Understanding the Renin-Angiotensin-Aldosterone System

Hey everyone, it's here with registerednurse, Ariane.com, and today we're going to talk about the Renin-Angiotensin-Aldosterone system, also called the RAS system. And as always, after you get done watching this YouTube video, you can access a free quiz that will test you on this system. So let's get started. What does this system do and what is its whole goal? Well, the RAS system, what it does is it manages our blood pressure, specifically when that blood pressure drops. So what it's going to do is it's going to kick into gear and it's going to increase the blood pressure by getting a naturally occurring substance on board in the body called angiotensin 2. So that is the whole goal of this system is to get angiotensin 2 activated and functioning to help cause major vasoconstriction in the body because when we constrict vessels we increase blood pressure. Plus, angiotensin 2 will help increase our blood volume as well, which will also increase our pressure. So, let's go through this system step by step until we get to the end result, angiotensin 2. Now, as we study this, really let the names of these substances help you out because it's called the renin-angiotensin-aldosterone system. And this is really the sequence of how these substances are released. So very first thing happens, our blood pressure drops. The body senses this and says, oh no, we've got to deal with this. So the sympathetic nervous system is stimulated. And remember, this is our fight or flight system that helps save our life. So these nerves stimulate the kidneys, specifically these cells called juxtaglomerular cells, also called JG cells. And these cells are stimulated and they will release a substance called renin, which is the first part of our system. So renin enters into circulation. Now, as it's floating through circulation, it's going to do something. It's going to activate a substance in the liver called angiotensinogen. And once this substance is activated because of this renin, it is going to turn into angiotensin 1. Now remember we need to get to angiotensin 2. So we have angiotensin so we're in the second part of our whole system name and since this angiotensin is in the system in the vessels it is going to really get this ACE involved because we need ACE. ACE is going to help us convert angiotensin 1 into angiotensin 2. ACE stands for angiotensin converting enzyme. So it's going to convert it for us. This ACE is found on the surface of the lung and kidneys in the endothelium. It's going to convert our angiotensin 1 to angiotensin 2. Now we're here. We have this awesome active vasoconstrictor agent in our body that's going to help us increase our blood pressure. But how does it do that? We need to talk about... aldosterone, right? Okay, so angiotensin 2, it's going to act on our smooth muscle vessels. It's going to constrict our vessels. When we constrict vessels, that's going to increase systemic vascular resistance and increase our blood pressure. To help you visualize it or understand it, think about a water hose. When we take that water hose and we narrow it, what happens to the pressure of the water coming out? It's really going to increase. Now, another way we can increase the the water, the pressure coming out of that water hose is if we increase the volume of the amount of water coming out of that hose. So we go to that faucet, turn it up, that's going to increase the pressure even more. So that's what this angiotensin II is also going to do. So it's not only going to constrict our vessels, but it's going to help increase blood volume. Now, how does it do this? Well, it stimulates some other things. Number one, our kidneys are going to be stimulated. Kidneys are going to start conserving sodium and water at those tubular sites within the the nephron. It's influenced by another substance which is produced by the adrenal cortex called aldosterone which is the last part of the name of our system. Aldosterone is going to also cause the kidneys to keep sodium in water and it can also lower our potassium level because the kidneys will start to excrete it. Another gland that's going to be stimulated because of this angiotensin. in two is the pituitary gland and it's going to release a substance called adh anti-diuretic hormone also called vasopressin and what this substance does is it causes This is our kidneys to keep water. So we're keeping water, even more water. We're gonna keep more water and sodium over here and the kidneys are gonna do that. So what it's gonna do is it's going to increase the volume of blood which is going to increase our blood pressure even more. So the end result of this RAS system, whenever it is working correctly, is we are going to increase our blood pressure. Now, in the previous lecture, we talked about ACE inhibitors. And these medications, what do they do? they help lower the blood pressure and right here what ACE inhibitors do they prevent this ACE the angiotensin converting enzyme from working and so you don't get the conversion of angiotensin 1 to angiotensin 2 so we have lower blood pressure now let's illustrate this and do a quick recap of this RAS system so it will stick in your mind so we have that drop in blood pressure sympathetic nervous system is stimulated which will send nerve impulses to those JG cells in the kidneys, which will cause them to release renin into the circulation. When renin is present in the circulation, it's going to activate a substance in the liver called angiotensinogen. And this will turn into angiotensin 1. Now we want angiotensin 1 to turn into that active vasoconstrictor. So to do that, you have to have ACE, which is angiotensin converting enzyme. And remember, this was found on the end. endothelium in the lung and the kidneys. So ACE will turn angiotensin 1 into angiotensin 2. And angiotensin 2, it's going to have some effects on the body. One thing it's going to do is it's going to cause vasoconstriction. So constrict those vessels. It's going to cause the kidneys to keep sodium and water, which is going to help increase blood volume. Also, you're going to have aldosterone being produced by the adrenal cortex, and that's found on top of the kidneys. And is going to help the kidneys also keep sodium and water. But remember, potassium will be excreted. And then we also have the pituitary gland who is going to produce antidiuretic hormone, ADH, and that's going to cause the body to keep water. Altogether, they want to increase blood volume. We're constricting vessels and this angiotensin 2 is going to help us increase blood pressure. Okay, so that wraps up this review over the Rannan. angiotensin aldosterone system. Thank you so much for watching. Don't forget to take the free quiz and to subscribe to our channel for more videos.

So what it's going to do is it's going to kick into gear and it's going to increase the blood pressure by getting a naturally occurring substance on board in the body called angiotensin 2. So that is the whole goal of this system is to get angiotensin 2 activated and functioning to help cause major vasoconstriction in the body because when we constrict vessels we increase blood pressure. Plus, angiotensin 2 will help increase our blood volume as well, which will also increase our pressure. So, let's go through this system step by step until we get to the end result, angiotensin 2. Now, as we study this, really let the names of these substances help you out because it's called the renin-angiotensin-aldosterone system. And this is really the sequence of how these substances are released.

So very first thing happens, our blood pressure drops. The body senses this and says, oh no, we've got to deal with this. So the sympathetic nervous system is stimulated.

And remember, this is our fight or flight system that helps save our life. So these nerves stimulate the kidneys, specifically these cells called juxtaglomerular cells, also called JG cells. And these cells are stimulated and they will release a substance called renin, which is the first part of our system. So renin enters into circulation.

Now, as it's floating through circulation, it's going to do something. It's going to activate a substance in the liver called angiotensinogen. And once this substance is activated because of this renin, it is going to turn into angiotensin 1. Now remember we need to get to angiotensin 2. So we have angiotensin so we're in the second part of our whole system name and since this angiotensin is in the system in the vessels it is going to really get this ACE involved because we need ACE. ACE is going to help us convert angiotensin 1 into angiotensin 2. ACE stands for angiotensin converting enzyme.

So it's going to convert it for us. This ACE is found on the surface of the lung and kidneys in the endothelium. It's going to convert our angiotensin 1 to angiotensin 2. Now we're here.

We have this awesome active vasoconstrictor agent in our body that's going to help us increase our blood pressure. But how does it do that? We need to talk about...

aldosterone, right? Okay, so angiotensin 2, it's going to act on our smooth muscle vessels. It's going to constrict our vessels.

When we constrict vessels, that's going to increase systemic vascular resistance and increase our blood pressure. To help you visualize it or understand it, think about a water hose. When we take that water hose and we narrow it, what happens to the pressure of the water coming out? It's really going to increase. Now, another way we can increase the the water, the pressure coming out of that water hose is if we increase the volume of the amount of water coming out of that hose.

So we go to that faucet, turn it up, that's going to increase the pressure even more. So that's what this angiotensin II is also going to do. So it's not only going to constrict our vessels, but it's going to help increase blood volume. Now, how does it do this?

Well, it stimulates some other things. Number one, our kidneys are going to be stimulated. Kidneys are going to start conserving sodium and water at those tubular sites within the the nephron. It's influenced by another substance which is produced by the adrenal cortex called aldosterone which is the last part of the name of our system. Aldosterone is going to also cause the kidneys to keep sodium in water and it can also lower our potassium level because the kidneys will start to excrete it.

Another gland that's going to be stimulated because of this angiotensin. in two is the pituitary gland and it's going to release a substance called adh anti-diuretic hormone also called vasopressin and what this substance does is it causes This is our kidneys to keep water. So we're keeping water, even more water. We're gonna keep more water and sodium over here and the kidneys are gonna do that. So what it's gonna do is it's going to increase the volume of blood which is going to increase our blood pressure even more.

So the end result of this RAS system, whenever it is working correctly, is we are going to increase our blood pressure. Now, in the previous lecture, we talked about ACE inhibitors. And these medications, what do they do? they help lower the blood pressure and right here what ACE inhibitors do they prevent this ACE the angiotensin converting enzyme from working and so you don't get the conversion of angiotensin 1 to angiotensin 2 so we have lower blood pressure now let's illustrate this and do a quick recap of this RAS system so it will stick in your mind so we have that drop in blood pressure sympathetic nervous system is stimulated which will send nerve impulses to those JG cells in the kidneys, which will cause them to release renin into the circulation.

When renin is present in the circulation, it's going to activate a substance in the liver called angiotensinogen. And this will turn into angiotensin 1. Now we want angiotensin 1 to turn into that active vasoconstrictor. So to do that, you have to have ACE, which is angiotensin converting enzyme. And remember, this was found on the end. endothelium in the lung and the kidneys.

So ACE will turn angiotensin 1 into angiotensin 2. And angiotensin 2, it's going to have some effects on the body. One thing it's going to do is it's going to cause vasoconstriction. So constrict those vessels.

It's going to cause the kidneys to keep sodium and water, which is going to help increase blood volume. Also, you're going to have aldosterone being produced by the adrenal cortex, and that's found on top of the kidneys. And is going to help the kidneys also keep sodium and water.

But remember, potassium will be excreted. And then we also have the pituitary gland who is going to produce antidiuretic hormone, ADH, and that's going to cause the body to keep water. Altogether, they want to increase blood volume.

We're constricting vessels and this angiotensin 2 is going to help us increase blood pressure. Okay, so that wraps up this review over the Rannan. angiotensin aldosterone system. Thank you so much for watching. Don't forget to take the free quiz and to subscribe to our channel for more videos.

Transcript for:Understanding the Renin-Angiotensin-Aldosterone System

Transcript for:
Understanding the Renin-Angiotensin-Aldosterone System