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0:00
Osteoclasts are among the most
remarkable cells in the body.
In this lecture, in
addition to outlining
their key regulatory pathways,
I want to address some aspects
of osteoclast biology that
might be less well known,
with a special focus on the roles of
the fundamental parameters, oxygen
tension, and pH.
0:22
If you want to see osteoclasts
in action, a good place to start
is actually to look at erupting
teeth in the developing jaw.
In this image, you can see
adult teeth embedded in the jaw,
and milk teeth protruding
from the gum above.
The developing adult teeth that
are embedded in the jawbone
have to make their way
through the jawbone
in order to erupt and
serve their function.
0:48
This image shows, in higher power,
the developing, erupting adult
tooth surrounded by
the concave bone.
Lining the bone, you can
see a number of large cells
is the osteoclast.
And these are in the process of
eroding away the bone of the jaw,
the alveolar bone, in order
to make way for the tooth.
1:11
At higher power, we see the row of
osteoclasts on the bone's surface.
And we see that each
osteoclast is embedded
in a concavity in the bone.
This is the process
of bone resorption.
In juveniles, such as the
specimen we're seeing here,
osteoclasts may be quite frequent.
1:34
However, in adult bone, osteoclasts
occur far less commonly.
But, for example, if we look at
this section of a human finger bone,
there's only a very small
area, highlighted here,
in which osteoclast
activity is evident.
