Every cell in the
human body needs energy to survive and do its
different functions. If we're talking
about a brain cell, it needs energy to keep
stimulating other brain cells and sending on
signals and messages. If it's a muscle cell, it
needs energy to contract. They need energy just to do
the basic functions of a cell. And the place that they
get that energy from, or the primary source of
that energy, is from glucose. Glucose is a simple sugar. If you were to actually taste
glucose, it would taste sweet. And glucose gets delivered to
cells through the bloodstream. So this right here,
I'm drawing some blood that's passing by a cell. Maybe the blood is going in
that direction over there. And inside the blood, let
me draw some small glucose molecules passing by. And so in an ideal situation,
when a cell needs energy, glucose will enter the cell. Unfortunately, it's not that
simple for the great majority of cells in the human body. The glucose won't
enter by itself. It needs the assistance
of a hormone or a molecule called insulin. So let me label all of these. This right here is the
glucose, and it needs insulin. So let me draw insulin as
these magenta molecules right over here. That over there,
that is insulin. And the surface
of the cells, they have insulin receptors on them. And I'm just drawing very
simplified versions of them, kind of a place where these
magenta circles can attach, can bind. And what happens is, in
order for the glucose to be taken up by
the cell, insulin has to attach to
these receptors, which unlocks the channels
for glucose. In order for the
glucose to go in, insulin has to bind to
the insulin receptors. And then, once
that happens, then the glucose can be
taken up by the cell. Now, unfortunately, things
don't always work as planned. So let me draw a couple
of scenarios here. So, once again, let me draw my
very simple version of a cell and let me draw the bloodstream
going by right over here. And then let me draw the
glucose in the bloodstream. So I have my
glucose floating by, and then I have my
insulin receptors on the surface of a cell. Now, the first thing
that could go wrong here is what if the body
does not produce insulin? Insulin is produced
in the pancreas. What happens if the pancreas is
not producing insulin properly? So no insulin. Well, in this situation,
since there's nothing to bind to these receptors, the glucose
channels won't be opened up, and the glucose will not be
able to enter into the cell. And this situation
is type 1 diabetes, where you've got glucose. So in theory, you
have energy and you have properly-functioning
insulin receptors, but you just don't have
insulin to unlock the gates for the glucose--
for the glucose to actually go into the cell. The other scenario you
could imagine happening-- let me draw the cell again. So there is my cell
and let me draw the blood flowing past the cell. And once again, obviously,
this is just one of trillions of cells
in the human body. We have an estimated 10
to 100 trillion cells. So this is a very
simple diagram, but, hopefully, it
gets the point across. So once again, let me draw
some glucose floating by. Let me draw some insulin
receptors on the cell. Insulin receptor there, maybe
an insulin receptor right over there. And let's say we even
have some insulin. Our pancreas is producing
insulin and putting it into our bloodstream. So it's there to be used. But a situation can arise
where the receptors are not working properly or we become
insensitive or desensitized to insulin. So in this situation--
sometimes maybe it might be the insulin is hard to
bind or, even if it does bind, it's not working properly. So the glucose will
not enter the cell. I already wrote desensitized. So in either one of
these scenarios-- let's just think in
a very broad level. I'm not going to go into the
details of the actual therapy for these diseases of
how it can be cured. Oh, and I didn't even
name the second one. The second one right
here, as you can imagine, if this up here is
type 1 diabetes, this down here is
type 2 diabetes. The simple way
that-- I don't want to say that it's
necessarily simple, but the way that you could
manage type 1 diabetes is you can inject insulin. The only problem
here-- it's a big one, though, is that there's no
insulin in the bloodstream. Everything else is
working properly. So over here, we
can inject insulin. And then you'll have insulin
to attach to the receptors, and then the glucose can
be processed properly. Type 2 diabetes-- there's
multiple lines of attack. One thing that
you can do-- there are actually drugs that attempt
to re-sensitize your insulin receptors. You can also do that with
a combination of lifestyle changes that makes
your body, I guess, more sensitized to sugar. Or you can even-- if
things get severe enough, you can add insulin,
just like you would do in type 1 diabetes. And you can say, wait, I
already have insulin here. Why would I add more insulin? Well, remember, the cells
can process insulin, but they're desensitized. They would need more
insulin in order to uptake the same
amount of glucose. So if you add insulin,
you could possibly have enough of a trigger
that the glucose can actually be taken up. But there's multiple
lines of attack here, and usually the
first one are giving drugs that help, hopefully,
re-sensitize or make you less desensitized
to the actual insulin. So the last thing I just want
to think about a little bit is-- well, what happens
if you didn't do this. Well, there's two
major problems here. Obviously, your
cells can't function if it's not taking up glucose. So your cells will
have no energy. And another problem--
if you weren't to manage either
one of these types of diabetes, is
that sugar, if it gets to high enough
concentrations in the blood, it can actually cause
a lot of damage. Sugar can cause
damage to the body. So you don't want either
of these things happening. You want your cells
to have energy, and you don't want to
have too much sugar flowing in your blood and
causing damage to your body.