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.