleton another classification system for the bones in
our skeleton is the difference between flat bones and long bones
now what are flat bones some examples of flat bones are the bones that make up
your skull
the different bones that make up your ribs and then also the bones in your
pelvis and so flat bones really are describing the shape of the bone
these bones are made up of an inner spongy or cancellous bone and then the
outer shell is made up of compact bone
there's an inner spongy cancellous bone in an outer shell of compact bone and
flat bone serve primarily to protect our organs and serve as a site for him at 0
police's now long bones on the other hand some examples of those would be the
humerus in your upper arm or say the femur and your lower leg and if I draw a
long bone out here
there are a few different terms to be familiar with when you're referring to
different parts of the long bone the long middle portion of a long bone is
called the diathesis and then the end of a long bone is called the APIs and there
is the small area of bone in between the two are in the middle of the diathesis
and the purposes is called the metaphysis and the metathesis contains
the growth plate which is present
in the long bones of children and these long bones are made up of the same inner
spongy cancellous bone with an outer shell of compact bone just like flat
bones and these long bones really are the ones that provide a framework for
movement like we talked about before and they also serve as a side of hematopoiesis.
And speaking of hematopoiesi, where exactly does this Hematopoiesis
occur?
I mentioned that it occurs in bone marrow which is contained within bones
and there are two different types of bone marrow
there is what is called red bone marrow and then yellow bone marrow
now red bone marrow serves as the primary site for hematopoiesis, which
makes sense because the red blood cells from hematopoiesis actually make red
bone marrow look red to the naked eye
so you can remember that red bone marrows for blood or hematopoiesis
and you can typically find red bone marrow within flat bones and then in the
epiphyses of long bones. And then yellow bone marrow on the other hand is
primarily a site for fat storage made up of fat cells called adipocytes and
generally you can find yellow bone marrow within the diocese of long bones