ah did I just raise your blood pressure well that's what's going to happen the rest of this video because we're talking about the RAS the renan Angiotensin aldosterone system the whole goal of this process being to raise blood pressure and it all starts with the kidneys you see the kidneys receive a lot of blood about 20% of your cardiac output and when they receive that blood they going to have to filter it out at a certain rate and that rate is around 100 to 120 milliliters every minute this is called the filtration rate and if that filtration rate drops to say 80 m a minute that means that we have a decrease of blood volume similar to if you're using a water filter where you're pouring water on top and it's filtering down if there's less water less pressure on the filter itself it's not going to filter as much and that could cause for the kidneys a toxic accumulation of substances in the blood and we don't like that so the kidneys in response to that low filtration pressure will release an enzyme called renin and this enzyme will hop into the bloodstream and enzymes have to act on a specific substrate some sort of thing that you can see in my short right here but the question question is what are we going to act on here well we're going to act on a specific sub we're going to act on a oh my gosh we are going to act on a specific substance from the liver and this substance is going to be called angiotensinogen now break down this word with me because words matter oen usually refers to some sort of inactive form of something and most of these molecules are produced by the liver and go throughout the blood circulation now angio refers to blood vessel and tensin literally sounds like tension or pressure so if you think about it it's an inactive molecule that might deal with some sort of pressure in blood vessels thus blood pressure which makes sense because that's the goal is to raise blood pressure in this process right so angiotensinogen will go throughout circulation and when the kidneys release that renin the renin is going to cleave this angiotensinogen and now we just formed the molecule Angiotensin 1 now here's the thing with Angiotensin 1 just like angiotensinogen it is a lazy piece of crap it really doesn't do a whole lot for your body in fact it has no physiological value so we need to activate it so after renin cleaves the angiotensinogen creates Angiotensin one that molecule will now travel down to the lungs interestingly enough and the lungs will actually have enzymes on the outside of the cells called Ace now you can maybe guess what this means a stands for Angiotensin converting enzyme and with the help of Ace we are actually going to activate this Angiotensin 1 and turn it into Angiotensin 2 now I like to remember that Angiotensin 2 is the dude it is the one that's actually going to do a whole lot of work so it's a good dude the ones who aren't lazy like Angiotensin one he was a lazy dude but he is the dude he's going to do some work so Angiotensin 2 is going to return back to circulation I'm going to act on three different organs now remember the goal is to raise blood pressure so think about how these organs could increase blood pressure we're going to First Act on What's called the adrenal cortex when it gets to the adrenal cortex is going to bind The receptors in the adrenal cortex is actually going to produce a molecule called aldosterone now aldosterone actually travels to the kidneys themselves and tells the kidneys to reabsorb both salt and water so if salt and water actually come into the kidneys themselves when aldosterone is present instead of filtering it out as urine it's actually going to just throw it right back into the bloodstream after filtration now why would that be important well because remember if we're bringing back fluid and salt into the bloodstream blood volume bumps up therefore we will raise blood pressure wonderful so that's one way now Angiotensin 2 also comes and talks to muscular arteries and they will also have Angiotensin 2 receptors and when Angiotensin binds to those endothelial receptors the blood vessel itself will actually constrict Vaso constriction now if we Vaso constrict the vessels all the fluid the blood inside the vessel is now compressed and that means that there will be a greater force being exerted on the walls of the arteries thus obviously increasing blood pressure now last but not least the Angiotensin 2 can also go and travel to the posterior pituitary gland and the neurons that are reaching down into the posterior pituitary gland from the hypothalamus you can learn more about that there in my endocrine video will release a hormone into the bloodstream called ADH this stands for anti-diuretic hormone now antidiuretic hormone will travel Upstream to the kidneys and begin accumulating in the kidneys and it will tell the kidneys to reabsorb more water back into the bloodstream so if more water is brought back into the bloodstream once again increasing blood volume and blood pressure so that is the widespread effect of angiotensin 2 now if you're going to be a nurse or an aspiring Healthcare professional I recommend you watch this video next because it's going to talk about certain blood pressure medications can actually inhibit this process to lower blood pressure so I'll see you over there in the next video