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Studying for a test? Prepare with these 15 lessons on Circulatory system diseases.
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Video transcript
Voiceover: So we're looking at a very interesting building that has two rooms that are separated by this interesting hallway in between. We have some people that are entering into room number one. And these people are entering into room number one, they're trying to get to room number two. So what they're going to do is go via this hallway. And then they have a number of options. They can take this smaller hallway, here, or they can take this one here. And they can take this one here. So they have a number of options. The beautiful thing about this hallway is that there are tables there with food and snacks and hors d'oeuvres and all kinds of interesting things that they can eat. And then they can continue on. So these people in this reddish color, they're going to be the satisfied people. They've filled their stomachs and they are good to go, they're going to continue on into room number two and then they can continue on about their business to do the things that they're supposed to do. Now, what will happen is, in this situation, if there's a lot of pressure in that room, that will cause people, if there's an opening here, it can cause some of the people to start going back through this little channel here to get back into room number one. And then they're going to start moving into, once again, this hallway. Then you can see, it's going to start to get a little congested in here. It's going to get a little tight and that just make things a little awkward, right? So you have these people that are coming through once again going through this cycle so that they can, then, get back to room number two where they were before. And when they start getting congested in here, they're going to start getting congested farther back and then even in room number one. Well, that's exactly what we see in certain individuals that have non-cyanotic heart disease. With non-cyanotic heart disease, we're talking about a congenital disorder ... And congenital just means that individual was born with it. What that's going to result in is, like in this case, we have a hole in the wall between the right ventricle and the left. And the result is going to be that blood, and these are our people, the blood is going to flow from room two to room one. From the left to the right ventricle. But what is supposed to happen, just like what we saw before, was people are entering via room one, they're doing what they're supposed to do and then those people are going to leave. And here we see them leaving via these structures that we call the pulmonary arteries. And they're going to go to our lungs and then they're going through these little hallways and those little hallways are our pulmonary capillaries. And these are exciting too. This is exciting too because along the way, they're going to pick up some food. But the food in this case is oxygen. So now they're picking up oxygen and you can see these guys are satisfied and they can continue on and go via room two, like we saw before with the previous example, and via room two they can then leave and go throughout the body to deliver that oxygen to all of the tissues that need it. But in this case, we have this little defect that causes blood to flow from the left side to the right side because you have significantly higher pressure on this left side then you have on the right. And then that, like we saw with the previous example, is going to cause these guys to continue on here and that can result in a type of congestion. And that type of congestion we are going to call pulmonary ... Pulmonary congestion. And that pulmonary congestion is just like we saw before, but it's going to be in your capillaries, your pulmonary capillaries. And that increase in pressure can actually cause damage to these pulmonary capillaries and if you cause damage to the pulmonary capillaries, that's going to cause even more pressure because it's harder to get it through, to get the blood through these damaged capillaries. That's going to feed back, you're going to have increased pressure here because there's so many blood cells trying to get through, and that can feed back to room one which, in this case, is your right ventricle. All right? So we have, basically what's happening is, we have an increase in pulmonary ... Pulmonary pressure, and that's basically the pressure in the lungs, in the capillaries that are throughout the lungs, the blood vessels in the lungs. And that is going to cause ... So let's draw an arrow pointing here. That increase in pulmonary pressure is going to cause an increase in the pressure in the right heart. So the pressure in the right heart is going to increase and that can increase significantly. Now, we said that we had that situation here where we're having blood flowing from left to right. But what happens if you continue to get more congestion and more increase in pressure here and that pressure feeds back to the right ventricle? Well what's going to happen is, if the pressure over here gets greater than on the left side, what can can happen is you end up with a reversal where the blood is now flowing from right to left. And that is what we're going to call Eisenmenger syndrome. Eisenmenger syndrome. So that is something that happens as a result in the buildup of pressure that results in the blood moving or shunting ... Like you're squeezing that blood through that opening and it's going from right to left. Now what are we going to see as a result of that? Well, there's a few things. The blood that we have on the right side, what kind of blood is it? Well, it's going to be de-oxygenated blood. So now we're going to have de-oxygenated blood bypassing the lungs and that getting into the bloodstream that's going throughout the body. And that's never a good thing because the tissues, the organs, everything needs oxygen. So we're going to have a decrease in oxygen throughout the body. And as a result of that, we're going to get a decrease in function. All of the cells throughout the body need oxygen and if the oxygen levels start decreasing, that is going to cause them to not function as well as they should. One of the ways that we do see this is with a sign that we call cyanosis. Cyanosis. And what happens here is, basically, you know you have this de-oxygenated blood, in this case, that's going throughout the body and that de-oxygenated blood is going to be darker. And when it goes through the skin ... When you're looking at your skin, let's say this is someone's hand and you look at the skin, it's going to give it kind of a bluish color. So it's going to look a little bluish because of how the light is being reflected. So it's going to give the skin a bluish color. This is a very bad illustration of skin but you get the point. All right, so cyanosis is something that we see. Let's continue on with this blood vessel. So we're going to look at just one blood vessel that is going to be traveling throughout the body. And we're going to have our red blood cells that are traveling throughout and these red blood cells are the ones that are responsible for carrying the oxygen through the body. And let's say, what we're looking at here is a normal concentration of red blood cells. If you're not getting enough oxygen, the body is going to say, "Hey we need "to get more oxygen. So what we're going to do "is we're going to produce significantly "more red blood cells." And that is called polycythemia. Polycythemia. And you can imagine how that can cause problems. Because if you have significantly more red blood cells, then the blood is going to be thicker. And as that thicker blood is going through the lungs, it can cause even more congestion and even more of an increase in pressure. And one of the last signs that we see in individuals with Eisenmenger syndrome is what we call clubbing of the fingers. So I'm going to draw a hand over here. Actually, let me use a different tool so it can look smoother. This is my hand and I'm not good at drawing hands, so you're going to have to forgive me here. So that's one finger, two fingers, three fingers, four fingers ... Don't judge the way my hands look. Okay, so this is my hand. And what we end up seeing in those individuals ... And the mechanism of this is not fully understood. It does have to do with the fact that we have less oxygen, but what we end up seeing is what's called clubbing of the fingers. So you can see these fingers are getting significantly thicker. You see that especially towards the ends of the fingers. And that is called clubbing. So with Eisenmenger syndrome, we have decrease in oxygen levels because of the fact that we have a right to left shunting of blood so that de-oxygenated blood is going throughout the body. That is resulting in decreased function. It's also resulting in cyanosis, polycythemia, and clubbing of the fingers.