Bones are made of proteins and minerals
and are amazingly strong enough to support the entire weight of your
body. If you cut a bone and look at the inside you will notice that
bones are not solid, but essentially hollow. This allows for a pathway
of blood vessels to bring nutrients in and out. There is a
mesh-like structure inside of a bone and this is called the marrow. If
you were to take a microscopic look at the bone marrow of a human, you
would find lots and lots of blood cells. One of the functions of bone
marrow is the production of blood cells. At different times during
your growth, blood was made in various locations within the
skeletal system. But as you get older,
the majority of cells are made in the long bones of your body and
in your pelvis.
Cross Section of a bone.
Photomicrograph of bone marrow.