alright alright alright alright it's time for us to talk about okay this is going to be the functional unit you know kidney that is going to produce the urine okay and as far as the structure stove we looked at this in lab we know that the renal corpuscle here is composed of the red which is the glomerulus and in Bowman's capsule or the renal capsule is that simple squamous epithelium wrapper around it there is a space between the glomerulus and Bowman's capsule okay it's called the capsular space and that's where we are going to get the filtrate from the glomerulus okay we have an afferent arteriole bringing the blood into this capillary bed and we have an efferent arteriole with a bud leaves from a fair arterioles larger than the efferent arteriole because we're lose some lose some stuff and that stuff that was being lost is identified by this green arrow here our key that's the filtrate and that is like the term filtrate here because it's everything it's the good stuff it's the bad stuff it's water that's what we got to deal with okay it's what was in the blood that's able to pass through the capillary and this is a fenestrated capillary in the glomerulus so it has a specific size hole that is going to allow anything smaller than that to fit through the hole and become filtrate okay now there's everything filter across no we still have plenty of water and stuff like that in it but we are going to get considerable quantities of stuff that makes their way into this capsular space okay from there once we have so once we have created this filtrate the next location is in this portion here and this portion here is proximal convoluted tubule and it's big function right here reabsorb water ions and all organic nutrients and by we're getting nutrients we're talking about the things that we can make ATP with and the things that we can build stuff in ourselves with so it's time to take the good stuff back we're gonna take water remember we've got micro villi here in our proximal convoluted tubule to increase the reabsorption now we've already absorbed this stuff once and we did that when we did the small intestine and we got all these organic molecules into the bloodstream and that kind of stuff so we're gonna use the term reabsorption because we've already done it once we're gonna reabsorb it it's on its way out of the body if it stays inside this tube so we want to get it back okay and we want to get back these solids that's all happy to be then okay as radians now okay and this loop of Henle has a portion that is descending it goes down that's where I'm at right now then we actually make the turn the hairpin turn they call it and then we're on the ascending limb but all of this up to this point right here we call the loop of Henle okay so it is a really big tall you okay and it's there's different functions on our loop of Henle okay whenever you see the thin filament the thin tube you'll portion okay that portion is responsible for water okay water is able to go across it in the thick portion we're able to actively move solids out of the tube okay so both sides have a thin and a thick segments to them but they're doing two completely different things okay if it's the thin segment it's all about water and we got those on both sides if it's the thick segment it's all about pumping solids across and I'll be more specific about those solids here coming up okay all right once we've cleared the loop of Henle our next portion is the distal convoluted tubule this is the distal convoluted tubules all up in here and notice we've got these coming out meaning we're going to actively transport things across in the form of solids will takes water out of this and look at this error this error is going in okay this arrows going in which means we're able to put things into the tube that we want to get rid of okay we call this secretion it's a very important part of this some things that are too large to make their way across when it goes through the filtration here we're able to stick in way over here okay so as things entering into the tube you'll now that it's inside the tube you'll okay and we've reabsorbed all the good stuff that we want okay and notice that it says is under hormone control okay so we'll talk about these hormones that are gonna affect our ability to reabsorb things okay then we hit the collecting duct collecting duct has multiple nephrons that are joining in okay so it's a big tube and this is the place where we can really make our urine concentrated okay we really make our urine concentrated it says we're gonna reabsorb water that needs to take the water back we can reabsorb some of sodium and potassium and calcium hydrogen ions and that kind of stuff but when it's made its way all the way down and we hit this papillary duct and we make our way into the minor calyx we're done we can't change it at all anymore okay so all of the work that's happening is happening in this structure that we called the nephron okay and it is the functional unit of our kitty somebody that is a kidney specialist that studies the kidney and how its functioning and that kind of stuff specifically they're called a nephrologist okay and they typically are very very intelligent doctors okay so here's our nephron we're gonna walk you through it again consists of the ring will to build that's the stuff to the right of this line all the tubes okay and the renal corpuscle that's our guy over here okay this is where urine production is going to go renal tubular long passageway begins at the corpuscle so again we're right here everything to the rider that's tubular to the left of it is our renal corpuscle okay corpuscle is composed of Bowman's capsule or the renal capsule around the outside here for the nephron capsule and then here is the glomerulus on the inside okay this is our category bed everything to the right of this that is considered the tibial okay glomerulus each one of these little knots of capillaries that you see in red there is about 50 intertwined capillaries and let's come into the efferent arteriole and blood is leaving after being filtered the efferent arteriole okay so filtration that's what's happening up here in this portion here and I like this one because it shows you well it's coming in blood leaving and then this not all of this not in here is the Mary Alice okay and once it leaves there's a nice tap for space as you can see all the way around it for the fluid to make its way into okay it says that this filtrate is a protein free we don't want to find whole proteins in there amino acids are fine but we don't want to lose those big plasma proteins so protein free solution that's very similar similar to our blood plasma okay so blood plasma lots of water lots of nutrients things like that red blood cells not part of the plasma right so it's a fluid portion of this so the big functions in the tube you'll reabsorb the useful nutrients that have entered reabsorb more than 90% of the water we're going to see a lot of water filtered out of this and then number three we're able to secrete that means to put it into the tube waste products that failed to enter through the filtration mechanism at the real corpuscle okay so that's our Biggie's okay when we look at the to bill the segments of the tube you'll okay we've got the proximal convoluted tubules and the distal convoluted tubules to be in the proximal convoluted you'll you got to be in the cortex okay so I'm gonna draw this line here that says okay everything above the line cortex everything below the line medulla okay and then that makes the dark red proximal convoluted tubules that means the peachy colored over here this makes that the distal convoluted tubules you're separated from the proximal and distal by the hairpin loop we called the loop of Henle okay or the nephron loop and again both sides have a thick portion to it and a thin for to it okay so we got different jobs and different functions okay that are gonna happen inside of this now notice while we're here the loop of Henle is what is in the medulla okay the loop of Henle is in the medulla as well as that collecting duct is going to go back through the medulla as we travel along if we cut through new cross sections through the tube which you can see again that in laughs when we're looking at the glomerulus and Bowman's capsule the corpuscles and that kind of stuff we can see a bunch of tubules little cuts through tubes we see different pills in different shapes as we make our way through in lab we see Bowman's capsule on the outside [Music] microscope what's on the inside here that's the glomerulus okay the white part that's the capsular space okay and then once filtration happens notice when we are in the proximal convoluted tubule we've got some different cells and we got micro villi here might reveal I help us to reabsorb things once we get the loop of Henle there's a thin segment a thick segment the thin segment okay it's all about water the thick segment okay it is all about reabsorption of ions and what that's going to do is help us to create a gradient of salt in the medulla salty medulla then the distal convoluted tubules okay little different cells it's all about the reabsorption of sodium and calcium ions and things like this and the ability to put things into the tube via secretion okay and then the collecting duct live larger cells that allow still the ability for us to reabsorb water some sodium things like that okay so the collecting duct that's this pink guy over here here is going to receive fluid from fons we show our scum anything like this here's another net front coming in like this and there would be different ones coming in all over this this okay it starts out in the cortex because that's where your distal convoluted tubule is but that collecting duct descends down into the medulla okay and at the end of the month at the end of the collecting duct there is a little papillary duct that drains into the minor calyx okay it's at that renal papilla a structure short ones they're called cortical nephrons and this line is important right here this is the split between cortex and medulla so cortical nephrons are the short ones okay they're the short ones here and the only thing that sticks into the medulla is just a tiny bit of their loops of him or nephron loop now check out the difference between the juxta which is a much wonder okay a much longer nephron if it reaches way down pretty much throughout the entire medulla region okay now when we look at these there's gonna be a lot more of the cortical nephrons than there are just imaginary nephrons okay they're the workhorses they're doing the Yeomans task of filtration reabsorption things like that and this juxta ventilator nephron it's great because it extends throughout the entire medulla and it's going to allow us to maintain the concentration in the medulla it's gonna help us to pull things out and that's gonna be solved okay now while we've got the picture here look over here on the right hand side and you've got cortical nephrons and you've got a juxta medullary there from a--they at the other side we have a capillary bed it's called peritubular capillaries in the cortical nephrons we call it the phase erecta okay when it's down along the whip of him okay so peritubular capillaries peritubular capillaries peritubular capillaries bays erecta okay and this is where we're gonna see the exchange again because we did filtration up here at the lubricant excuse me at the renal corpuscle okay but notice when it leaves this not after going through a capillary we're saying it's in an efferent arteriole still the artery still on the on the good side okay so we still have oxygen stuff so we're gonna send that down and we're gonna go through this capillary but again and this is where we're going to deliver the oxygen deliver the nutrients pick up the waste and that kind of stuff in both of these so both of these are set up to feed the nephron and then once things are moved out of the tube there's a blood supply in the form of a capillary laying right beside it so if we reabsorb water where does the water go water goes into Buster if we reabsorb sodium porta sodium Gulf goes with Buster calcium goes in blood stream so we're putting it right back as soon as we've absorbed it and that's critical force okay all right as I said cortical nephrons a whole lot more cortical nephrons it's about 85% is that of cortical nephrons that leaves us 15% for the juxta medullary difference says cortical nephrons okay loop of Henle is relatively short the efferent arteriole is going to deliver the blood into this network of peritubular capillaries okay which surround the entire tube you so once we've done filtration here now we have a place to put all of the stuff that we are reabsorbing okay all of that stuff extramedullary nephrons like I said about 15% long loops of Henle that reach way down into the medulla and their capillary bed that is along the side along the outside of the loop of Henle that's called the vase erector okay let's look at this renal corpuscle okay we've got the tube you'll down now let's look at the renal corpuscle they got some good pictures here okay shows you down at the bottom we've got an afferent arteriole bringing and bringing the blood supply in its gonna make its way in and then we've got the Tata Science laying on top of our glomerulus and they're controlling how much filtration they're allowing through these natal BT channels okay now let's take a cut through this right here okay we're gonna cut through this part this part of it so here is our opening and this shows you how big that red blood cell is okay as it's going through the table' remember these about the same diameter blood cell and look at the little holes these are the pores that are going to allow filtration to occur so the stuff that's in here if it's small enough through that hole it'll make its way into this little channel that our hotter side is created and ultimately end up out here in the capsular space okay so that's the way this is going to work here's your bill merula that's this red part here Bowman's capsule that's this outer portion of it simple squamous epithelium around the outside and basically creates containment apparatus as well as a funnel okay it's gonna wall it off but create a place for the filtrate to make its way okay you can see that on our picture out here here's those simple squamous epithelium so filtration this process of filtration is driven by blood pressure it forces water small solutes across the membrane into the capsular space so what pressure is part of this that we are having a control this way and one of the things that we look at is how blood pressure bursting capillary beds so this is one of the things that we have to worry about with individuals with extremely high blood pressure we could see actual blood appear in their urine because they are too high okay larger solids plasma proteins cells platelets things like that these do not make their way through the filtrate okay they stay in the blood stream now the cool thing is this filtration is passive because we're relying on the heart to create the blood pressure blood pressure that's created by the heart in order to pass it all the way around is going to allow for filtration to occur okay so we're gonna push things out okay pressure inside the vessel when we get to the capillary is greater who talked about capillary hydrostatic pressure it's gonna be greater then what's on the outside and that's gonna allow us to move anything small enough out and anything small enough could be vitamins fatty acids amino acids glucose metabolic wastes things like that okay now some of those are good some of those we want to get rid of others we don't okay we just learned in metabolism that how many ATP's can I make from this how many ATP's can I make from this these vitamins are going to be for doing things as we go through don't lose those okay so let's reabsorb so filtration happens in reabsorption happens in the tubules okay greatest amount here in the proximal convoluted tubule it's set up to immediately get those useful materials back okay into the bloodstream okay take it over the tube you'll because if they stay in the tube you'll they're gonna end up in our urine we've gotta get them back so reabsorption occurs in proximal convoluted tubules okay it's that first segment after filtration and the entrance to it is immediately opposite where the blood supply comes in and that creates a pressure gradient from high to low as it goes across and that's gonna force things into from the capsular space into the proximal convoluted tubule from the convoluted tubule rocks McCullar - we enter down into the nephron loop both the loop of Henle it's sometimes called and it is a huge you shaped structure that has both a descending limb and an ascending will okay so the one that's headed down is carrying the filtrate down is the descending limb the one that is headed back up is the ascending limb and each one of these limbs has two parts they have a thick portion and Afghan portion and you can see that on our picture over here again most of the loops of Henle occur down in the medulla okay and that's gonna be important to us so it says the thick descending limb if it's thick okay pumps sodium and chloride now the nice thing is soda is positively charged if we pump sodium since chlorides a negatively charged it wants to go with the positively charged sodium you can't get it too far with that okay the ascending limb okay also to create a high solid concentration in the peritubular fluid this is gonna help us maintain a salty the thin segments think segments are all about sodium and chloride thin segments are about water okay so thick salt thin water okay then we go after we've done that then we're gonna move into the distal convoluted tubule it's the third segment this is where we've done most of the reabsorption already so we don't need my profil out here it's a lot smaller in diameter because we got a lot less stuff we've already reabsorbed a lot of it so the tubular is smaller in diameter it's what's gonna hook a conductor while we're in the distal coma interview we got three functions here the chrétien the number one a lot of students forget about this this is our ability to put big things like drugs toxins acids things like this into the tube you'll even though we weren't able to filter okay second thing reabsorb sodium and calcium okay we've talked about sodium's importance in our muscles in our nervous system so new potassium clumps things like this we've got to maintain the sodium levels in our bodies okay and then the third one it's all about water how much water did you drink if you drank plenty of water we get rid of enough water if you have a drink if you haven't had enough water then can we get rid of more water if we haven't been taking in water so this is where we're doing the selective reabsorption of water depending upon where we're at home aesthetically with the water in our bodies okay then into the collecting system okay that's the clicking ducked meeny miny nephrons are gonna hook into our collecting duct it's gonna make its way back through the medulla give us one this chance to figure out what we want to do concentration wise because we got to go back to the salty medulla okay from the collecting duct into that papillary duct for the papal air duct drain into the calyx so basically we start out doing a bunch of the filtration at proximal convoluted tubule here then the distal convoluted tubules I'm sorry the loop of Henle here back up to the distal convoluted tubule to turtle hooking into a collecting duct it makes its way all the way down and the stuff that is left in our collecting duct ultimately makes its way into the outer connects okay so since transport tubular fluid from the nephron to the renal pelvis that's what we're trying to do as we go through this Bush okay we're headed for this renal pelvis okay as we're heading through here we can do some adjustment here but once we enter into this portion we're done okay we can make some final adjustments in here once you're in the minor calyx and the major calyx and that kind of stuff okay can't really touch concentration wise can't get either good stuff back okay so that's one run through it we're gonna do another run through it okay in the next video so part three is coming up