Blood Flow Through the Heart: The Complete Pathway (NCLEX®)

When you get those tricky cardiac questions on your nursing exams and the NCLEX, you're going to need to know how the blood flows through the heart, or you could get those questions wrong. So we're going to make sure you understand it all today. Let's dive in. So the heart is divided up into 4 main chambers. You've got the right atrium, the right ventricle, the left atrium, and the left ventricle. Now, don't worry, I've got a bunch of memory tricks throughout this video to help make this all click for you. That's what we do around here. The right side of the heart pumps blood to the lungs, and the left side of the heart pumps blood to the rest of the body. So you can think right for respiratory, R and R, and left for literally all the other things, all the other places in the body. So that's how I like to remember which side of the heart pumps where. So think right for respiratory, and left for literally all the other things. All the other things. all the other parts of the body. And when you think of the heart chambers, you have the 2 atria up on the top, then you have the 2 ventricles on the bottom. Think A comes before V, so the atria are on top of those ventricles. Now, this is usually the part where students get majorly tripped up, so let's just make it easy for you, okay? We've also got a few valves here that are super important to know about for your exams, but they're really easy to get confused on. So we've got the tricuspid valve, the pulmonic valve, the bicuspid, or mitral valve, and the aortic valve. Now, the 2 valves that students get confused with the most are the tricuspid valve and the bicuspid valve, which is also called the mitral valve. So I have a few memory tricks to help you out with this and help make it click. So the tricuspid valve is on the right side of the heart, so think that you always try to do the right The tricuspid valve is on the right side of the heart, so you try to do right. And then the tricuspid valve comes before the bicuspid valve. So for this one, you can either think try before you buy, or you ride a tricycle before you ride a bicycle. Tricycle before bicycle. So the tricuspid valve comes before the bicuspid valve. Now the next one is super important to know, and it's this: Arteries carry blood away from the heart, and veins carry blood to the heart. Okay, now this is really important for you to know for your exams. The blood flow loses pressure as it moves through the body. The further it gets away from the heart, then the less pressure it has, so the veins have valves that keep the blood flowing back to the heart. So in order to remember all of this, I like to think that arteries go away, and veins have valves. Okay? Arteries move blood away from the heart, and the veins have the valves to keep blood moving back to the heart. So arteries, away, and veins, valves. Now, I want you to keep this one in mind, because in just a minute, I'm going to show you one super important thing that you've got to know about these arteries and veins, as we walk through how the blood moves through the heart and through the body. Now, I know this can be pretty tricky as we follow the pathway of blood flow through the heart. And critically thinking in nursing school can be very, very difficult, so I actually made a free critical thinking cheat sheet for you to help you really understand how concepts connect together, and how the patho leads to the signs and symptoms, and the interventions, and the assessments that you will do as a nurse. So comment the word think down below, and I'll send you over my free critical thinking cheat sheet to help you out with that as you study. Alrighty, so let's draw this out, we'll make it totally click for you. We'll start in the right atrium, Where the blood just came in from the rest of the body, and it has given away all of its oxygen. This is now what we call deoxygenated blood. So it doesn't have any oxygen in it. Now, this deoxygenated blood flows from the body via the inferior and superior vena cava, and from the coronary veins through the coronary sinus, and it gets dumped into the right atrium. So blood moves from the right atrium, then through the tricuspid valve, and into the right ventricle. Now, here's something I want you to notice about that right ventricle, okay? And it's that the wall of it is a lot thinner than the wall of the left ventricle. There's a really good reason for this. It only has to push blood over to the lungs, so it's a short trip there, and it doesn't need a whole lot of pressure in order to get it there. So the right ventricle does not need to be a bodybuilder, right? It just needs to get the blood right next door, Right to the lungs. Then from the right ventricle, it goes through the pulmonic valve, into the pulmonary arteries— pulmonic, as in pulmonary, right?— and into the lungs. So you can think pulmonary for the lungs. Pulmonic, pulmonary, lungs. Now here's what I was talking about just a minute ago. This is super important for you. Look at what those pulmonary arteries are carrying. It's deoxygenated blood. Blood that doesn't have oxygen in it. Now this is tricky. Because we've always been told that the arteries carry oxygenated blood, and when you see pictures of blood circulation in the body, right, the arteries are tending to be red, right? But remember what we just said: arteries equal away. It's not arteries equal oxygen. That word artery is telling you the direction that the blood is flowing. It is not telling you the color of the blood. Okay, and right here, the blood is leaving the heart to go pick up its oxygen, right? So it, of course, it doesn't have any blood yet. And in an adult, there are only 2 arteries in the whole body that carry deoxygenated blood. All of the others are oxygenated. Okay, so don't get tripped up on this. Okay. Now the lungs then do their job of gas exchange, and they put more oxygen into the blood, making it now oxygenated, and the blood now has oxygen in it. So now it's called oxygenated Blood. Fancy that. Then, from the lungs, the blood moves back into the pulmonary veins, and we know veins go to the heart, right? And then the blood moves into the left atrium, moves through the bicuspid valve, which is AKA the mitral valve, and into the left ventricle of the heart. And there it is again, flipped the other way, right? In the adult, the pulmonary veins are the only veins in the body that carry oxygenated blood. And it's the exact same rule we just talked about. The direction of that blood flow is what matters. So when we call it a vein or artery, it's either going to or away from the heart, it's not the color of it. Now again, this one is really important. The left ventricle has the thickest wall in the heart. And by now, you can probably tell why. It has to push blood all the way up to your brain, and all the way to your fingertips, right? All the way down to your feet and toes. And it has to go against all of that resistance of the whole body. So that's a long trip for all of that blood to take, so it needs a lot more pressure. And this is why the left side of the heart tends to be kind of like a bodybuilder, right? It's the thickest side because that muscle has to be stronger. So then from here in the left ventricle, it moves through the aortic valve and into the aorta, and then out to the rest of the body. Now obviously, you can think aortic Aorta. Super fun. That's an easy one to remember. Now, your nursing school exams aren't going to test you directly on how the blood moves through the heart, right? They're going to test you on how well you can critically think through it all, and understand it, and apply it to a patient scenario question, or to a case study. Those are so common. So you're going to get cardiac questions on Things like heart failure, valve disorders, and vascular disorders. So it's not enough to just understand how the blood moves through the heart, you also have to understand how to apply it and critically think about it. And I have some NCLEX practice questions that we'll go through here to help this all click for you. So let's do it. Now, right up front, there's one rule you have to know: blood backs up behind where the heart Is broken. Okay, if the left side of the heart is broken, if it fails, it backs up into the lungs. If the right side of the heart is broken, if it fails, it backs up blood into the body. So here's your rule: so the right side of the heart pumps blood to the lungs, the respiratory system, right? When it fails, it can't go forward to those lungs, so where's blood gonna back up? It's gonna back up into the body. And remember that that left is for literally all the other places, right? The left side of the heart is pumping blood to all throughout the body, but if it can't, if it can't go forward to the body, where is it going to back up? It's going to back up into the lungs. So honestly, I think this is the biggest part when you're learning anything in nursing school, this is the critical thinking piece, okay? This is so important. As long as you understand the anatomy and physiology, and then the pathophysiology, then you are not just memorizing things in nursing school, but you're actually going to be understanding it, and critically thinking, and reasoning through it all. So let's walk through a couple NCLEX practice questions to test your critical thinking. Number 1: Mrs. Pancake is admitted with left-sided heart failure. Which finding would the nurse expect? Now here are answers that are possible: jugular venous distension, crackles in the lung bases, pitting edema in both ankles, or an enlarged, tender liver. Now let's walk it backwards from the left ventricle, okay? We have the left atrium, We have the pulmonary veins, and then the lungs. So when the left pump of the heart fails, the fluid backs up into the lungs, and you would hear crackles. A, C, and D are in the body, which is what backs up when the right side fails. Blood backs up behind where it's broken. That's our principle. Now here's your second question: Mr. Tater Tot is admitted with right-sided heart failure, so which finding would the nurse expect? Here's our answers: pink frothy sputum, orthopnea, Pitting edema in both ankles. Or crackles in the lung bases. So let's think through this. I know it feels backwards, my friend. The right side pumps forward to the lungs, so when it fails, the fluid does not go to the lungs, it goes behind it, okay, out back to the body. Swollen ankles, bulging neck veins, big belly. So A, B, and D, those are all left side symptoms because the left side backs up to the lungs. But the right side backs up to the body. So actually, one of the biggest disorders that you're going to learn about in nursing school that involves the blood flow through the heart is, of course, heart failure. So this, of course, is why it's so important that you understand pathophysiology and how it works in nursing school. The more you understand the patho behind everything, the more you'll be able to critically think through everything you're learning. So click on this video right here, and I'll walk you through exactly how to study pathophysiology physiology in nursing school, so everything clicks. And be sure to comment the word think down below, and I'll send you my free critical thinking cheat sheet. And as always, my friend, go become the nurse that God created only you to be. And I'll see you over there in that next video. Bye!