Hypertension is high blood pressure determined by three factors: stroke volume (blood pumped per beat), peripheral vascular resistance (vessel size), and heart rate. Narrower vessels and faster heartbeats both raise pressure. Blood pressure thresholds have recently changed, so verify your nursing program's standards.
In this video, we are going to dive into hypertension pathophysiology. But before we get started, don't forget to download the Med Surg checklist that I have for you that walks you through, step by step, how to study med Surg in nursing school. That link is down below for you to download it. And while you're at it, make sure that you hit that subscribe button and click that little bell icon to get notified when we post a new video here on the Nursing School show. Now let's talk about the pathophysiology of hypertension. Alrighty. So hypertension just means high blood pressure and blood pressure means exactly what it says it does. It's the pressure of blood in the blood vessels. And there are two numbers that you need to look at, the systolic blood pressure and the diastolic blood pressure. I know these numbers can be a bit confusing at first, so let's break it all down. Now, the systolic blood pressure is that top number. And this one indicates the pressure of blood in the blood vessels when the heart actually contracts. So each time your heart beats, it's contracting and pushing blood to the lungs into the body. So the systolic blood pressure is the measurement of the amount of pressure the blood is exerting on those blood vessels during the heart contraction. Now, on the flip side, diastolic blood pressure is the bottom number, and that is the pressure the blood puts on the vessels when the heart is actually relaxed and in between contractions. So when the heart is at and relaxed, how much pressure is the blood putting on the blood vessels? And that is the diastolic blood pressure number. So I'm not going to dive into the blood pressure number criteria here, give you actual numbers. They have actually changed recently. So you'll want to check with your nursing school and your clinical facility to see exactly what numbers they use to define high blood pressure. I don't want to steer you the wrong way if the numbers that I use might be different from the ones your school uses, so definitely check with them. So that systolic blood pressure number is the top number, and we would expect that to be greater than the diastolic number or the bottom number, because that systolic number indicates the amount of pressure the blood is putting on the blood vessels during the heart contraction when the heart is actually pumping. Right. Whereas that diastolic blood pressure number indicates the pressure in between heart contractions when the heart is more relaxed. So that higher number should greater because there is a higher pressure. Does that make Sense. Okie dokie. So let's really get down into the pathophysiology here because we know that blood pressure is the pressure the blood exerts on the vessels. Blood pressure changes when the pressure changes. And some things that can impact the pressure are the amount of blood that the left ventricle pumps out. This is called the stroke volume, the size of the blood vessels, which changes the peripheral vascular resistance and the heart rate. So any changes to these three things can cause changes in the blood pressure. So let's talk about each one of these three things a little bit more. So in the case of stroke volume, this means that the amount of blood that the left ventricle pumps out to the body. So if stroke volume increases, meaning the amount of blood the heart is actually pumping out increases, what's going to happen to the blood pressure? It's going to go up. Right, because that amount of blood increased. Now let's put a visual to this. Now I like to think of blood pressure as a hose. If you turn on the hose just slightly, it just kind of trickles out a little bit, right? This represents a low stroke volume because there's less water coming out. Now, if you try to have a water fight with just a small trickle of water, it's not super effective because there's just not enough pressure. You can't spray someone enough with just a little trickle of water. So if the stroke volume is lower, we would expect that blood pressure to be lower. Now on the other hand, if you crank that water hose way up, it spews out everywhere and there's a ton of pressure, right? You've changed the volume or the amount of water coming out. So with a higher stroke volume, we would expect a higher blood pressure. If you've had a water fight before and this example is making sense to you, write love in the comments below. I want to hear from you, make sure that all this is making sense. Now let's talk about the size of the blood vessels. Now, the size of the blood vessels impact something called peripheral vascular resistance. So when you hear the phrase peripheral vascular resistance, all I want you to think about is how much is the heart going to need to work to push that blood out. That's all. So back to our hose example. If the water hose itself is smaller or more narrow, what will happen to the pressure it will increase? Right? I know you've had a water fight at some point in your life. So what do you do if the water hose can't quite reach the person you're trying to Spray, you put your thumb on it, right? And that makes it spray farther because that pressure is greater. So when you make the hole in the hose smaller, you increase the resistance and that increased the pressure. The heart is the exact same way. If the blood vessels are more narrow, there is more peripheral vascular resistance and the blood pressure will be greater. It'll go up. Now, on the flip side, if the blood vessels are dilated or larger, there is less peripheral vascular resistance and therefore the blood pressure will be lower. And finally, heart rate is the last factor here. The faster the heart pumps, the greater the stroke volume and therefore the greater the blood pressure and the slower the heart pumps, the stroke volume will be less and less and therefore the blood pressure will decrease. Now, to remember this, I just like to think about that water hose having three water spigots all going to one hose. So just imagine that you've got three water faucets or water spigots and they all lead to the same place. So the more faucets you have, the greater the pressure. The less faucets you have, the lower the pressure. Right now, heart rate is the same way. The faster the heart beats, the greater the pressure. The slower the heart beats, the lower the pressure. Now, I hope all that makes sense. Now, if this is all clicking for you, write love in the comments below and let me know. And that is the pathophysiology of hypertension, friend. Now, if you want to go even further with this and dive into the physiological processes that actually balance blood pressure out, things like the RA pathway, baroreceptors, fluid changes, then you'll definitely want to join the Nursing SOP membership community where I'll walk you through all those processes more in depth and how they relate to blood pressure. So if you need to know how the kidneys and baroreceptors impact fluid volume and blood pressure, you will definitely want to jump into the Nursing SOS membership community. And don't forget to download that free med search study checklist that I've got for you. That link is down below. And as always, thank you so much for watching, friend. Now go become the nurse that God created only you to be. And I will catch you next time on the Nursing School show. Take care of.
