00:00
Hi. Welcome to our video series
on neurological disorders.
00:05
In this video, we'll take a look
at multiple sclerosis.
00:09
Now, MS is a disease
where the patient's own immune system
attacks the myelin sheath,
or the cells that produce
and maintain the myelin sheath.
00:17
So, one easy way for you
to remember that
is MS stands for multiple sclerosis
and myelin sheath.
00:25
Multiple Sclerosis leads to scarring.
00:29
So, the inflammation
that the patient experiences
in their immune system
is attacking them.
00:33
They end up with inflammation
and injury to that sheath
and the nerve fibers.
00:38
Well, when this sheath
and the nerve fibers are damaged,
you end up with multiple areas of scarring
and impaired nerve impulse transmission.
00:47
In order for those nerve impulses
to move smoothly,
you have to have intact areas.
00:53
So because of the inflammation
and the scarring
that comes from multiple sclerosis,
now we have problems with those nerves
being able to be transmitted.
01:02
Now looking at the myelin sheath,
what really is that?
Well, in the central nervous system,
the myelin sheath is this protein.
01:12
It's this protein and fatty substance
that surrounds
and insulates the nerve fibers.
01:17
Now, they're very important.
01:20
It's what help keeps the system
running smoothly.
01:23
So, in your central nervous system,
that myelin sheath
is represented in our graphic
with that kind of blue-green color.
01:30
You see those little...
01:31
They almost look like pulled noodles
wrapped around that,
but think of that as the myelin sheath.
01:37
Now, the myelin is what helps
the transmission of the nerve impulses
along the axon.
01:41
We need that impulse
to move along the axon,
so the messages can be spread
from one to another.
01:48
So, you have myelin in the PNAS
or the CNS?
The answer is
myelin is present in both:
the central nervous system
and the peripheral nervous system.
01:59
Okay. Well, in the CNS,
myelin is produced by these cells.
02:02
Now, they're called oligodendrocytes.
02:05
That's a pretty big name.
02:06
But if you look in the drawing there,
you see those cells in the middle.
02:09
We've got them marked for you.
02:11
Those are the cells
in the central nervous system
that produce the myelin.
02:16
Now, over to the peripheral nervous system
or the PNS,
myelin is produced by the Schwann cells.
02:22
You can see it looks a little different,
but they both really help
the transmission.
02:27
Now, PNS and CNS myelin
are chemically different,
but they have the same function.
02:32
They promote the efficiency
of nerve impulse transmission
along the axon of the nerve cell.
02:37
So, multiple sclerosis
only affects the myelin
in the central nervous system.
02:44
So, it's present in both.
02:46
They do kind of the same thing,
but multiple sclerosis
definitely goes after the myelin
in the central nervous system.
02:53
Now, what happens
when you have these damages from MS?
Well, we know that it damages
and destroys the myelin
and the oligodendrocytes.
03:02
So, not only the sheath itself,
it also goes after the cells
that produce that sheath.
03:07
So, we have damage
to the underlying nerve fibers.
03:10
Now, when those fibers are damaged
with lesions and scars
along the nerve,
you can actually see those on an MRI.
03:18
So it's one of the exams
that a patient may have
to kind of look at where the status is
of their multiple sclerosis
or even in diagnosis.
03:26
So, because you have this damaged area
and these lesions along the line,
it's going to slow or really even stop
the nerve conduction in certain areas.
03:35
So now you have these neurological
signs and symptoms
that come from MS.
03:40
So, we're talking about multiple sclerosis.
03:42
We've got problems
with nerve transmission.
03:44
It's only in the central nervous system.
03:47
And because of this problem
with nerve transmission,
that's where the neurologic signs
that we see with MS come from.