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Current time:0:00Total duration:7:58

Video transcript

the kidneys are pretty crazy they can hold about 22% of your entire blood supply at any time I've read somewhere that you can have about 1.1 liters per minute of your blood flow through and in a normal person that's got about five liters of blood that means that within five minutes all of your blood will pass through your kidneys that's crazy so I think we should investigate further into how our kidneys work and we'll start in this video with a brief overview before going into the specific parts of what are involved so with these two kidneys right here we're going to take in some blood that'll come in through our renal artery and come out at the end through our ureters right there to produce urine so that's sort of the overview look of what we're going to be doing here and the reason why we do this is because there are cells in our body produce waste products or change up the acidity or the osmolarity of our blood we've heard these terms before and it's very important for us to regulate what is the pH of our blood or how acidic it is or how many osmoles we have or things that dictate where ions or water flows and our kidneys make sure that that's at a set level so going into the details when blood comes into our kidneys they enter through the renal artery so I've got two renal arteries right here one right there one right there and as you can see it's going to go branch off and have a whole bunch of other networks that are going to be disseminated from here and I'll talk a little more about that in a separate video but what happens is that we're going to have filtration of our blood and from that filtrate that comes out we're going to process it and reabsorb some ions and water and as we reabsorb things that are important we're going to collect it into our renal vein so here are two blue renal veins right here for each of our kidneys our renal veins are going to take the returned or reabsorb nutrients back into our blood and send it on its way all right very cool so now we know sort of how the blood enters and leaves now let's talk about the two main functions our kidneys are responsible what are the two main functions that they need to carry out in order for us to filter our blood so the first function you probably guessed is filtration we take our blood and we filter it out so we have all our waste products and some important molecules like ions or amino acids or glucose that end up in a filtrate that then passes through the kidneys so some things in that filtrate we want to get rid of all the waste see stuff that we don't need and so another or the second very important function of our kidneys is collection and between these two jobs the kidney will take our blood and put out some urine now at this point I should also mention that there's a single functional unit and so when we talk about our functions there's a unit that we can talk about the single smallest functional unit of a kidney is called the nephron the nephron and the nephron is responsible for filtration and collection we'll talk about some other structures in a minute that are only responsible for collection but the nephron is charged with filtration and collection so it's got two hats on and the nephron is sort of situated in two parts of the kidney the first part is sort of this outside area right here you can kind of see that it's the shell of the kidney right and as a shell we call it the renal cortex cortex is a term you've probably heard of before right cerebral cortex adrenal cortex cortex just means the shell so that's this light tan part on the outside these darker parts inside right here there's a couple of them that you can see this is sort of in the middle and so we call that the renal medulla the renal medulla and medulla you might have heard of like the adrenal medulla or the medulla oblongata it just means the middle ok the middle so it's inside the cortex so our nephron is situated between the cortex and the medulla it sort of starts up here and squiggles around and then it dips into your medulla and then it jumps back out over here and then it dips in again and so I'll draw that in a Shepard video sort of all the separate parts of the nephron but just understand that it dances between your cortex and your medulla and where it's dancing determines whether it wants to reabsorb important things or allow some stuff to be collected into the urine now for the collection process we have these little tips that are kind of kissing our renal medulla right so these little tips right here that collect the urine in the first place the first point that urine sort of presents itself this is called the renal calyx the renal calyx and if we've got a whole bunch of these we'll call them the renal calyce's the renal calyce's and so that's the first part you're gonna have urine be present there's a whole bunch of these guys that meet together and then you've got this central area right there that central area is called the renal pelvis the renal pelvis and that's just where all your calluses collect together and once you've got urine in your renal pelvis it's gonna go out this tube right here and that's where urine is going to exit our kidneys this tube right there is just called the ureter the ureter and we've got two ureters right here that's going to send urine away from the kidneys and as we'll talk about in a separate video into the bladder and now that we've talked about the ureter this is a pretty good time to mention what these three guys make together whenever you've got an organ like our kidney right here and I'll sort of highlight that that's your kidney and then there are some things that are coming out of your kidney these three guys right there we call the place where we've got tubes or vessels coming out of the hilum the hilum and if we've got more than one of them we can call them the Hilah but we've got a renal artery a renal vein and a ureter coming out of the renal hilum over here all right and so that's the anatomical structure of our kidneys now why don't we take a step back and let me make a philosophical note if I may what's the point of the kidney even doing this why should we even filter and collect urine what's the whole purpose of this altogether well the kidneys are actually a very important or for maintaining something that's called homeostasis and you've probably heard of this term before it's a big buzzword in biology homeostasis just means the way things are the status quo which could mean things like what the pH in your blood is so your kidneys maintain the pH in your blood by regulating the amount of hydrogen ions that are there it could also mean blood pressure because when you have a lot of salt and you've probably heard this from doctors if you have a lot of salt intake you're gonna have high blood pressure so your kidneys make sure you excrete the right amount of sodium and chloride ions to make sure that you don't have high blood pressure but there are other things here that the kidney also maintains homeostasis of and that could be things like osmolarity and of course the main thing that we're going to talk about in an upcoming video is just the excretion of waste products so getting rid of the extra materials that we have and one of the main waste products that the kidney gets rid of is something that's called urea and we'll touch on URI in a little bit but this just goes to show you how important your kidneys really are there's a lot at stake here and so it's very important to have these guys filtering your blood to produce urine to maintain homeostasis
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