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Current time:0:00Total duration:10:12

Video transcript

when I first started thinking about this video I realized that asthma is going to be hard to talk about because so many people have it everybody knows at least a little bit about it so it might be hard to get really to the bottom of what really is asthma so to do this let's go all the way back from the beginning let's just start by talking about the lungs and what they look like and what they do so we have here your big trachea and they branch off into your left and right bronchi those are the two main stems of the lungs and from there they keep branching off like branches on a tree and then get smaller and smaller there are countless levels I'm going to just try to draw a few levels here for us so they keep branching off like this let it uh you get the idea then we inspire or when we breathe in inhaling it's kind of like a vacuum cleaner sucking air in and these are all the tubes that are connected to it so this is like the big hose if you can imagine your vacuum breaks down into little hoses that's basically what it looks like so in our lungs oxygen goes in when we breathe in Oh - is oxygen - oxygens and then on the reverse side when we breathe out we breathe out carbon dioxide which is the symbol of co2 one carbon and two oxygens now asthma is classified as an obstructive disease where air is a is blocked on the way out breathing out co2 but we'll get to that later exactly where that happens for now if we're just looking at the set of tubes otherwise known as our airway and anywhere we go if we take a cut like this across any of the tubes and we look at it up the tube or we look at what is called a cross section of it then it's going to look something like this so we have a round shape for the outside of the tube and then we have an opening and the in the middle here we call it the lumen the lumen is just the inside of any tube this is where air actually goes through and here in the walls of the airway we have connective tissue we have glands with all kinds of things but okay I want to talk about this smooth muscle layer here that's around in the wall of the airway so since it's a muscle that can have force and change the shape of things around it so in asthma we care about is that the smooth muscles can actually constrict this airway so to see what that looks like let me draw this again here again if this is the outside of the wall then a person who has active asthma happening at the moment their airway is going to be small the lumen is going to be smaller maybe about let's say this big and what has happened is that the smooth muscle around it is contracting hard and is clamping down on that lumen to make matters even worse when our body is inflamed it secretes fluid so into the lumen which is usually supposed to be open and dry we have extra fluid so when the opening is already smaller it's being flooded by mucus and fluid and this whole picture together is what asthma looks like in our Airways now I just showed you one tube here because we cut it once or here but imagine this process is happening in all these vacuum tubes all these little levels so the air is really having trouble moving actually if you can imagine a vacuum let me just draw one here this is the very primitive model of our vacuum and if you can imagine that this machine has a lot of power sucking air in but when it's coming out it's a passive process so there's no power pushing the air out so even though this constriction here will make it harder to suck air in but at least it has a motor behind it as opposed to when the air is coming out it just has to passively leave through the smaller straws so that makes it harder on the exhale we'll come back to what that sounds like when you listen with a sub scope but first let's talk about what causes this process why would your airway something clamp down like that why would our body allow it and what triggers it so I promise that every time I talk about lungs I will the first thing I will always say is smoking smoking can be a huge trigger for asthma doesn't have to be firsthand smoke it can be secondhand in fact kids who have asthma if they're exposed to parents who smoke in the house even parents who are smoking outside but then wear the same clothes inside the house that can trigger asthma because these smoke particles are billions billions of little things that don't belong the lungs and when they're in there this process can happen also because we live in a time where there's so much machinery around us this is a car you can tell so cars exhaust and pollution in general in the cities can be a huge trigger for asthma also people whose job to expose them to things like asbestos or other things that can inhale it can be a trigger and I'm just going to start writing because I can't draw fast enough we have paint remember that everybody has different triggers people who have asthma don't react the same way to the same things and this one I think is really sad some people can be triggered by food it can be allergic to foods or things in beer or wine can trigger asthma in some people now another trigger can be as common as stress our body reacts to stress in a variety of ways and can increase inflammation which asthma is basically an inflammatory process so this one I think is interesting a common drug that most of us are probably taken can be a trigger in up to 30% of adults we take this drug and that is aspirin helps with your headaches but sometimes causes your asthma to flare up and lastly babies who are completely different creatures from adults they can have GI reflux or what we call heartburn where the things in their stomach go back up the Safa goose isn't they're so small their systems they'll close together you can go up the esophagus and into the trachea so they can be triggered by GI reflux as you can see this which is almost every aspect of life this is probably why so many people have asthma and it's so different in everyone so going back to our kind of clinical medical way of thinking of asthma if you are going to listen to a person breathe through your skill set the scope this person has asthma what might that sound like you draw instead scope whew we're going to listen to these lungs now keep in mind as I said earlier there's a fluid in here as well so this smooth muscles constrict but there's also fluid and mucus getting secreted into these tubes as part of our body's way of dealing with inflammation so air and fluid together what do they form different air bubbles so as these air bubbles pop and reform and we're trying to breathe through them that's all when you listen we hear a high-pitched noise that's referred to as wheezing and wheezing is very characteristic of obstructive diseases like asthma wheezing basically sounds like a tiny little whistle so when they inhale and then exhale on the exhale you hear high-pitched noise all over the lung fields now I'm going to draw an imaginary line that divides our lung here so the trachea this is called the upper airway and down here are the smaller Airways and wheezing in asthma is a small airway disease and it's a small airway disease that happens on the expiration or when you breathe out now if there's noise on the inspiration that's usually caused by a foreign body or some other kind of process that makes the upper airway constrict that doesn't really happen with asthma unless it's super severe in this person is just dying for breath so usually asthma you can get an air in and it's on the expiration that we have a problem and you hear the wheezing because again the vacuum is sucking in air and the inspiration so it's going okay but when you breathe out passively the restriction really causes a problem so remember asthma wheezing small airway disease now this next part I don't have asthma so I always feel like I'm not such a good judge on what it really feels like to have asthma but we can imagine that if this person has trouble getting breathing out breathing out is just as important as breathing in if you can't do either it's a very scary process and this person coming in will be complaining of shortness of breath so shortness of breath sob is a very commonly used way to describe the symptom of can't catch your breath panting shortness of breath and depending on how severe their attack is at the moment a lot of people have rescue inhalers when they're panicking and can't breathe this rescue inhaler can deliver some emergency drugs to open up that airway and it's such an important intervention for people who have asthma to not only breathe but to feel like they can breathe to help with a panic and just a discomfort of not being able to get a breath in and out now lastly I just want to mention that asthma just from observation seems to be related to two other diseases there's as mother's eczema which is a disease of the skin you have excessively dry patches of skin that again flares up they can be red angry or dry and peely the skin disease and then third we have allergies or some people call it allergic rhinitis which is more proper for quickly involved your nose ryan itis but most people just call allergies and these three things for some reason seem to be good friends in that a person who has one is likely to have the other two we don't really know why we're still studying why that relationship exists but it does especially in children so this in a nutshell from a thousand miles above is what asthma looks like what it is so just a few key words to remember with airway constriction in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope