Renin-Angiotensin-Aldosterone System

welcome to this video on the renin-angiotensin aldosterone system the key idea from this video is that the Rena and angiotensin aldosterone system raises blood pressure if there's one thing that you take away from this video that should be a take away idea okay so all of this starts with the kidney when it is able to recognize low blood pressure so the kidneys can see that are able to sense low blood pressure and I'm going to use BP or low blood volume I'll write that out all the way and they sense it with specialized cells near their CAG lemare Euler capillary beds call called the juxtaglomerular apparatus so this is sensed by the juxta glomerular oops i'm in or not remember this is all one word but juxtaglomerular apparatus and you can just call that the JGA so when the JGA senses low blood volume or low blood pressure then the kidney will release an enzyme called renin i'm going to use a green highlighter for this arrow let's write lean in with the green pen it's called reading because the word reading literally means kidney okay so meanwhile your lovely liver that's always working hard for you has been making all the plasma proteins that you need and one of these plasma proteins is called angiotensinogen so let's put over here that the liver juices plasma proteins you might remember that the most common one it makes is albumin but the one that we care about in this video is called angiotensinogen you can learn a little bit about what it's going to do just by the makeup of the word angio means vessel and then you can see the tensing so that's gonna why it's going to raise blood pressure but the Oh Jen tells you that it's currently inactive it's going to be the generator of something that will raise blood pressure but it's not yet currently active so let's use the green to show this arrow that the liver is producing angiotensinogen and then angiotensin is 10 cinnamon is converted by this enzyme renin into angiotensin one i'm going to use another blue pen and angiotensin one is not very active it really needs a little bit more adjustment by yet another enzyme so we're gonna move down a little bit and this next enzyme is going to convert angiotensinogen or sorry angiotensin one into angiotensin 2 sometimes this is just cold a two so put a blue arrow right here so this is gonna get converted into its potent hormone and it is converted by an enzyme and we'll put the enzyme in green and try to fit all this in this bubble it's a big named angiotensin converting enzyme but we just call it by the acronym ace now this is made in a few places in the body but on this paper we're just drawing the lungs because that's where most of the ace in our body comes from you can highlight the lungs in yellow so okay so you're ready for what it does remember it's going to raise blood pressure right so it's going to do it in three ways let's go like this and we'll look at these three ways so the first is it's going to constrict blood vessels the second is that it's going to make a hormone called aldosterone come out of the adrenal cortex and the third is that it's going to make a hormone called antidiuretic hormone come out of the pituitary gland so you can go ahead and color this blood vessel pink and specifically I'm really thinking about arterioles here because they're the ones that have the biggest impact on raising peripheral resistance to increase blood pressure then the adrenal gland I'll put that in purple and the pituitary gland will okay so now get a purple pen and the first thing I want you to write over here is constricts blood vessels and the way to make the biggest impact on blood pressure in the body is to constrict arterioles because these really regulate blood flow and keep the blood in the main arteries if they are constricted and then that is going to raise blood pressure then the second thing it's going to do is stimulate so at angiotensin ii is going to stimulate the adrenal cortex of the so this whole thing is the adrenal gland and the outside is the cortex to release another hormone called aldosterone and that's going to make the kidneys reabsorb more salt and that is going to raise blood pressure and then the third thing it's going to do is stimulate the posterior pituitary gland up in the brain to release a hormone called antidiuretic hormone so this is anti diuretic meaning it's going to make you pee less that's how it got named it's not instead of being a diuretic it's an antidiuretic and we call this a th but you should also know that clinically I usually see this called vasopressin okay so let's go ahead and put these purple in purple boxes so those are the three effects of angiotensin 2 and they all are going to raise blood pressure so what happens is that first of all when you constrict arterioles and we'll put this we'll keep this in purple and go down just a little bit when you constrict arterioles you will increase peripheral resistance and that raises broad blood pressure because the blood has more resistance to flow so let's put that in big block letters raises blood pressure okay now what about at the kidney well not surprisingly it's going to have a similar end result of raising blood pressure and what happens here is that aldosterone causes the kidney to reabsorb more salt so I'm just going to use an upward here increases sodium reabsorption in the kidney and what that does is increase blood volume so we'll use another upward arrow this increases blood volume and that increases peripheral resistance too so this raises blood pressure you think you're gonna remember that the everything we're doing here raises blood pressure so angiotensin angiotensin 2 is one of the most powerful hormones to raise blood pressure for these reasons okay then here we go again use your pink highlighter here for the kidney I guess I'm using purple for these arrows right here and continuing with my purple pen so vasopressin or antidiuretic hormone let's write them both so that you start to understand that they are the same hormone with two different names so this will increase water reabsorption at the kidney so instead of retaining more salt and then water follows salt that's how the aldosterone does it's sort of an indirect or indirect way of raising blood volume this is a direct way to raise blood volume because you're increasing water reabsorption so same idea though this increases blood volume and raises blood pressure so when I told you that the Rena and aldosterone arena and angiotensin aldosterone system raises blood pressure it ultimately does it in three ways one by constricting arterioles to raise blood pressure a second way by causing the kidneys to reabsorb more salt water follow salt blood volume goes up blood pressure goes up and by increasing the release of ADH which increases water reabsorption in the kidney to increase blood volume and then raise blood pressure so that's really the gist of it and then the last part of this video is if you're interested in knowing how a lot of medications act on the system in order to lower blood pressure so let's go all the way back up to the top of the page and we'll start at the kidney you can use an orange pen for this so we're gonna have some different inhibitors and each one will do an orange so the first inhibitor would be to inhibit the release of reading so when I do inhibition I like to do a block symbol like that so instead of an arrow we make a flatline and say okay that got inhibited so renal inhibitors so these are pharmaceutical drugs that can inhibit the release of renin from the kidney and a famous one beta blockers which most people know works on the heart to lower blood pressure that way also actually works on the kidney to release or to inhibit rina so this is going to decrease blood pressure so when the down arrow means it's decreasing BP is blood pressure so that's one way we could put an orange box around this inhibitory process okay so then the second really popular drug are ACE inhibitors so again use your orange pen and here we want to have an arrow inhibiting the release of ACE just do this right here so here's your line and then the blocking so ACE inhibitors will really inhibit the this enzyme so it can't convert angiotensin one into angiotensin 2 and in that way it's going to lower blood blood pressure so they block this enzyme and they decrease blood pressure we can use our orange highlighter to put a box around the second inhibitory strategy okay then the third medication is when they try to just block the effects directly of angiotensin 2 and that would be with C they block the receptors on all of these organs they block the receptors for angiotensin 2 so I think the easiest way to do this will just put a line here like that and these drugs are called angiotensin receptor blockers and we just abbreviate these as ARBs ARB these will inhibit the activity of a2 because it can't bind to its targets and in so doing it will decrease blood pressure so that's a third drug target the common way that drugs work by inhibiting a receptor that the hormone binds to and then we're not done yet we have two more ways so you can also take medications that directly inhibit the attachment or sorry the active yeah The Binding of aldosterone to its receptors in the kidney so in this one we could put just a line like this a little one and I'm gonna call it aldo for short so aldo antagonists these would be drugs that antagonize the binding of aldo to the kidney meaning they're gonna block it and these will lower blood pressure you're wondering why they have to try so many approaches I'll also tell you that a lot of times the body finds a way around this so if you try to block something it just crank something else up and then the person still has high blood pressure so to be perfectly honest I'm not a huge fan of a lot of these if you can avoid treatment with the drugs but I know a lot of students need to learn them so we are putting them on here okay then this one has the funniest name vApp Tain's these are inhibitors of vasopressin and so these inhibit the action and binding of ADH or vasopressin I'll just put a ths if it's easier here and that will decrease blood pressure so angiotensin 2 ultimately increases blood pressure and so all the drugs are then that are trying to work against this Reena angiotensin aldosterone system try to work by inhibiting that this process at one or more points along the way all right I will see you in the next video

Channel: susannaheinze

Views: 33,230

Rating: 4.9227271 out of 5

Keywords: RAAS, renin, angiotensin, aldosterone, blood pressure, antidiuretic hormone, ADH, vasopressin, ACE inhibitors

Id: qTPqjDD0vhY

Length: 16min 27sec (987 seconds)

Published: Sat Apr 27 2019