this would be Martini chapter 26 this is the kidney or Reno Anatomy as an introduction we'll talk about the fetal development of the kidneys it actually starts three times there's a kidney it's called a prone nephros and it disappears really fast then we have a fetal kidney and then we finally get an adult kidney the term cloa means sewer and that ENT is what your bladder and your in a female vagina and rectum are this starts as a CLA and then it's get subdivided into a bladder and a rectum for males and then bladder vagina and rectum for females and each of those tubes they're attached together so this well they'll discuss again excuse me we get to reproduction the vaginal delivery can really cause problems for the females urethra get stretched all out of shape leads to urinary incontinence the ureteric bud so urer if you look at the word you're and then you're AIC there's an outgrowth of this cloa that is going to form this Bud which will form your urur which are the tubes that connect your kidneys to your bladder when the you follow the urer from the bladder up will expand into What's called the Reno pelvis this is your sink that's leading to your sewer um then the pelvis will Branch into cups kaces cup shaped structures a big one that's major so Big M and um some smaller branches small M minor so if you're into music you know major and minor abbreviations Big M Small M from The KES there actually is a gap but there's a continuation so there's going to be some apotosis happening at the koses that will actually separate the kaces from the collecting ducts the collecting ducts will go up and start branching out to the side to form collecting tubules some people will say [Music] connecting tubal but others will say collecting tobio they're talking about the same thing these collecting or connecting tubs will hook up with the nefron yeah so the ureic bud forms it's going to meet up adult kidney will meet up with the metan nephos and it must meet up with the metan nephros or no kidney no adult kidney will be formed and the fetal kidney will be degenerating anyway so you may be left with one kidney if you don't get any kidneys that fetus isn't going to survive the formation or the joining of the urtic bud and the metan nephros this happens way down in the pelvic cavity we look at the next illustration we've got the kidneys up by the diaphragm so how did they get there well the body is going to grow very quickly and essentially it's growing elongating faster than the bladder and the kidneys connections can so the kidneys get pulled out of the pelvic cavity and as they ascend they'll be reforming blood vessels and nerves the ascent will end up about the 11th rib the blood vessels that were connecting the iliac vessels to the kidney those will degenerate and then new ones will form off the descending aorta and then just repetitively degenerating after new vessels have been formed so they degenerate and reform as they ascend occasionally you might see multiple blood vessels connected to the kidney as long as they're all working it's no problem it's just an anomaly it's a difference most of the time single artery single vein connecting the abdominal aorta to the kidneys The Meta nephos will form the nephron so the nephros here nephron this will be looping around we have structures called the PCT which is the proximal convoluted tuo don't worry it's spelled out in in later slides our also so a loop the loop could be just described as a nefron loop but often times this epiny Henley is still used so Loop of Henley and then we have a distal convoluted tubal the Bowman's capsule will form around a ball of capillaries that have branched off the renal artery so we'll have a Reno artery entering then arterials and we have an afine arterial that will Branch to form about 20 to 25 capillaries in a little ball and the metan nephos will form a capsule around it we'll see the structures in this chapter the afrine arterial branches to the glomular capillar so we see that term glomus again that means you've got a round structure kind of a balloon like structure in this case the balloon has been punched in by the capillaries so the balloon will be around this ball of capillaries we got a afrine arterial going in and an ephan arterial coming out the so we have Bowman's capsule the capsule is this structure we have a parietal and then we have a visceral covering kind of like the lungs and the Heart the PCT is whoops is that part of the nefron that is the closest to the glus and then there'll be the loop and then a distal convoluted tuio that um distance-wise is farther from the glome capsule but it actually isn't that far anatomically because the ascending part of the loop will come back between the afrine and ephrine arterial so we'll see that don't worry about it for now so we have an afferent meaning going into the glus and an eer arterial coming out they have functional differences that will help us with filtering our blood and creating a filtrate that will be altered along the lengths of the nefron and the collecting system and finally end up dripping into the minor kis as urine peritubular capillaries what is that all about I'm going to change colors we have this ephin arterial coming out and it's going to Branch into arterials that are going to cover the glus and the loop of Henley and this will help help us with secretion and absorption so they're around the renot tubules there are some nephrons that are very long and so the peritubular capillaries um sometimes they're a network and then sometimes they form straight capillaries that follow long nephrons down into the renom modela so we've got arteries veins and arterials got venal we've got capillaries and the depending on the design of our nefron will'll have vasera or nocta so kidneys where are they they ascended usually to the level of about the 11th rib they're on the posterior abdominal so they are primarily retro perianal not g to spill out the whole word don't have room they are covered by my Gray Line here so we've got the parieto perum that's covering abdomino yorta and arvino Caba and then that is continuous with more connective tissue that's surrounding the kidney we have U anterior ROP fascia and we've got posterior Reno fascia that are attaching the kidney to uh other connective tissue like this perah we know fat Pera meaning around the kidney we've got some fat that is also going into this space called the renal sinus and it helps to support the vessels that are entering into the kidney so that they don't get com pressed or twisted and this Reno capsule fibrous capsule it helps to protect the kidney from any pathogens that might get into your peronal cavity so keeps the kidneys well isolated so mostly for the immune immune protection the fat helps keep the kidney in the right position we've got these uror that can't be kink if they're kinked then they can't transport urine to the bladder also the Reno fascia supporting the artery and vein if those get kinked then blood flow can't get to the kidney or get out of the kidney and the kidney will start to fail so we need this connective tissue and that includes adapost support for the position of the kidneys the right kidney is a little bit lower because there's the huge liver in this side of your abdominal cavity and so left kidney will be able to ascend a little bit further over on the left side we see the spleen so we're looking down at the cut now so we cut transversely and now we're looking down and not up since we're looking up this spleen would be on the opposite side would be a mirror image okay the kidney itself this is a cut that is going through the kidneys Rel l a Corona cut and we see the capsule that is on the very outside and then we see tissues that are different we have one tissue that is forming kind of a rim like a rinded on the orange and and that actually the blood vessels are covering this it's has columns that go down towards the hilum where the arteries veins and urer and nerves are going in and out and lymphatics this outer part is called the core Tex so this is your corex and then we have Reno pyramids we've got these structures that are have a broad base and come to a point and those are pyramids in shape but they're also the Medela of the kidney we see the artery coming in the renal artery goes in and starts to Branch it's going to go to individual loes of the kidney so you're going to have the inter between low bar arteries that's the first Branch inter low bar they come up and then they're connected to each other by an arc of artery so this is called the aru label down at the bottom aru artery and the aru artery is going to give off a art um arterial that um actually a smaller artery that's going to go out towards the into the cortex and towards the capsule and these are the cortical radiant arteries between the cortical radiant arteries or veins we have small lobules these cortical radiant are arteries formerly were inter lobular arteries and they changed the term to cortical radiant not sure how far back maybe 8 10 years ago but they didn't change the name of the veins so we have paralleling the inter the cortical radian arteries and in lobular vein so you see the vein and the artery well the cortical radian artery will give off your apine and ephrin arterials and we'll see that on a later Slide the veins will be bringing blood back from the cortex as they pass back through the Mela they will be picking up fluids and and aoms from the Madela they kind of take the shortest route back out there is no inter lowbar vein there are inter lob um lobular veins and then they just go right into the renal vein well see that broken down into a flow chart coming up the passing through the nefron and then down into the Madela so there'll be tubules that will go down into the madala and collecting ducts that will head on down into the apex of the madola and when urine or when the filtrate actually drips into the minor kis then it's urine up to that point before it drips into the minor kis is just considered filtrate and still subject to alteration the Reno fat you can see it inside the renal sinus so there's a space in there that's the sinus but it's really filled with atap POS that helps to support these arteries and veins there's also lymphatics there and there are nerves there when you get from the minor to the major kis that's where these smaller koses come together and form bigger structure then you have a major kalis and then those feed into the Reno pelvis which is kind of covered up by the Reno artery and vein so on this section we see the minor koses and they feed into a larger structure which is a major kis and the major k sees will go into the renal pelvis and then that's your sink that will drain through the urer down to the bladder so you got smooth muscle perosis that will move this newly formed urine down to the bladder so now here the renal sinus is pointed out and it's filled with atopos to support the arteries and veins that are kind of behind all the arrows here where the arteries and veins are going in and out and the UR is going in and out that is your generic pilum so on the right hand side the actual kind of dehydrated and misshaping kidney is here Medela is all the the brighter red structures that have the parameter shape and then the cortex is going to be the paler Brown that's closer to the capsule except where it goes between Reno pyramids so this are called Reno columns and this is cortical tissue that's important because the glami are in cortical tissue not in the Madela nephron loops and proximal and they still convoluted tubios the loops will go into the Medela the proximal might be in part of the Medela the disto might be in part of the Madela but then you're going out into the cortical tissue two again for collecting Ducks the lob is designated by the blue dotted lines and goes all the way out it's about halfway between two Reno pyramids goes all the way out to the cortex including the madala and the cortex we look at a light micrograph here this is a developing kidney so it's a fetal kidney we don't we're just seeing the developing glome the Caps the capsule is not really apparent but we can see all these this Mass round mass of cells that is the glome capillaries with the visceral epithelial cells on them so lot of nuclei there and they will develop a very distinct capsule which we'll see in the mature kidney let's see if we can find some yeah here so here we have this very distinct white space around those glome capillaries with their the cells on top of them got a lot of tubes to talk about we'll come back to that so this is the feto kidney we can see some large spaces and some a little smaller spaces and some even smaller spaces some of these are collecting ducts able done at the bottom they're radiating all the way out to the capsule and then also headed back down into the Reno pyramids so they're coming out you see in the lower left they're coming out of the madala we don't see the madola here and radiating all the way out to the capsule we have GL can also call those Reno corpuses or glomi both terms are acceptable some of these tubules and higher magnification we'll see a difference in the staining paler staining means you've got a collecting duct if it is Pinker the cells have a Pinker cytoplasm it's a straight part of the proximal convoluted tubio gut some complexities here that need to learn about the higher magnification here if you're lucky you get to see a high concentration of nuclei in a tubio and this is called a macula so a spot with dense nuclei in that area this is a very um highly functional group of cells they're looking at the filtered fluid as it passes back past the glome the glus will have the fluid going out in to a tubio that's very pink and has a lot of what I call mushy stuff but it really is glyx in the Lumen going into the proximal convoluted tuo and then a clearer disto convoluted tuo that's coming back past the glus again you find immacula then you know exactly where the tubio has gone between the afrine and ephrine arterial chemicals communicate with apine arterial and cause some release of enzymes that will start the in and ensin aldosterone system so we'll talk a little bit about it in Martini but more in Sherwood we head on down if we follow these tubules and collecting Ducks down towards the left we're going to see them ending up actually opening into uh collect system right now we see a lot of adap POS but we have a little bit of space that's showing up this will be our minor kis so our filtrate will drip drip drip into the minor kis and then into a major and then into the urer right now we're looking at which the artery and vein are entering and leaving the hilum so we've got a thick wall very kind of a little bit scalloped Edge so that a elastic artery there and it's keeping its shape even though there's no blood in it and then the vein which is flattened out and a little bit less round and that's where you you can see some evidence of red blood cells that are still in the vein the arteries with their smooth muscle and elastic fibers when blood is when the tissue is cut blood tends to leave the artery very quickly but there's not as much elasticity on the in the vein so usually you see some red blood cells remaining we have you know cor pusles all almost all the way down to the minor koses and so this is telling us that we're in AR Reno column not in the main part of the Madela so let's look at a [Music] nefron we have two types of nephrons cortical nephrons the majority of the nefron is in the cortex the Reno corus that is your glal capillaries and Bowman's capsule this is closest to the Reno capsule if you're next to the madola urino coroso is down there next to the madola you have a julary nefron these julary nephrons are the long Loop Loops so we see a thin and a thick component to this Reno or nefron Loop or Loop of Henley the first part of it me remove that red the first part of the nefron is the Bowman's capsule and your proximal convoluted tubio the PCT is this component here oops went too far is this component here and we convoluted just means it's going in multiple directions it's bending and twisting on itself then there's a straight component then you end in a narrow part of the nefron loop that's the thin descending limb do the pin turn some Thin ascending and then it branches out the epithelia changes to a cuido which is a thicker part of the ascending limb so there is a short thin portion but then the majority of it is this thick ascending limb that thick ascending limb goes back between your aper and epher arterials in that location changed to Red oops didn't get changed in that location that's where your macul densa will be we look at the Reno coroso in part C we see the bracket showing where the Corp pusle is where the capsular base or Bowman's space is and really the in clinical situations Omens is still very widely used so get used to hearing it you can call it the capsu space but most people will be calling it Bowman space when things get in into the capsular space they have been filtered but now they're going to go into the tuo first part will be the proximal convoluted tubio or PCT get tiresome to say proximal com tuia all the time so PCT for short PCT is identifiable because the cytoplasm of the cuboid epithelium is much more eosinophilic it is much Pinker and there are multiple mitochondria I'm sorry multip well there there are multiple mitochondria for energy but multiple microvilli with glyx and so the proximal compilated tubios Lumen is often filled with that pink mushy stuff that I talked about it's really the glyx when you get to the dto convoluted tubio the they're still cuboidal cells but they're not as eosinophilic they're a little bit flatter this still cuido but people call it a low cuido and the Lumen doesn't have the mushy pink stuff in it because these guys do have glyco CX and microvilli but it's very sparse and the microvilli are very short and there's a lot of space between them so the Lumen is relatively clear in the distal convoluted tubio we go to our thisto conv tubio we see it coming out and heading to connect with the collecting duct the collecting duct is this thicker structure it's labeled over here so I just label it short hand here and coming back up these branches those are are col collecting or connecting here it's connecting but other text would say collecting tubules this is still part of the urer but the minor Kus down here will have come from the same tissue that was making up the lining of the bladder the urer the pelvis and the koses and then some osis happens here still that same tissue is going up and into the metan nephos but no longer the same epithelium it does the epithelium does change the significance of these papillary ducts when the fluid gets down the filtrate gets down to the level of the papillary ducts then you you have no further alterations so no more secretion no more absorption and it's technically urine at this point that will be dripping into the minor kis the illustration makes it look like there's a significant amount of this capillary duct in actual like micrographs it there isn't that much distance so let's look at these this more mature kidney take away our red circle here we have the capsular space that's very distinct now because we have a fully developed kidney have the capsule out to the right side and we see all these Reno corpuses at various levels we also see a lot of interconnecting tubules and then over to the right I've boxed in what are called magary Rays what a magary ray is this tubios that are coming out of the madola and into the cortex so there's some more meary Rays down at the bottom some of these tubular will be collecting ducts some of them will be the you see glyx here so some of them are the straight portion of the proximal convoluted tubio and some are clear so they could be connecting uh or collecting ducts this next illustration we I've pointed out because it's in color you can see the red change color here this is blood vessels so basa repa following the tubules down into the inner Madela so there're the vasar recta are paralleling the collecting ducts so vasar recta collecting duct vasera collecting du and they will get all the way down to the surface here and then drip their urine into the minor kis the epi iium here is a low to a low columnar or tall cuboidal and then on the minor killis side we transitioning to urinary or aka the transitional epithelium we've got minor kis and it's headed towards major kis okay we're going to stop part one here stop part one