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Current time:0:00Total duration:7:10

Video transcript

okay so let's say you have some kind of letter that you wanted that you want to deliver right so you have a letter that's in your mailbox and let's say that this is the the sender of the letter right and so the sender of that letter is going to deliver that mail all the way over here to the recipient right and the way that they're going to do that is you're going to have this this mailman and in this truck deliver it from you know from the sender to the recipient and they're going to drive along this road but then let's say something happens let's say for some reason an earthquake happens right and the earthquake actually destroys the road over here and so now the mailman can't really get to where they need to go anymore right because the road has been damaged so why am I giving this extremely hypothetical scenario well I think that it serves as a pretty good analogy towards understanding a disease called multiple sclerosis so multiple sclerosis is a disease of the brain and more specifically it affects the communication within the brain so what do I mean by communication in the brain well in the brain you have all these neurons right you have all these in your arms that are constantly talking to each other kind of like these two neurons over here and so this neuron is going to send an electrical signal down the length of a D axon and that electrical signal is in the form of an action potential and so to improve the efficiency of the communication you have this stuff that kind of insulates the axon so the stuff that I've drawn here in red is called myelin and it really just makes the the action potential move down the axon much more quickly so we can actually kind of compare this to a communication system right with our mailman so you know we have kind of the sender of the message that would be the first neuron we have the message that would be kind of like the action potential we have the road which would be you know the the myelin and the axon together and we have the recipient now in our analogy we had an earthquake that actually destroyed the road somehow so in multiple sclerosis what happens is you all you get destruction of the road and more specifically you get a degradation of the myelin and so because there's degradation of the myelin we can call multiple sclerosis a demyelinating disease so this is really where that disruption in the communication goes on right and when the myelin is degraded the action potential won't really travel down the axon as quickly anymore and sometimes they may not even travel down to begin with so what's causing that degradation well as it turns out in multiple sclerosis the immune system actually sneaks its way into the brain and when the immune system sneaks its way into the brain for some reason it mistakenly recognizes that myelin right this myelin over here as as foreign and when it mistakenly recognizes it as four and it starts to attack the myelin hence this degradation and because the immune system is attacking the body itself we call multiple sclerosis and autoimmune disease as well so that's kind of a cellular perspective on multiple sclerosis but now I kind of want to give you a more more macroscopic perspective on the one what the disease does to the brain right so let me clear up some space over here and let me actually show you now two different brains so this is just really a brain scan or two different brain scans of well two different brains so on the Left we have a perfectly healthy brain and on the right we have the brain of someone who's suffering from multiple sclerosis immediately on the right brain you can tell that you have these bright spots over here right called plaques so plaque is also really referred to as a lesion and a lesion is really just a piece of tissue that's been damaged so let's say for example you know you have a hand over here now maybe you get a cut on your hand somehow right you can call that cut kind of a lesion of the skin in multiple sclerosis you have a lesion in the brain Randle's those lesions are really coming from the damaged myelin from the immune system so what happens is you have all these immune cells that kind of come together right they kind of cluster around certain parts of the brain and they attack it and when you have a whole bunch of immune cells coming together to attack a certain part of the body we call this inflammation and because it's happening in the brain we call it neuro inflammation now the condition in which you have these lesions in the brain is called sclerosis in the case of multiple sclerosis you have multiple lesion hence why we call it multiple sclerosis now notice how you're getting these lesions in different parts of the brain okay different parts of the brain are going to be responsible for different functions some may be responsible for vision others may be responsible for for a cognition for moving around or movement or touch and so on and so forth and depending on where these legions form in the brain you can get a variety of different symptoms that can affect all of these functions now why do these legions form why does the immune system attack the brain the problem is that we don't actually know we're not really sure with 100% certainty what causes multiple sclerosis all we know is that some people may have some a kind of genetic predisposition towards developing the disease and that there are also probably some environmental factors that may be involved as well and and the the fact of the matter is that your genetics can really interact with the environment and that can kind of stimulate the progression of the disease now the exact types of genes that are involved on the exact types of environmental factors that may be involved will be a top that I'll cover in a later video but for now this is really all that we know about the causes of multiple sclerosis now even though we don't really know perfectly what causes multiple sclerosis we do know who is more likely to develop the disease so I'm going to actually clear up some more space here again it's not going to show you a picture of the earth the reason is because I want to give you a global perspective on you know the prevalence and the incidence of multiple sclerosis so the disease affects about two and a half million people worldwide now is everyone on the plan evilly likely to develop the disease well no as it turns out if you move north from the equator right so if you move north from here you'll notice that the incidence of MS actually increases and the incidence is actually pretty high you know in these northern areas right so like here in Canada and the northern United States and here in a lot of Europe and Russia as well so it often affects Caucasians more than other races and more specifically among the Caucasians it affects people of Northern European descent more often the disease is also more common in women than it is in men right it's thought that of the two point two and a half million people worldwide about two-thirds of them are women so 66% of them are women so what age do people start to develop ms it's usually in the age range of 20 to 50 years old and it's usually on the earlier end of that spectrum and lastly one thing that I really want to emphasize is that the disease itself is not fatal so the disease itself won't actually kill you right but the life expectancy is a bit lower and sought to be lowered by about you know a few months to a few years now even though it's not fatal the disease itself is quite debilitating and it can really affect the person's lifestyle through a number of different signs and symptoms and that will be a topic that I'll cover in the next video