Multiple Sclerosis: Definition and Causes (Nursing)

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.