Hyperplasia is increase
in cell number.
As a result of that, the organ
will also clearly increase in size.
I want to distinguish it from hypertrophy,
which just means an increase in cell size.
This is cell number.
Okay, so hyperplasia.
It is reversible.
And a good example,
so you increase the cell number,
and then at the end of the period of time,
when you don't want that
cell number anymore,
you have those cells
You have them die,
in a controlled way.
And then you get back to normal so
good example, it's cycling endometrium.
We build up a very lush and
demetrial surface up to 5 millimeters
over the course
of a normal cycle.
And then at the end of
the menstrual cycle,
that will revert back
down to .5 millimeters.
And you go that over
and over and over again.
It's an increase in cell number.
And what's actually
shown on the slide here,
is a very good example
of lactational breast.
On the upper panel is a breast of
a pre-pregnant, nonpregnant woman,
and you concede the
blue are glands.
Nine months of estrogen and
progesterone have given rise
to many, many, many more glands.
And that will be the lactational breast
that will be able to support nianate.
As a result of that, there has been
an increase in the breast size,
and that is again reversible.
Soon as the woman is no longer
lactating, hormonal stimulation goes away
and those cells undergo a programmed
cell death until we revert back
to what we have on top.