okay so let's go over this Renan to angiotensin - to aldosterone pathway and again remember the granular cells we're going to find those in the juxtaglomerular apparatus near the the afferent arteriole and their jobs are going to release written into the bloodstream so it can convert angiotensinogen into angiotensin one angiotensin one will will circulate to the lungs where there's an enzyme called AC e angiotensin converting enzyme and the angiotensin one will be converted to angiotensin to angiotensin one will be converted to angiotensin 2 in the lungs by the angiotensin converting enzyme now maybe you've heard of ACE inhibitors so that'd be something that would prevent that from happening angiotensin 2 then again you know also causes the efferent arteriole to constrict therefore increasing the glomerular filtration filtration rate okay but what else it does is it goes to the adrenal gland triggering it to actually release aldosterone now aldosterone is ultimately going to help us help us conserve at the water in our urine so it's going to concentrate the urine and not going to let us lose too much water in it it will do that with the help of another hormone called antidiuretic hormone we'll talk about aldosterone actually does it by triggering cells to build setting potassium pumps and in sodium channels and we'll talk about that later but bottom line is aldosterone helps us conserve water instead of losing water so aldosterone is helping us conserve water angiotensin ii has that vasoconstrictor effect and of course ultimately that also helps increase our blood pressure the other thing that will cause aldosterone to be released from the adrenal gland is high concentrations of potassium in our blood so if we have a high concentration of potassium in our blood then it will also when it circulates to the adrenal gland also trigger to release aldosterone which again will help us hold on to more water and not lose as much water in our urine now notice I've got a lot of potassium in the blood here and I've got sodium here in the filtrate which I'm turning into urine okay but since else its potassium helps us increase aldosterone and what aldosterone is going to do is going to go into the cells here in the in the distal convoluted tubules going to cause those cells to build sodium potassium pumps so what it's going to end up doing is pumping the sodium out into the interstitial and the potassium in so it got excess potassium now I have a way to get rid of it okay so again let's look at what's happening aldosterone we needed to help us conserve water what actually does that actually again can be released from the renin aldosterone pathway we talked about more from excess potassium being in our blood so what's the aldosterone is is released it's what it's going to actually activate it's going to act on the cells of the distal convoluted tubules and the collecting duct what it's going to do is going to trigger those cells to build more sodium potassium pumps and what that sodium potassium pumps going to do is going to pump the sodium that was here into the interstitial and then it's going to pump the potassium that was out here in the duct okay now you might say well how does that help with water well any water that's in here once we increase the osmolarity of the interstitial remember water always goes from high water concentration to where there's less water concentration well if I pump a bunch of sodium in here I make it less water concentration therefore water will want to leave and follow it okay now in her picture here I've got set him over here and set him over there and it says drag the sodium in the direction it will move at aldosterone is present well if aldosterone is present it's going to cause the cells in this and the distal convoluted tubules cells in here and the cells in the collecting duct to build sodium potassium pumps what they build sodium potassium pumps they're going to pump sodium into the interstitial so if they're gonna pump sodium in an interstitial then this wouldn't move from the blood to the inter system it would go from here to the interstitial because the aldosterone put the those norway's or those pumps in the cells in the tubules so therefore sodium here would move into the interstitial initially and then eventually back into the blood well again the good thing about that is when I make this interstitial here have a higher osmolarity a higher sodium content water will definitely want to follow that so therefore I'll lose water from the filtrate and it won't continue in the urine so my urine will be more concentrated so if I am dehydrated then I definitely want to pull water out of here in my antidiuretic hormone in my my aldosterone helps me do that okay and again if I've got potassium here and potassium here because I filtered this potassium out but I had excess potassium you know in my in my blood probably due to my diet or some other potential things then aldosterone what does it do again well it helps build sodium potassium pumps we're always pumping more sodium out and potassium back in there's always more soda being pumped out than potassium pumped in but here the question is which way will potassium move well since the aldosterone is is causing these cells in here to build sodium potassium pumps pumping potassium inside therefore the potassium will move from here to here and I will lose more potassium in my urine so if I'm dehydrated I might expect to find a lot of potassium in my urine and here we can see mop testing moved this way now antidiuretic hormone is the other hormone that affects the water and it can work with or without the aldosterone but again what does aldosterone do it triggers the cells in here to build sodium potassium pumps what does antidiuretic hormone do well it's actually released it's actually made in the hypothalamus released to the posterior pituitary then it goes into our bloodstream it's made the hypothalamus because I both Alamos is monitoring our brain for different things and one of the things is monitoring is how hydrated are we do we does our fluid have a high osmolarity meaning we are you know more diluted water so where we don't have as much water are we a little bit more hydrated and have less lower osmolarity so anyway if we have a high osmolarity meaning we're dehydrated the hypothalamus detects that it starts producing antidiuretic hormone actually deposits and releases it from the posterior pituitary now what does antidiuretic hormone do well it also comes to the cells here but it doesn't regulate or have anything to do with the salt or the sodium what it does it actually builds more water channels so if I have more doorways for water to go through it will especially if I increase the osmolarity of the interstitial then the water will definitely want to follow because we know in our toe Nissa t just just you know descriptions that hypertonic solutions draw more water towards them now what I have here are the cells in the lake this will come luteal and the cortical collecting duct okay so that means that here are my two hormones we were just talking about antidiuretic hormone which has to do with water channels and aldosterone that's to do with with our sodium potassium pumps again the aldosterone is actually going to come from the adrenal gland and the info diuretic hormone it's going to come from the pus herb to Terri but it was actually made in the hypothalamus now in this normal luminal cell of course we we've got a sodium channel sodium channel a potassium channel we got a sodium testing pump sodium potassium pump aldosterone however is going to increase the number of pumps there now notice how we have more sodium potassium pumps and we even have more doorways for sodium so what I'm what what we're going to do is we're going to pump all the sodium out of the cell into the interstitial notice how it's darker meaning there's more sodium meaning as a higher osmolarity okay now if I if I build if my hormone tells the cell to build these proteins you guys do you remember transcription and translation and sell signal errs that you know go to the gene that tells me how to build these and and I go through transcription and then we go through translation and actually build it insert it into the cell membrane well now if I'm pumping more sodium out of here then more settings gonna want to run from the higher concentration through the cell where I've pumped it out and eventually be pumped out itself notice that also a potassium well I have my potassium but in this case I'm pumping potassium into the cell so now my potassium is going to go from a high concentration where I pumped it in through the potassium channels into my urine okay now water at this point if I don't have my my antidiuretic hormone water can seep between the cells because again water once again from the high concentration of water to this lower concentration of water and it's a lower concentration of water because I've a higher concentration of other things in other words I've made it a higher concentration of sodium I've increased its osmolarity now notice antidiuretic hormone triggers the cell to build extra water channels so if I increase the osmolarity here and I'm pumping potassium this way sodium this way but always more sodium than potassium I'm increasing the osmolarity and now I put more water channels in here now more water is going to be able to come through this cell and try to equalize this remember it's always trying to reach equilibrium and this whole osmotic gradient of going from high water concentration to where it water is less concentrated until we reach equilibrium is going to hold water out of the filtrate back into the interstitial that fluid that's between the cells of my tubules and the cells of my capillaries so this is called the luminal side because it's next to that filtrate where the lumen is this called the basolateral side because it's next to the interstitial notice again how the out the antidiuretic hormone is not only caused me to build water channels in the loo and the basolateral side but also put them in the luminal side so water easily will come through into the cell and back out of the cell and of course water is running from the high concentration to the lower concentration notice how this is lighter now because the water being removed is is diluting it trying to reach equilibrium with it but ultimately what we're doing is we're pulling water out of the urine so we don't lose too much of it because we shouldn't be releasing these two hormones unless we are dehydrated if we're well hydrated we can afford to lose the water a matter of fact we would want to lose the water okay another important function of the you know these cells these especially cells called intercalated cells is they actually release protons are hydrogen ions into the filtrate because this is another way besides the lung this is the metabolic way that we control our pH so if I'm getting rid of remember are by definition basis receive protons and acids give up protons so if I am balancing that pH level here is where I'm going to give up those protons and not hold onto them to get get rid of protons and put it into my urine so I'm kind of acidifying in a sense my urine so our kidneys are actually getting rid of the waste products from ourselves the nitrogenous wastes that we talked about but they're also balancing my water and ion balance as well as balancing my pH so they do several things along with a secrete the hormone erythropoietin which of course is helping me make my red blood cells so kidneys do several extremely important life giving or life altering the processes that we cannot live without