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Current time:0:00Total duration:7:13

Video transcript

let's talk about exactly how flu causes so much damage to our cells and why it makes us feel so lousy whenever we get the flu I'm going to start out by drawing the flu virus here this is our influenza virus influenza virus and we have on influenza a couple of couple of features we have to remember so you know on the outside there's this little envelope and what's on the inside of this envelope are eight bits of RNA eight pieces of RNA and so this RNA is important to remember because in the human cell and our cells I'm going to draw one of our cells right here we have instead of RNA we have DNA remember and so this is our nucleus and on the inside of our nucleus is our DNA so this is our DNA over here so the virus has RNA and we have DNA and the outside of the human cell actually let me label this over here this is human cell the outside of the human cell has something called silac acid there are these little strands over here they're coming off I'm drawing them far larger than they are in real life they're not nearly this big but there are these little tiny little things called silac acid and this silac acid becomes very important in understanding how the influenza virus gets into and out of our cells so on the outside remember of the influenza virus there were a couple of proteins and I'm going to draw one of these proteins here and I'm going to make it look like a hand so this is a little hand and this protein is called hemagglutinin in fact previously I'd called it the H protein and you can call that if you want but the full name is hemagglutinin hemagglutinin and what hemagglutinin does is that it actually holds on to silac acid in fact that's an easy way to remember it right because h and h go together it holds silac acid and that becomes very important because that allows it the first step towards getting into the cell now there's another protein on the outside here I'm going to make it look like a pair of scissors because I will kind of remind what this one does and this is called neuraminidase so this one is called neuraminidase neuraminidase and I'm going to neuraminidase and I'm going to pass on explaining what it does just for the moment I'll tell you in a little bit what it does so then the first step to get into the cell is for hemagglutinin to hold on silac acid and then there are a few other small molecular steps that happen important ones but I'm going to suffice to say it gets inside and once the influenza virus gets inside these RNA segments they are let loose so these segments are going to start making their way towards the nucleus and so once they get into the nucleus they're in that same kind of area that the DNA is and what they do is remarkable that basically they take over these little rnas start making many copies of themselves and what they want to do is make our human cell into a factory they want to make a factory in this Factory is going to make little proteins viral proteins and it's going to make viral RNA and what it's not going to do the one thing that the cell is no longer going to be very good at doing is its normal job so the human cell of course had some job to do and it's not going to have the resources or the time to do it because it's basically being taken over by this viral RNA so what happens then is that the vinyl RNA is basically turn it into a factory and what it wants to do is make more and more copies of itself so let me actually just show you what that would look like here's a daughter cell let's say it goes over here and I'm going to clean this up a little bit just to make sure that we're looking at a nice neat picture let's say something like this so this is our daughter cell on the other side and these cells are going to try to make their way out of the human cell right because now they're packaged they're ready to go and where do you suppose they want to go next where they're going to want to find their own human cell to invade because they want to continue this process so we've got more human cells over here down below we've got maybe let's say one human cell up here we've got new targets for this virus and this virus is going to seek out these targets and try to make its way inside again using its hemagglutinin but before it can do that it's got to break loose right because it's still attached to that sciatic acid and so here's where neuraminidase comes in the neuraminidase it basically it Nix and there's where the N is helpful for remembering it it mix or cuts silac acid and so if we can Nick or cut that silac acid it can break free and so I remember the two proteins as hemagglutinin hold silac acid to enter the cell that's on entry and the neuraminidase is going to Nick this alyc acid and that's important for exiting the cell but we still haven't answered the question how does all this cause our symptoms well what happens is that as these cells get turned into factories they start dying or getting damaged and all their contents start leaking out so all these contents from the cells start leaking out and as they do they create inflammation let me bring up a little bit of canvas if you have inflammation let's say that inflammation is happening in your nose well you might say well I have a runny nose or a stuffy nose or if that inflammation is happening in your throat you might say well I have a sore throat might hurt and if it's happening in your lungs you might have a cough so a lot of those respiratory symptoms remember we had two categories a lot of those respiratory symptoms I'm going to shorten as resp those are going to be explained by inflammation or at least in part by inflammation and remember there's also constitutional symptoms right with constitutional symptoms those were things like having a fever or having fatigue and the reason for that is that your immune system is going wild and crazy when you have influenza it's going to be attracted to all of those chemicals we call these cytokines that are being released and it's going to be attracted to the fact that you've got actual virus particle in the area you know that's being infected so that strong immune system is going to create some of your symptoms it's actually going to rev up your temperature and you'll you'll start having a fever or chills and because all your energy is being spent on this this attack you're going to be fatigued you're going to be fighting off the virus and so you're going to be fatigued you might have body aches so a lot of these kinds of symptoms you get as a result of a strong immune response