hey everyone it's nurse Sarah with registered nurse rn.com and in this video I'm going to talk about the hormones and body systems that work to balance the fluid in our body so let's get started the water in our body must be balanced we can't have too much or too little and if we do we start to have major problems so whenever an imbalance starts to occur we have hormones in certain systems in our body that will kick in to hopefully help correct those imbalances so in this lecture we're going to review those hormones and systems so I'm going to be talking about the renin Angiotensin aldosterone system known as Ras I'm also going to be talking about The Thirst mechanism and review those hormones known as antidiuretic hormone which is known as ADH aldosterone and the Nay tree uretic peptide hormones so first let's review the renin Angiotensin aldosterone system also known as Ras okay so let's say you have a patient who has fluid volume deficit so thinking back to our lecture on fluid volume deficit we know that our patient has low fluid in their body and this can cause a low blood pressure and our body doesn't like the low blood pressure so whenever it senses this this rash system is going to kick in and the whole goal of the system is to increase your blood pressure and how it does this is it gets Angiotensin II involved which is a hormone that's also going to stimulate other hormones such as aldosterone and ADH that antidiuretic hormone and those hormones are going to add more water to your blood to help increase blood volume hence increase blood pressure so how this system works is that your blood pressure drops that drop in blood pressure indicates to the body hey we have a loss of fluid so we've got to do something about this and this causes the kidneys to respond specifically the juxta glomerular cells inside that kidney and they are going to release a substance called renin and whenever renin is present in the blood circulation this causes the liver to respond and whenever the liver responds it is going to activate a substance called angiotensinogen and whenever angiotensinogen is there it actually turns into a substance called Angiotensin one so we have Angiotensin one but again the whole goal is to get Angiotensin II involved because that is that big major hormone that's going to actually cause some things to happen so we've got to get there now how do we get there from Angiotensin 1 to Angiotensin II well that is where Ace comes in a stands for Angiotensin converting enzyme and this helps turn Angiotensin 1 into Angiotensin II and now that we have Angiotensin II involved things are going to start getting interesting because now we'll be able to achieve our goal of increasing that blood pressure because Angiotensin II has major effects on the body one thing it does is it cause causes vasoconstriction so we're going to get narrowing of those vessels and when we narrow those vessels it's actually going to constrict the blood flow to the kidneys and limit its ability to excrete water which is what we want because we want that water to stay in the body right now so we can increase our blood volume hence increase our blood pressure in addition Angiotensin II is going to cause our adrenal cortex to release a hormone called aldosterone and aldosterone will cause the kidneys to keep sodium which will also cause us to keep water and again we want to do this because we're trying to increase our blood volume so whenever this happens your patient will have a temporary decrease in their urination which again is what we want and then another thing Angiotensin II does is it causes the posterior pituitary gland to release a hormone called ADH which again is anti-diuretic hormone so how this works is it's going to cause the kidneys to keep water and whenever we keep water we're going to increase blood volume so think of it this way if you're familiar with how diuretics work we get patients diuretics to help them urinate extra fluid out of the body it's used to treat a lot of times fluid volume overload well if we're having a substance in our body called antidiuretic anti-means works against we're working against that concept so let that help you remember what ADH does ADH is going to cause your body to keep water it has an antidiuretic effect and then lastly another thing Angiotensin II does is it stimulates the thirst mechanism so let's review how The Thirst mechanism regulates fluid in our body so when whenever this mechanism is stimulated it's because again of low fluid in the body so whenever you have low fluid in the body think about your blood Plasma's osmolality how's it going to be it's going to be high because you're going to have a low amount of fluid in there but a lot of solutes so whenever we have a high blood plasma osmolality it's going to cause the hypothalamus to respond particularly The osmo receptors inside the hypothalamus and look at that word osmoreceptor we have osmo and we're talking about osmolality so these receptors are very sensitive to how the blood Plasma's osmolality is that's how they respond is based on if it's high so whenever they respond they cause antidiuretic hormone to be released ADH now ADH is also called vasopressin and ADH is actually made in the hypothalamus but it's stored and it's secreted in the posterior your pituitary gland and this is when The Thirst sensation is going to be experienced so the person is going to have this desire to drink fluid so once ADH is secreted it's going to cause the kidneys to respond they sense that ADH hanging out and it's particularly going to cause the nephrons within the kidneys to start doing some things a little bit differently so your nephrons are all those little structures within the kidney that really work to keep the kidney functioning and help create your urine so the ADH is going to act on two particular parts of that nephron it's going to affect the distal convoluted tubule and the collecting duct it's going to cause those structures of the Nephron to actually reabsorb water so instead of taking water and putting it back into that nephron hence into the filtrate so to be urinated out instead it's going to cause your body to reabsorb that water and put it back into the bloodstream which is what we want because we're on a fluid volume deficit and we need water back into the body so water is going to be retained and whenever we retain this water it's going to help our plasma osmolality so instead of being so high and high of solutes we're going to add water back to it help water it down just a little bit and even out the water in the solute concentration so we can normalize the osmolality so we just reviewed hormones and systems in our body that help us correct a fluid imbalance where we don't have enough fluid in the body known as fluid volume deficit it but how do we prevent those systems from doing their job too well where they add way too much fluid into her body and send us into fluid volume overload well we have a group of hormones that help prevent that they really keep those system and hormones in check and they're known as the natureuretic peptide hormones and one of these hormones is known as atrial natriuretic peptide also known as ANP and this hormone is secreted by heart cells when they're a stretching of that atrial wall and remember the Atria are the top chambers of the heart then we also have what's called BNP and you may hear BNP a lot whenever you're taking care of a heart failure patient because these patients are in fluid volume overload and BNP stands for brain natureuretic peptide hormone and this is a hormone that is actually released by The Heart cells whenever there's a lot of ventricle wall stretching so whenever we had the wrasse aldosterone ADH and thirst mechanism doing their thing they were adding water back into our blood system so whenever that water is added back in there it's going to go up and it's got to go into the heart because the heart's job is to pump that extra fluid out throughout the body well when you're adding just too much your heart's going to start to sense that because it just wants to get it at a right point so it doesn't over stretch because it's over stretching those Atrium ventricles because that water that extra water in the blood is going there it's signaling hey we may be going into fluid volume overload so these hormones are secreted by those heart cells that make up the Atria and the ventricles and what these hormones are going to do is they're really cool they actually work against Angiotensin II because Angiotensin II was our big star of the Rye system that's what got aldosterone ADH that thirst mechanism all that involved so it's going to stop the effects of aldosterone ADH in renin so we don't go into a fluid volume overload so it's like a check and balance type hormones that help us manage our fluid okay so that wraps up this video over the hormones and body systems that work to help us balance our fluid in our body if you like to watch more videos in this fluid electrolyte series you can access the link in the YouTube description below