Suppose a machine had to be built
which had to grow for 20 years,
without shut-downs, or
maintenance, or repairs. This
would be like buying a small car
and using it while it became a
large family car, or a bus!
Bones can do this.
Bones can grow, maintain themselves, repair themselves and adjust to the daily stresses for more that twenty years.
The human body, which comprises of trillions of
cells, grows steadily
from conception. Every cell,
though an individual, is regulated to grow
or die in relation to all the others. Muscles, veins and arteries, for
example, grow at different speeds to match bone growth. When one
considers
this feat of coordination, it is utterly amazing.
OSTEBLASTS build new bone cell by cell.
OSTEOCLAST destroy bone, cell by cell.
ew bone is usually produced near the outside surface,
while at the same
time bone disappears from the inside
cavity. This means bones are
always being modelled
and remodelled all the time. It is not static,
but alive, and mobile. The cells which do this repair and maintenance
work are called OSTEOBLASTS and OSTEOCLASTS.
At any give moment, our bones
are in a state of repair and destruction. This process is essential,
especially when our bones are damaged, because without the coming and
going of bone cells, our bodies would not be able to grow. It also helps
us adjust to an increase in stress. If we
carry heavy loads day after day, our
bones grow thicker to adjust to the
extra load.
