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BIOL 3324 Human Physiology - BIOL3324_lecture19_1102
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00:17 Oh, there we go. I'm wired up. Finally. Um,
00:21 you're looking at up here, this the distribution over exam three. I
00:25 there's like one person that still has take the exam, um, due
00:29 an illness. Um, it's one two. I can't remember exactly.
00:34 , so again, you can see the average 65 high grade on the
00:39 , 96 low grade was the 22 deviation. You can see how it's
00:43 spread really, really wide. uh You can do a comparison here
00:48 uh the comparison, uh just shows how the average has kind of
00:52 it's gone. It started off around 60. It's kind of moved
00:56 Um, I'm not gonna do an semester comparison for you all because it's
01:01 particularly relevant. Um, but what guys really care about is this stuff
01:06 here. Um And this is just you what the rolling average is.
01:11 , again, this is after three and a homework assignment. So right
01:15 , a minus sits around an Uh 60 is roughly about where AC
01:20 is. And so that's kind of breakdown. Um And again, after
01:24 fourth exam, those numbers will change this doesn't include extra credit. So
01:28 take whatever your average is that you're it out, add in your extra
01:31 and it kind of gives you a of where you're standing. Uh You
01:34 also add in pluses and minuses if want to, if you're that,
01:38 know, you, you need to just take the diff difference between the
01:42 values that you're looking at divide by . And that kind of gives you
01:45 rough idea. Um, but we have a quarter of our exam
01:49 if you have questions, concerns about , um, scores, uh,
01:53 and see me, I've, I've , um, probably later next week
01:57 than earlier because A and P students , are exhausting. Um, now
02:04 just lots of them and they're freaking more. They, um, I
02:07 I've told a couple of y'all, have an, a many of them
02:09 pre nursing students and they have an over in the nursing school that tells
02:13 if they have a B minus or to drop the class, you
02:16 And so that's just really, really bad advice for a freshman.
02:21 so it's just takes every ounce of . I have to try to kind
02:25 like, say stop listening to these . They're not trying to help
02:29 they're trying to prevent you from doing , what you wanna do.
02:33 but anyway, if you'd like to and talk to me about your
02:36 uh, what they all mean, , what you can do to,
02:38 improve what choices you have, that of thing by all means, I'm
02:42 for you all next week. what we're gonna do is we're gonna
02:48 going into this last unit, this uh, section um, of
02:55 that covers the renal system, the system, the endocrine system and the
03:00 reproductive systems. That sounds like a . Given that most of the units
03:04 looked at so far are two right? So we're looking at
03:10 So there's more, but here's the news. Each of these systems that
03:17 looking at with the exception of the system have a certain type of similarity
03:21 them. All right, they're, I would refer to as tube systems
03:25 a tube system has a beginning and has an end and you can think
03:30 a tube as in, as in happens along the length of the
03:34 right? So it's the way I of think about it is like,
03:37 about a car wash. All you have a car, you bring
03:40 in the front of the car wash then what you do is you went
03:43 the car, then you add in soap and then you brush off the
03:45 and the water and then you add the wax and then you do the
03:49 and all you're doing is you're moving car down. And if you go
03:51 really fancy car washes, they have that blink at you as you go
03:54 the new section, right? And all we gotta do when we're looking
03:57 these systems is say, hey, my tube. Where, what are
04:02 different sections of my tube? What one part of the tube from the
04:07 ? And then what's going on in tube? That's really all it
04:10 And this is true for the renal . We're gonna deal with that
04:13 When we do the digestive system, that, that should be an easy
04:17 for you guys, right? I , the digestive system begins with the
04:22 and ends with the anus is what looking at. So basically, if
04:26 can think of the whole tube, that one long structure? You
04:30 it's like, OK, I just to go through and figure out what
04:32 the different parts are. All And then we'll do the same thing
04:36 the two reproductive systems as well. makes it easier to look at these
04:40 . All right. So renal urinary system is our starting point and
04:46 gonna tell you this not to scare . People have told me you don't
04:49 people this, right? It's in my opinion, the hardest stuff
04:54 gonna cover for this unit. Is renal system and it's not there to
04:59 you panic and freak out. That not its purpose. The idea here
05:01 to let you know is like, , once I get past Renal,
05:04 gonna really get kind of easy as move along, it's the easy,
05:08 system and it's not anything in Like, I mean, the rental
05:11 itself is actually pretty straightforward but there's small part of it that kind of
05:16 out, which we're gonna talk about Tuesday next week. That kind of
05:19 kind of confusing. And I'm speaking my own experience when I sat in
05:23 seats as a, I don't junior in college. First time I
05:27 physiology, I saw that and I like, uh uh I don't get
05:30 . And so I went like la la la la, you can't make
05:32 learn this. And then as a , I took physiology again or post
05:36 , took physiology again and came to kidney. And what did I
05:41 La la, la, la You can't make me learn this.
05:43 then as a grad student physiology one time. And here we are in
05:47 kidney. I'm like la la la , you can't make me learn
05:50 And then I became a professor and had to teach it and I
05:53 I gotta learn this. So, um and once I learned it,
05:57 was like, oh, this is easy. But because it initially seemed
06:04 , I put my own barrier up said I refuse. And so I'm
06:08 to keep you from doing what I and putting your own barriers up,
06:12 put up the barriers. If something make sense, just say,
06:16 stop, this doesn't make sense and try to make it make sense right
06:22 and there so that you can walk her going, I'm the one person
06:26 of the entire history of physiology that the kidney the first time. All
06:31 , actually, I just want you to know more than the people at
06:33 A and mut. So anyway, what we're looking at here is the
06:39 overview of the renal system or the system. Actually, urinary system is
06:44 of all encompassing where renal system kind focuses in on kind of the
06:48 And that's just kind of a nuanced to say it. But we're gonna
06:51 , we're just refer to it probably renal. And so what we're gonna
06:54 is we're looking at the kidneys, is the organ that forms your
06:58 uh from the kidneys. You have two pathways that lead out, this
07:02 the urine away from the kidney once made. Um And they go and
07:06 that material to the urinary bladder. call the urinary bladder instead of just
07:11 because there are other bladders in the and other organisms have different kinds of
07:15 and stuff. But the bladder is a structure for holding urine until it's
07:20 to go to the bathroom. All , because we make urine all the
07:23 2477 days a week. Never All right. So here we're gonna
07:29 that. It's a smooth muscle walled and basically balloons out. Actually,
07:35 used to, uh, back in 17 hundreds and even earlier, what
07:38 would do is they'd kill a pig a cow and they empty out the
07:42 out of the bladder, blow it , tie it off and let the
07:45 play with it as a ball. why they refer to a football as
07:48 pig skin. Ok. Fun things learn in your physiology class.
07:54 And then finally, the tube between bladder and the bathroom is called the
07:57 . All right. Now, in , its sole purpose is to move
08:03 from the bladder to the bathroom. right. But in males, it
08:07 has a twofold purpose. All First being the same thing, bladder
08:10 the bathroom. So, urine passes that. But it's also the uh
08:14 pathway for the ejaculation of sperm during . And it has other materials or
08:21 pathways that enter into the urethra that gonna get to when we talk about
08:24 male uh uh reproductive system. But to kind of give you a sense
08:30 , of structure, that's kind of big picture, the big the overview
08:35 we're gonna spend most of our time here in the kidneys, this stuff
08:37 kind of just kind of like and they exist. All right
08:41 in terms of functionality, what are dealing with? What is the urinary
08:45 responsible for? Well, the primary is what we call conditioning the
08:51 That would be like the overview. conditions the blood, meaning it makes
08:56 to it. So we're going to the blood and we're going to pass
08:59 blood through the kidney, we're gonna materials out of it, meaning we're
09:02 to remove waste products. And then we're gonna do is that filtrate that
09:05 create as we remove waste products from fluid is then gonna be re altered
09:11 that we return things that the body and then we're gonna put new things
09:15 it that the body doesn't want. that is how we make the
09:18 That's the whole process that we're gonna . And then with that material,
09:22 urine that we've created, we're going eliminate it, get rid of
09:26 So the urine is primarily the waste that the body is removing from the
09:31 itself. All right. Now, are other functions and some of these
09:36 cover some of these. We But just to understand that when we
09:39 about the kidneys, it's not just waste. All right. So for
09:45 , um we will make calcitriol in kidneys. You guys know what calcitriol
09:51 ? Have you heard that term? . What is calcitriol? Nodding the
09:55 . She's like, I don't wanna it. Now, do you,
09:58 vitamin, if you had to what do you think? Vitamin
10:05 vitamin D three? All right. plays a role in that, in
10:09 production. All right, it and actually releases erythropoietin in response to
10:17 oxygen carrying capacity of the blood. right. So when kidneys get uh
10:21 enough oxygen, that's the signal to the erythropoietin. We've kind of already
10:25 that it plays a role in regulating ion balance in the body. It
10:29 a role in regulating your acid base . It plays a role in blood
10:35 . All right. And we are talk about that. So that's part
10:38 the reason why we put this right circulatory and respiration because it plays an
10:43 role in maintaining blood pressure. All , also has the potential to engage
10:50 gluconeogenesis. Flashing back to bio one is making up new glucose. If
11:00 don't know, just look at the making new glucose, right?
11:04 and it's from, do you remember ? Huh? What, what do
11:10 , what do you make the glucose anything? Well, we don't do
11:19 . Damn it. That'd make life much easier, wouldn't it? It's
11:23 . It's primarily amino acids, but can also do it from fatty
11:27 In other words, you can live a life of life diet of Cheetos
11:30 you wanted to because you can make the sugars your brain ever needs from
11:35 for the most part. All So when you consider all these different
11:40 , this is what we're saying. we condition the blood, we are
11:44 the composition of blood as blood passes the kidney. That's what we're getting
11:49 . So the first portion of this is going to be anatomy. And
11:53 , we just can't get past it we're dealing with a tube structure,
11:57 structure, we need to understand what tube is. So here is a
12:01 of the kidney. It is the that's responsible for maintaining the stability of
12:06 ECF volume. So that would be , which has an impact on blood
12:09 , your electrolyte composition. So the of ions that you have in the
12:14 , which has an effect on how water you hold in. And so
12:17 your osmolarity and all these things have impact on blood pressure. All
12:22 So what we're really going to be is we're going to be adjusting how
12:26 water and other stuff you have sitting the blood. That is what the
12:30 is. And then we're either gonna it or we're just gonna get rid
12:33 it. That's its goal. So are the parts. All right.
12:37 off, we have two distinct uh we have an outer region that's
12:41 here by this uh pinkish area that be the cortex and then everything inside
12:46 pinkish area is gonna be the So there's our defining two different areas
12:53 can see in our little picture we have the little things that look
12:56 onions or scallops. And in between , we have the space where you
12:59 these large arteries penetrating through those large in between the the scallop onion looking
13:05 , those are called the renal All right, and between the renal
13:10 , these are the renal pyramids. so what the column's purpose is is
13:13 allow for materials specifically to allow blood to penetrate up into the cortex and
13:21 allow to distribute the blood to the that are going to be doing all
13:24 heavy lifting here. All right, pyramids. On the other hand,
13:28 you can see that they're trying to you a sense of that. There's
13:30 striation to it. These are going be little tiny tubules where urine is
13:35 formed. It really at this this is filtrate, but ultimately,
13:38 will become urine. All right. so we have a way that we
13:42 the pyramid. So this flat portion here forms what is called the cortical
13:48 border and that's an important border. right. The reason it's important is
13:53 the environment of the cortex is different the environment of the Mandula specifically when
13:58 comes to the osmo or osmolarity of um areas. All right. And
14:05 will become important in understanding this is of the part that makes it
14:09 The kidney heart is this weird environment ? All right. But again,
14:15 deal with that on Thursday. All . So when you look at a
14:19 , you have a base of a and you have an apex of the
14:22 , right? Yes, I got nodding of the head. Let's see
14:28 over here. Yes. OK. , good. All right. So
14:32 we have here is we have the Mallary border that makes up the
14:35 the apex we refer to as the . All right. And the papillae
14:40 basically these tubules coming together and emptying into this region that we refer to
14:45 the pelvis. And so this structure , actually this whole thing right here
14:50 referred to as a sinus. The that's further down is called the
14:54 And what we're doing is we're taking little tiny micro structures and converging them
15:00 to form this larger macro structure. so the macro structure exists as first
15:07 Kyes. And so that's what you're here, these areas here and the
15:12 Kyes converge and form Major Kyes and major calice converges and forms the renal
15:19 . All right, which would be down here. And collectively, what
15:23 doing here is the urine that we're in micro quantities is converging and becoming
15:28 macro quantity. And then what it's do is it's gonna pass down through
15:32 ureter on its way to the Now, the other structure here
15:37 I think on your slides, it helium. And so that is me
15:42 an idiot way back when and never it. Today, I changed
15:45 It's helium is the proper way. not helium, but the helium is
15:49 the region where the veins and the enter or exit the uh a
15:56 And it also includes in this the ureter. So that's just the
16:01 point or exit point in an organ the vasculature is penetrating. And so
16:06 what we're seeing here. So this just trying to show you all the
16:10 things that are penetrating in there. anything that's going in through the kidney
16:14 via the hill. Ok. So not gonna go through the list of
16:20 . Now, that's the macro, the big picture and it's gonna create
16:25 us kind of the environment to where going to be spending our time.
16:29 right, because the structure of interest we talk about the renal system is
16:34 nephron. All right. Nephrons are microstructure that is doing all the
16:41 All right, it is the functional of the kidney. There are hundreds
16:45 thousands of these nephrons, all And so in our little cartoon
16:50 You can see this structure right What did we call that? Do
16:53 guys remember the onion looking thing? pyramid, right? And then,
16:59 over here this would be the right? And so you can see
17:05 this, this artist has just drawn so that you can see two different
17:11 . That's what this this artwork But you can see here now what
17:15 have that are forming these pyramids are of the Nephron, right aspects of
17:21 Nephron. So when we look at Nephron, we can kind of see
17:24 there's actually two parts to it. have a part that is basically a
17:29 portion which we refer to as the corpuscle. And then over here,
17:33 little yellow parts, that's the renal that is a tube. All
17:38 This is where the urine is gonna made. So, what we're doing
17:41 we're creating a ju a junction between vascular and the tubular. All
17:47 And so your nephron has these two to it. All right.
17:53 if you look at the picture you can see when I look at
17:56 , the majority of the nephron is out here in the cortex, but
18:01 is a portion that dips its way into the co uh the medulla,
18:06 is what we refer to as the of Henley or in the newer
18:10 the nephronic loop. All right. loop of Henley is, is usually
18:17 you're gonna see it. Now, we're gonna do is we're gonna focus
18:22 on where that junction is. when you guys took uh intro
18:26 did you guys ever talk about like eggs? Ever? No, any
18:31 of development in the, in bio or bio two? No.
18:35 The only reason I bring that up because one of the things they teach
18:38 when you talk about uh the formation like frog eggs and stuff, you
18:41 a vegetable pole and you have an pole and it gets very, very
18:45 , especially if it's your first time doing developmental biology and it's very,
18:48 scary. Right? And what I'm out here is that we have two
18:52 . All right, we have two that are opposite each other when we're
18:55 with, with the renal um uh puss. All right. And
19:01 and the renal tubule, they're just that egg where it's, there's two
19:05 to it. All right. So first half is vascular, the second
19:08 is tubular. And here what we're do is we have, let's
19:13 how do I set this out? gonna look at the core puss
19:15 All right. So what I want to focus in on is this right
19:20 ? You can see we come in the first thing you're gonna see is
19:24 small artery, an arterial. We that the A fern arterial. All
19:29 . And then the aerian arterial creates little network of capillaries where you're going
19:36 be filtering materials out through these And then coming out of this uh
19:41 of capillaries, that would be the arterial. So you have an A
19:46 arterial, a glomerulus and then the fern arterial. So a way in
19:52 way out and in between the this is where filtration of the plasma
19:58 . Now, this filtration is going be very, very specific. It
20:02 allows small materials to pass through. right, it doesn't allow big
20:08 all right, but it allows more than a regular capillary wood.
20:12 what you're doing is you're pushing plasma into this space that is gonna belong
20:17 the tubular portion. All right. that's what you're seeing up there.
20:21 , the turquoise is that the right turquoise? Light, light blue?
20:25 . We'll go with light blue. Let's see. No. Yeah.
20:29 . Yes. So this is Yeah. So you can see this
20:32 the tubular portion which we'll get to , in just a moment. So
20:35 happening is this fluid comes in and gets filtered out through the capillary walls
20:40 the glomeruli into this turquoise area, belongs to the tubular portion that's called
20:45 capsule. We'll get to that in second. All right. Oh,
20:48 guess it's on this slide. All . So the way you can think
20:51 Bowman's capsule is think of a blunt tube. All right. Remember we've
20:55 talked about blunt ended tubes. Where we see our last blunt ended
20:59 Yeah. Lymphatic system. That's that's, I'm, we're shooting for
21:03 things. All right. But here we've done, instead of having just
21:06 blunt tinted tube that begins like, what we've done is we're taking these
21:10 and we're jamming it down into the tinted tube. So it's kind of
21:15 if I can find my little pin here, it's kind of like
21:21 All right. Ready for crappy jo time, crappy drawing time. All
21:25 . It should be like a special of the class. All right.
21:29 if this is my blunt in the again, I apologize because I have
21:32 write on something that likes to All right. So if this is
21:36 blunted the tube and this is my , what I've done is I've taken
21:39 capillary, jammed it in there and my blunt into tube is wrapped around
21:43 capillary. Like, so, did that kind of make sense?
21:48 punched something into the end of this into tube. So what we're doing
21:52 we're getting exchange that's taking place across wall. All right. So the
22:00 inside Bowman's capsule, the very tip that tube is called the Bowman
22:04 And so the materials being filtered through glomerular walls, the capillary walls are
22:11 to enter into Bowman space inside Bowman's . So once you go into Bowman's
22:17 into Bowman space, you're no longer the vascular component. You're now in
22:21 tubular component. OK. So what doing is you're transitioning plasma in the
22:28 , right? It pushes through the wall and now it's in the Bowman's
22:34 and we no longer call, call plasma because it's no longer in a
22:38 vessel. We now call it So what's the difference here? I'm
22:45 Bowman's capsule over here, I'm in glomerulus. That's the difference.
22:52 So far, so good. So the capsule going straight up you
22:57 space in between. So the space we're referring to is the stuff here
23:05 that picture that is turquoise in All right. So that is what
23:08 referred to as Bowman space. This here, this portion that's the
23:15 even as it goes around the edges the, of the uh the
23:22 the, the vascular component that's wall Bowman's capsule. So, what you're
23:29 is you're filtering past a capillary endothelial through some basement membrane and then an
23:36 cell that bel or an epithelial cell belongs to Bowman's capsule. So you're
23:40 crossing across a barrier. All Now, this is possible because these
23:45 really tight junctions, right? There's some cells in there that, that
23:48 deal with and it's kind of like . So if I had put my
23:52 like this can things filter in between fingers. Yes, they can.
23:56 know it's harder when you're back. can things filter between my fingers.
23:59 course. All right. But can things. No. So I'm not
24:03 to lose red blood cells. I'm going to lose white blood cells.
24:06 proteins can't escape. Only small things escape through that. And we're talking
24:10 some really, really small molecule. think the biggest molecule you'll see there
24:15 um like albumin, I mean, can't escape. And if you don't
24:18 what albumin is, it's the stuff makes egg whites sticky. It's a
24:22 protein, but that's too big to pass through. All right.
24:29 what we're defining here then is that on this side of this barrier.
24:37 if that's the barrier, everything on side of the barrier in this
24:41 that would be tubular, everything on side of the barrier, that would
24:47 vascular. All right. So that's of our defining boundary for the vascular
24:53 the tubular component. So we get the renal tube now and this is
25:01 structure that we're more concerned about in of a tube structure because this is
25:05 we're going to make the urine. when that fluid gets into Bowman's space
25:12 Bowman's capsule, what do we call filtrate? Right. So, filtrate
25:18 urine, it's not gonna be urine it arrives in the renal pelvis,
25:23 ? So, way, way down line. And so what we have
25:26 we have a tube structure. And , the artist has drawn two different
25:30 uh nephrons here so that you can the nephrons. All right. And
25:34 gonna keep this a little bit more than the textbook that you guys have
25:39 about because there are some boundaries that things more complicated. All right.
25:47 the first thing from Bowman's capsule, ? You have Bowman's capsule and
25:51 it's big because it has something inside , but it gets smaller. And
25:55 it's a thin tube. In the part of the tube, we refer
25:59 it as the proximal convoluted tubule. right. What does proximal mean close
26:04 or near convoluted, twisted and then , little, little bitty tiny
26:10 All right. So, what we here is we have a tube that
26:14 near Bowman's capsule that goes all over place. And then that would be
26:20 proximal convoluted tubule. Now, you see up here, I have it
26:24 into two things because that's what your does. So there's a convoluted portion
26:27 there's a straight portion. So they to the whole thing as the proximal
26:31 and that's perfectly fine. Proximal tubule acceptable, but typically refer to the
26:36 convoluted tubule. OK. We're gonna the straight part, but it's just
26:41 defining region. So once we go the proximal tubule, then what happens
26:46 is we straighten out and then we dive out of the cortex. So
26:50 our cortical medullary boundary, right? see that because it says cortex and
26:54 below that, it says medulla, ? So that's the cortico medullary
26:59 And look what happens that tube dives into the medulla and that tube then
27:04 a quick hairpin turn and zips back the other direction. So what we
27:08 here is we have a loop. the loop of Hindley. You can
27:12 in our picture, we have two types of loops of Hindley. We're
27:14 get to that in just a All right. But that's the loop
27:18 Hindley. So we have the loop goes down. We refer to that
27:21 the descending loop. The descending loop first. All right. And then
27:25 goes back up the other direction. the ascending loop. So in this
27:29 , a does not begin is not beginning of the alphabet. D is
27:33 beginning of the alphabet descending, then . All right. So we
27:37 turn on ourselves, go right back and we're heading back out to the
27:41 . And once we arrive back outside cortex, then we're going to have
27:45 small region of tube that is all and then it's gonna join up with
27:51 larger tube that then is gonna pass and we're gonna get to that in
27:54 second. But this next region following loop of Henley is called the distal
27:59 or the distal convoluted tubule. All . And that's what we're seeing
28:04 So, all this stuff right here distal convoluted tubule. They're doing it
28:08 and it's shown there as well. gonna embrace all the ink on the
28:12 and color coded everything for you. , what's interesting about the distal convoluted
28:17 is that it forms a structure called juxtamedullary apparatus. We'll deal with that
28:22 just a moment. But I want to just put a little pin in
28:25 right there. So that you know we're gonna be dealing with this kind
28:28 interesting little structure that has a funky . All right. So as I've
28:36 pointing out, we have two different being drawn here. All right.
28:40 there's a reason for that because there two different types of nephrons that exist
28:45 the kidney. We have what are superficial nephrons, what's superficial mean near
28:51 surface. OK. So already it's like, OK, these are nephrons
28:56 are near the surface and really what looking at is it's looking at where
28:59 corpuscle is located. And then what saying is where the corpuscle is
29:03 it's near the surface of the And so typically, when you look
29:06 these types of nephrons, what happens that the loop of Henley goes down
29:11 the medulla, but it barely goes , it just kind of dips in
29:13 comes right back out again and most your nephrons in your body are like
29:18 . All right. So what do have here? I have a
29:19 80%. All right. That sounds enough. It could be 90% it
29:23 be 75%. It doesn't matter. , most of the nephrons in the
29:26 are superficial. All right. One the key features here, that's not
29:30 make any sense because we haven't defined yet is that they lack a
29:35 All right, vas Urrea is gonna important in just a minute. What
29:40 vasa mean? What do you think refers to vascular? Good? All
29:45 . So for, you know, now, you know, it's,
29:48 gonna be something about the vascular that's with this. All right. The
29:52 type is the juxtamedullary nephron. And , we can look at the name
29:56 say, OK, what does juxta mean? Juxta near Mela or
30:01 It's going to be near the All right. So you can see
30:04 , where is this particular core puss ? It's right here next to that
30:10 . All right. And here what have is we have these loops of
30:14 that plunge down deep into the right? They go way down near
30:20 the pelvis is going to be formed the kiss are. All right.
30:25 they're located in different areas and their of Henley do different things. One
30:30 goes in one dies in deep. the other thing that's characteristic of the
30:35 malar nephrons is they do have a ect which we don't know what it
30:39 yet. All right. But that's and it's an important characteristic. All
30:44 . Now, what I have here the bottom of my little list is
30:50 it does two things and why it's important to have these things. The
30:55 is, is that it establishes a osmotic gradient inside the medulla. Let
31:02 explain. All right in your entire everywhere. What is the osmolarity of
31:11 body? Do you remember way back that first unit, way back at
31:15 dawn of time when we talked about . Do you remember the value we
31:20 for your body? It was oh my goodness. You mean I've
31:24 to remember stuff. Yeah, you . It's roughly 300 mill Ozols.
31:30 no matter where you go. If take a little sample of your brain
31:34 fluid, if I take a little of your plasma out of your big
31:37 , if I take a sample of fluid sitting in the cortex of the
31:41 , I would expect to find the area to be about 300 milli
31:46 All right. But in the meduna the kidney, it's not 300 milli
31:54 . Instead, it's a gradient. gradient begins here at about 300 milli
32:00 . And down here at the it can be as high as 1200
32:05 oss. So what you're doing is you are creating a large difference so
32:10 it starts off like the rest of body. But the deeper you go
32:13 , the more concentrated in solu it OK. So what, well if
32:23 exists, it exists for a purpose the purpose here is that, that
32:28 gradient is what your kidneys use to you to make urine of varying
32:36 Let me explain. I, I like I've watched the Princess Bride recently
32:43 something. You know, have you that when you drink lots and lots
32:50 fluids, what color I shouldn't say you noticed? But what color is
32:55 urine? Like if you drink lots lots of fluids clear? Ok.
33:01 all I'm shooting for is clear something like that. If you are
33:07 , right? You've been out in Houston Sun all day long and you
33:10 done the smart thing and consumed fluids you've been going along and you go
33:14 pee, what color is your Bright yellow? Actually, that is
33:21 accurate, but that's fair. You're , OK, that's good.
33:25 it gets darker. Yeah, if are super dehydrated, it will start
33:30 orange and it can go as bad Aggie Maroon. If you see Aggie
33:35 urine, you have issues. I , I'm, I'm not talking like
33:40 like you have. No, I'm like go to the emergency room issues
33:44 what you now have is you have leaking through your kidneys. Ok?
33:48 that's the thing. And so what doing here is you've just kind of
33:53 it's like, look, I got that's watery. So you mean when
33:54 have lots of water, I make urine. But when I am
33:59 I don't allow the water to escape body. So my urine is more
34:04 and ergo much darker than it would had. I drank the water.
34:11 this is only possible because the uh nephrons establish an osmotic gradient that the
34:19 then use to modify the filtrate in of the water solute concentrations. What
34:28 gonna talk about mostly tomorrow is how happened, not tomorrow. Tuesday.
34:33 that happens? The surprise, we an extra lecture tomorrow. No.
34:38 right. So this is really where focus is gonna be a little bit
34:44 . Now, there are other structures here. You can see that the
34:47 convoluted tubules, they converge on another . We call those the collecting
34:52 It's just a small region. Um way you can think about the collecting
34:57 is we have this larger structure called collecting duct. I'm just going to
35:01 a box around the collecting duct and branches off the collecting duct are the
35:06 t tubules to which the distal convoluted connect. All right. So it's
35:11 a very, very small region. so each of these collecting ducks are
35:17 trees to which many, many um are joined. OK. So you
35:27 kind of see here, they're trying show you, look, look,
35:29 lots of these little branches and we're them to show you that they
35:34 All right. So the way we urine is we're going to use this
35:42 that is going to pass through that , which has an osmotic gradient.
35:49 we're going to modify fluid passing through tree structure, the collecting duct to
36:00 whether water stays or goes. Now the collecting dept there are two basic
36:05 of cells here. Uh This is extent to which we're gonna do.
36:08 have the principal cells. The principal are called principal cells because they are
36:12 most common cell. All right, everywhere common. All right. The
36:17 type of cell are the intercalated We're not gonna spend any time beyond
36:21 point. But this is for your A T reviews and stuff like
36:24 Two types of intercalated cells. There's type A and the type B intercalated
36:28 play an important role in managing Ph your body. Intercalated cells are responsible
36:34 eliminating acids. This is the only in your life that words are gonna
36:39 sense right straight up, type A acid type B for base. Thank
36:45 scientists for doing something simple for a . All right. And all we're
36:50 is we're eliminating acids. If Type are turned on, we're eliminating base
36:53 type Type Bs are on. And we're doing is removing things from
36:58 the, the body and putting it the tubule. That's the direct,
37:02 we say eliminate, we're going this . Ok. That's the elimination
37:09 All right. So, so far this all make sense? We have
37:13 vasculature, a fern arterial glomerulus, fern arterial blood passes in into the
37:20 passes out through the E fern filtrate pass through the glomerular walls into Bowman's
37:27 . Into that space. We call Bowman space from Bowman space. We
37:30 through the distal convoluted tubule. Then pass on down through the loop of
37:35 , come back out through the distal tubule. A convoluted tube. You'll
37:40 with the collecting tubule, collecting tubule and becomes the collecting duct, collecting
37:46 empties out into the calice from the to the pelvis, pelvis to the
37:50 , ureter, the bladder bladder to , urethra to the bathroom. We're
37:55 one big long tube, man. tough. Doctor Wayne, you just
38:00 through that really, really quickly draw straight line, put a tube side
38:04 each side of it and just label the way, doesn't have to have
38:07 same shape. It's a tube. right. Now, I mentioned
38:13 the juxtaglomerular apparatus, the next to mela apparatus. Well, what is
38:19 ? All right. So, remember just did something really weird up
38:23 And you probably like, why was doing this? Making these crazy longhorn
38:28 ? I had an aer arterial. had a glomerulus and then I had
38:37 , and then I had the proximal tubule. Then I did my loop
38:42 Henle and I came out and out side. What do I have distal
38:47 tubule? But it's not that simple in the body, this is how
38:52 looks. You see that got my fern arterial, my E fern
38:58 right? And here's my distal convoluted going in between them. Do you
39:05 that it's up there in the A fern and E Ferran out distal
39:12 tubule between them. All right. basically, the filtrate is going all
39:18 the place coming back around and it up here and what the juxtamedullary apparatus
39:25 is that it is responsible to regulate that filtrate is going to be
39:30 It is responsible for managing blood So there are a couple of things
39:34 here. The first thing is going be associated with the A fern arterial
39:39 I'm going to just circle it. the big giant cells that are light
39:42 in that picture, those are the cells. All right. They're just
39:45 smooth muscle cell that's part of the of the afer arterial, but they
39:50 just sit there and just contract and . Although they do do that All
39:55 . They have two roles. their first role is to manage the
39:59 of blood into the glomerulus. If pressure becomes too great, then what
40:04 do is they relax and it reduces pressure into the glomerulus. Do you
40:08 what happens? If I have too pressure inside of glomerulus? It
40:14 That's exactly right. That's bad. in the body is generally bad.
40:20 . All right. So the idea is I'm going to reduce pressure one
40:23 or the other. Actually, I relax. I constrict, I prevent
40:27 flow of blood into the glomeruli. right. So that's number one is
40:31 blood pressure. All right, it change size in response to being stretched
40:37 be a sympathetic stimulation. All So, again, blood blood
40:42 sympathetic stimulation. The second thing that does is that it actually makes an
40:48 that will be released out into the called renin. Right? Renin is
40:53 important regulator of a whole bunch of molecules that are downstream, which we're
40:57 talk about a little bit later that responsible for regulating long term blood
41:03 All right. So Rennin is made these cells. Now, how do
41:07 know when to make Rennin? what I have is I have my
41:12 convoluted tubule and see all the little Gish cells in our little cartoon
41:17 those cells at the distal convoluted, convoluted tubule which pass right there.
41:24 to the Afer and the E fern . The cells that are, there
41:29 the macula denso cells. All The macula denso cells are monitoring the
41:35 of the filtrate through the distal convoluted at that particular point. And
41:40 they're monitoring the sodium chloride that's passing as the sodium chloride passes by,
41:47 expecting a specific rate if the specific is too fast, that means blood
41:53 is too high and I need to it down if the rate at which
41:57 chloride passes by is too slow, means the blood pressure is down and
42:01 need to raise blood pressure. That of makes sense in a really generic
42:05 of way, right? So it's you going out and, and watching
42:10 on 288 if the cars are zipping , that means traffic is going by
42:16 fast. So what do you need do is you need to slow them
42:18 ? That's when you put cops on road to give people tickets,
42:22 But if the cars are slowed down jammed up, that's too slow.
42:26 we need to do something else. open up a couple of lanes someplace
42:29 and get traffic to move that way we can get flow up again.
42:32 there's a response that's occurring because of monitoring the traffic and that's what we're
42:38 is we're monitoring the traffic, but we're monitoring sodium chloride. All
42:43 So there are basically uh channels that sitting there and that allow these macular
42:46 cells to uh to bring in sodium and it's expecting it at a certain
42:52 . All right. So when the chloride concentrations change, I'm going to
42:59 my a fern arterial, I'm speaking the granular cells. So, what
43:04 I gonna tell the granular cell to if it's, if the pressure is
43:08 high? I want those granular cells constrict to reduce the flow into the
43:14 . All right. But the other I'm gonna do is I can um
43:19 if it's going to produce Rennin or . So if the pressure begins to
43:23 , then what I'm gonna do is gonna cause vasodilation. But I'm also
43:26 to say, hey, this is a function of a generalized drop in
43:31 pressure. So granular cells not only , I want you to release
43:36 which will then affect other molecules in pathway that will then raise blood
43:42 OK. Now we're gonna describe those in a moment, but I wanted
43:45 to understand where this is all taking and then there's other cells in
43:49 I'm just gonna raise the slide, the ink on the slide. So
43:51 can see here, let's try that . Um erase all ink on the
43:57 . There we go. You can the little tiny blue cells that are
44:00 in there. Right. Right. . Like there OK, those are
44:04 are called the extra glomerular mesing So, extra glomerular, what does
44:10 mean outside of. So it's outside the glomerulus. So, and their
44:17 cell that means in between cells are of like interstitial cells. Um these
44:22 , are not that well understood if has ever taken a class with Doctor
44:28 . Doctor Dreer studies these kinds of . And so, um uh he's
44:34 moved away from the kidney, but was kind of like he was looking
44:37 , there's, if there's extra glom ones, there's also intra glomerular ones
44:40 they all play a role in regulating . So you can just imagine that
44:43 levels and levels and levels of regulation we're not covering. Ok. That's
44:47 what I want to get at. a dreaded slide. Everyone loves this
44:53 , my goodness. Do I have know all the blood vessels?
44:55 you don't. All right. I a specific point. I'm trying to
44:59 this slide. But when you go medical school, do you need to
45:02 all the names of all the Absolutely. Yep. Lots and lots
45:08 fun. Every artery that ever existed the dawn since man has actually dissected
45:12 human. Yeah. Ok. So I wanna show here is really the
45:19 of blood. So you can see from the aorta. You go to
45:21 named artery, which is your renal . You don't arty divides and you
45:24 see all the divisions here, I'll point to them. All right.
45:27 you can see divisions. These are arteries, you go in between the
45:30 lobes, hence the inter lobal uh then you arc across the tarp top
45:36 arcuate. And then what you do you get down to these little tiny
45:41 arteries, you see, they're radiating , that's, you see where the
45:44 come from. They're just named based what they're doing. All right.
45:48 what I want to point out here that all of these lead up to
45:51 a Ferran arterial. All right. when we learned about arterials, we
45:56 an arterial, it goes into a on the, on the backside of
45:59 capillary, you have a so arterial capillary two vinu. But here we
46:07 have that we have an arterial that this glomerulus, which we said is
46:13 capillary and exchange does take place. on the other side of that glomerulus
46:17 an arterial. Huh? Why? , the reason why is that this
46:25 , the glomerulus is not a capillary exchange, right? We don't have
46:32 and material exchanges taking place. This a capillary that allows filtration to
46:37 It's a modification in the arterial to this to happen. So really,
46:43 can think about it like this, A fern arterial and the E fern
46:46 is basically the same arterial with some of weird mutation on the inside or
46:51 them. Ok. Because on the side of the afer or on the
46:56 side of the E fern arterial, is where you see the capillaries of
47:02 . All right. Names of the that play a role in providing nutrients
47:06 materials and taking away waste from the that make up the kidney. Those
47:11 called the peritubular capillaries. Ok. perry. Next to the tubules,
47:18 capillaries. All right. And notice over here we have the bases
47:25 That horrible thing we haven't mentioned It's not horrible. It's just
47:30 All right. And so what we here, this is where the exchange
47:37 fluid with the surrounding interstitial cells So the glomerulus is not a true
47:46 in the sense of exchange. It's capillary because it's tiny. All
47:51 That's what I'm trying to trying to here. So you don't need to
47:55 all this stuff. I'm just trying show you what a glomeruli actually
48:00 It's not the capillary of exchange. picture shows that a little bit
48:07 All right. So you can see the glomeruli are gonna be. You
48:11 see right up there, right? your glomerulus, there's the glomerulus,
48:14 glomerulus. They're trying to show you little red squiggly line and so red
48:19 line is on either side of the squiggly line is a straight red
48:22 right? So that would be a arterial glomerulus, e fern arterial and
48:26 from your e fern arterial, that's you open up into this capillary
48:31 that's kind of going everywhere, capillary , going everywhere. These are the
48:35 capillaries, all right. And so predominantly reside in the cortex. They
48:42 themselves around the tubular uh cells or uh the tubular components and they provide
48:46 nutrients for all the cells that are that location. So this is how
48:51 cells survive in the kidney. So it's beyond all that stuff.
48:57 then when we're dealing with that juxtaglomerular , look what happens. Here's the
49:03 arterial and it goes down and it back up, goes down and comes
49:10 up. It looks like those long . What are those? I don't
49:15 know what they're called. They're really in the seventies. They come back
49:19 10 or 20 years, but they're long changed the drooping chains and you
49:24 see what do they do? They along the loop of Hindley and they
49:28 , you know, shorter branches. then they, they have these deep
49:31 and they come back up. So , the vas erecta predominantly reside in
49:37 medulla and they do provide the um and materials that those cells are gonna
49:43 down in the mela. But their job is to maintain the odds mo
49:49 that the nephronic loop established. All . Again, we haven't talked about
49:55 . So if the nephronic loop, loop of Henley going down, goes
49:59 and comes back up and creates the um environment of the mela,
50:05 role of the vas erecta is to that, that uh environment is maintained
50:12 though materials are gonna be moving in moving out. OK. So that's
50:16 definition I want you to walk out right now. We're going to deal
50:20 the how later. All right, ignoring how right now and I know
50:25 you want to hear the how right . All right, but I want
50:28 get there yet. So Vasa maintains osmotic gradient established by the loop of
50:38 , which created it. All Peritubular capillaries provide the nutrients for the
50:44 in the cortex so far. Are OK. Thus ended the lesson on
50:53 anatomy of the kidney and the micro of the kidney. All right.
50:58 you need to know all of these parts in very simple terms,
51:03 What does this one do? What this one do? What does this
51:05 do draw out your kidney? Um you want to make your life
51:08 you can do it like this. gonna show you by a nice simple
51:11 . Let me find. Oh That's go over here. Here's my nice
51:14 screen, white screen. Just do like this here. Pen,
51:30 See I put my A fern arterial arterial. Look how easy that
51:36 All right. So What's that? Bowman's capsule. What's this? That's
51:44 glomerulus. I'm gonna put a fern e fern arterial. Does it matter
51:49 one's which? No, as long you know which way blood is
51:53 You're good. All right. What that be? Proximal convoluted tubule?
51:59 is this down here? Loop of ? Which arm ascending? Good.
52:08 over here this still convolute tibial, see, keep it simple. All
52:16 . If you, if you keep simple, it'll make perfectly good sense
52:20 you. OK. Yeah. Mhm the question is, does the filtrate
52:30 through both? The answer is you're right. So each of those
52:35 are independent of each other. So we go back to the tree,
52:38 me just go back to the picture this is a really good way to
52:42 you because all they're doing is showing blood vessels there. So all those
52:45 red dingle balls represent glomeruli. And you can imagine what are those glomeruli
52:51 ? They're forming their own Nephron. blood will just go to whichever Nephron
52:55 receiving them at that particular moment. some blood will go to the juxtamedullary
53:00 . Some will go to the cortical , but you're filling them all
53:05 No, no, it's just It's just you're being driven in a
53:10 . Yeah. OK. Anyone else questions? OK. Key point.
53:22 urine is made by the kidney, is neither altered in composition or in
53:30 . All right. What does that ? Once that filtrate becomes urine?
53:36 other words, gets emptied out into pelvis, right into the Calise.
53:42 cannot reclaim that urine. You cannot that urine. It is what it
53:47 . So all the adjustments, all changes to that filtrate must occur while
53:53 the nephronic tree. All right. you're gonna start with a really basic
53:58 and you're gonna go through and you're modify it. But once it leaves
54:02 through that collecting duct, it is it is. So you can't
54:07 oh, I've got some water sitting that bladder over there with that
54:10 I've made, I can't go and that water back. That water is
54:14 leaving the body. It has no but to go. OK. That's
54:18 that means. The process of making three basic steps just like agent oso
54:29 you. I always like to figure who watched the Disney channel. I
54:35 some people don't, didn't, some did glomerular filtration. So we're gonna
54:41 filtration, followed by tubular reabsorption, by tubular secretion. We're only gonna
54:45 through filtration a day. We'll deal the rest of them on Tuesday when
54:49 get back. So as you are going through your reg, regular
54:54 blood is being filtered in through the . So about 20% of your plasma
54:57 being filtered. This comes out to 100 and 25 mils per minute or
55:01 100 and 80 L per day. , just think about that for a
55:06 . I want you to think when say, think about it, I
55:08 you to think about when you How often do you pee per
55:12 About five times, right? Maybe . If you start counting it
55:16 you'll be like, oh, that's about right. Most people,
55:19 about five times a day. All . Now, when you pee you
55:24 between somewhere between 305 100 mils. right. Roughly again, maybe a
55:30 bit more, a little bit All right. So if you think
55:33 that five times a day and I'm say on average about 300 mils,
55:36 about 1500 mils or 1.5 L per . Now, if you do your
55:42 here, 100 and 80 L per , if you got rid of 100
55:46 80 L of fluid per day, would be dried out in a couple
55:49 minutes, right? I mean, think if I calculate that right.
55:53 four, that's 500 that's 40 You would have no more fluid in
55:57 body. So something must be going . So it's not just the
56:02 that's what the reabsorption portion is. , here, what we're doing is
56:06 taking out 100 and 25 mils that filtering per minute and we're returning 100
56:10 24 mils back to the body. pretty impressive. Right. So what
56:15 are making is roughly about 1.5 L day. And again, we can
56:18 back and do those calculations five times day. 300 mils. Look at
56:22 1.5 L. If you don't believe , get out a notebook. Keep
56:29 . All right. Now, the step is the weird one. All
56:33 . So here what we're doing, dealing primarily with the filtrate in the
56:37 step secretion. What we're doing is saying, oh, we're not even
56:40 to bother with the filtration process. have fluid that is flowing in the
56:45 over in the uh in the blood didn't make it into the tubules.
56:49 there's stuff we desperately want to get of. So we have a mechanism
56:52 actually pull things directly out of the and put them into the tubules
56:57 So this is the process of So, what we're doing here is
57:01 getting rid of things at a faster than we normally would because of the
57:06 . And so they have specific carriers are looking for very specific things that
57:11 us to do this. But it's three processes together that result in converting
57:17 filtrate into this urine, which will secrete. So this is just kind
57:23 showing you what that is, is right. So here we go,
57:26 go in through the afer arterial, going to pass through the glomeruli,
57:29 pressure drives the fluid out of the . We're gonna talk about those pressures
57:34 a moment and you're gonna go, , my goodness. Again.
57:36 Yes. Um, and what you're is you're pushing out 20% of that
57:40 that's passing through that Bowman's capsule. right. So, if we didn't
57:47 it back, bad things would So we're gonna return back the things
57:51 the body wants, your body wants of the stuff that gets filtered because
57:56 is a non-specific act, right? water plus whatever happens to be floating
58:02 it. Can you think of things your body wants that might be circulating
58:05 your blood nutrients? Huh? Good. I heard something.
58:15 What else? What's the most important ? What's the thing that your body
58:19 desperate for all the time here? hunt you. What does your brain
58:22 all the time? Oxygen and Glucose, right? If you have
58:31 in your urine, what do we that? Diabetes? You know how
58:35 figured that out? You'd stick your in the urine and sweet. Um
58:46 , don't you? Aren't you glad have different mechanisms now? Uh
58:52 doctors had it rough. Got a of urine. God help the man
58:58 actually developed a taste for urine. right. So there are pressures just
59:04 we saw with pressures that we were with when we were dealing with the
59:08 . All right. So we have inside the blood vessels, we have
59:12 outside the blood vessel. But because dealing with the tubule, the vascular
59:15 , those are the pressures that we're with. All right. So the
59:19 inside the glomerulus, pushing blood out the glomus, that would be the
59:24 capillary blood pressure, that's not too , right? So it's driving fluid
59:30 , right? It's pushing it in direction. Blood itself has a colloid
59:37 , right? It has plasma the plasma proteins stay within the
59:41 So those proteins are drawing water back the blood, right? So it's
59:47 opposing pressure. This is the pressure says, hey, I want you
59:51 go that direction. OK? And we have Bowman Space. Bowman space
59:56 fluid that's filled into it because of that plasma that has been filtered
60:01 Ok. Imagery time. Have you played with the hose? Yeah.
60:06 right. Hose playing time. You that hose has water going out.
60:10 probably did this as a kid and took that hose and you stuck it
60:13 your mouth. All right. see, I can see the
60:17 right? So you can imagine waters back right into your mouth and you
60:22 swallow some of that water at a rate, right? Look,
60:26 look, look, look right. water is going to pass down through
60:29 proximal convolute tub, but it can't Bowman space fast. Enough. Just
60:34 water can't leave your mouth fast enough down your throat fast enough.
60:38 what happens is the pressure builds up your mouth and then water starts spraying
60:43 on, uh, out of your around the hose, doesn't it?
60:46 maybe even out your nose at which that's when you start giggling and laughing
60:50 having fun. Right. That's kind what's going on here is there's a
60:54 pressure. All right. So this a hydrostatic pressure that drives fluid back
61:01 the glomerulus. All right. So opposes filtration and then we also have
61:09 osmotic pressure or an oncotic pressure. all the solutes that happily escape
61:15 But because really the blood has a oncotic pressure. It has all the
61:21 proteins and Bowman space has none of plasma proteins. It's a negligible
61:25 So we just kind of say it's and we ignore it. All
61:28 But it's something that you have to because it exists. All right.
61:33 all we gotta do now is ask question, all right. How do
61:37 four of these pressures affect filtration? then we get to the math and
61:43 math is gross and icky. All , the net filtration pressure is just
61:47 difference between the outward pressures. In words, pressure of fluid moving outward
61:51 being drawn outward versus the pressure of fluid being drawn back inward towards the
61:57 . So that's the frame of reference the glomerulus itself. So the outward
62:02 , remember what we said it is uh the capillary pressure, right?
62:06 it's the oncotic pressure of the hydros the bone and space, which we
62:10 is zero. The inward pressure is one driving it backwards, the opposite
62:14 . That's the oncotic pressure of the and the hydrostatic pressure of bone and
62:22 . All right, we just do math, You see the math
62:24 And so there's a positive pressure of millimeters of mercury. And so that
62:29 pressure is, what is the driving of pushing blood or plasma or that
62:35 from the plasma into the filtrate? , fluid is being formed because the
62:41 is greater on the glomerular side so . Are you with me? Is
62:50 different than what we said with the ? Thank you. I I I've
62:55 two heads nod or shake. How about on this side? Is
63:00 different or the same? It's the . It's just different names. Don't
63:06 scared of different names. It's the thing. Now, if it was
63:10 that was confusing to you, the time is like, wait a
63:12 I've got a push in a That's all you gotta do is think
63:14 like which direction is the push which direction is the pole going?
63:18 right, that's what these are. oncotic pressures are pulling pressures, hydrostatic
63:26 are pushing pressures. That's what we do. And so what we're doing
63:31 we're pairing the ones going out. it's a push and a pull and
63:36 going in, one's a push and pull and up. Yeah. I
63:42 know. It's someone smart, someone than me came up with the
63:48 you know, and I mean, are a lot of people who are
63:51 than me. Some of us just , I mean, I would just
63:54 to them as osmotic pressures, but sure there's a real reason, but
64:01 just say someone's, if someone's maybe they're just trying to confuse
64:07 All right. Now, the gla filtration rate, that's the speed at
64:13 we filter things is dependent upon the filtration pressure. Does this make sense
64:20 you? The speed at which things passing from the glomerulus to the Bowman
64:26 is going to be dependent upon the driving it? Does that make
64:30 Yeah. So if I increase net pressure, what happens to the rate
64:35 goes up? If I decrease net pressure, it goes down good.
64:39 easy, right? So this is result of, and it's the bad
64:50 here is the pressure of the uh blood pressure inside the glomeruli is the
64:57 driving force. If we go back look at these values, look at
65:02 value that's what this is describing. . That's PGC, right. So
65:08 is the blood pressure inside the All right. So if I increase
65:16 blood pressure, then I'm going to glomerular filtration rate because I've increased net
65:22 pressure. Let me put it another . Does the amount of plasma proteins
65:26 your body change all that much over course of a day? No.
65:29 . So you're not going to change all that much the, the hydrostatic
65:33 of the glome or the of the capsule. Can I adjust that?
65:38 there any kind of means for me really kind of adjust that? Did
65:41 describe a smooth muscle system or anything to adjust that? No, not
65:47 . It's, it stays more or constant. I mean, you can
65:50 it by putting more fluid in there it goes up. But how do
65:53 get more fluid in there? I more blood to get into the
65:57 So the thing that I can change I ha can actively change on a
66:01 by second minute, by minute, by day is allowing more blood to
66:06 into the glomeruli or less blood to into the glomeruli? So that's why
66:09 has the greatest effect. That kind make sense if I shove a whole
66:15 of you into my car, That's gonna have the effect of the
66:19 on the inside. I can take out or I can push people
66:23 That's kind of what we're describing increasing and decreasing pressure. So one
66:30 the things that affect the GFR. , things that are intrinsic things that
66:37 extrinsic. How bland of a definition that things that are inherent to the
66:42 , things that are outside the All right. The first thing that's
66:46 to the kidney is autoregulation. All , renal auto of regulation things outside
66:51 kidney neuro regulation. So that would an um the activity of the
66:56 So uh signals through the nervous system the other is through hormones. All
67:03 , auto regulation simply says, my kidneys want to maintain a constant
67:12 despite the fact that over the course the day, minute by minute,
67:16 change blood pressure right now. What's blood pressure? Like it's low if
67:23 stood up, how is your body respond to that drop in blood pressure
67:28 it's lower, but you need to a higher blood pressure to move.
67:31 gonna happen is you're going body is increase with blood pressure. But if
67:35 did that, what would happen is push a whole bunch of blood in
67:37 kidneys which could damage your kidneys. what is your body, what's your
67:41 trying to do? Trying to respond that change to keep it within a
67:47 range, so that the kidneys just of putter along at their constant
67:52 That's the idea. And so it so through two different mechanisms, myogenic
67:57 , as well as tulle mear which is a very, very
68:02 big scary word. All right. what does it mean myogenic, if
68:06 had to guess without me flip of sw myogenic means muscles? All
68:11 So here is myogenic autoregulation. Notice an if then statement here.
68:18 If this happens, then that OK. That's the key thing
68:24 So what we're doing is we're primarily with the A fern arterial, although
68:29 of the stuff can occur in the arterial as well, but it's predominantly
68:33 the Afer arterial. All right. when the pressure inside the Afer arterial
68:40 , right. So if there is blood pressure drop inside the Afer
68:45 then what's gonna happen is the smooth relaxes which allows more blood to come
68:52 , which is going to increase the of blood flow into the glomerulus.
68:58 right. So let's think about this a moment. All right, if
69:01 blood pressure is dropping in the Afer , that means the blood pressure is
69:06 in the glomeruli, which means my rate is decreasing, right? I
69:11 want it to decrease. I want to stay constant. So if I
69:14 the afer arterial, more blood flows the glomus, if more blood flows
69:19 the glomeruli, what happens to my filtration rate? It increases?
69:24 if I have a decrease in blood , I get dilation. So there's
69:30 then which results in an increase in pressure. And thus, a return
69:35 to the original state, an increase GFR. That's what we're trying to
69:41 here. All right. And the here is saying, look, when
69:45 pressure drops, that's what I'm Ok. The opposite is true as
69:51 . If the blood pressure rises, ? If the blood pressure rises,
69:56 want less blood to come in because going to start blowing blood through the
70:00 and causing problems. So what I'm do is I'm going to constrict the
70:04 Ferran arterial. That means less blood into the meus. That means there's
70:09 pressure inside the glome to drive blood the tubule. So my GFR
70:15 So really what I'm doing is I'm an increase in the GFR and I'm
70:18 by decreasing the GFR and maintaining that pressure. Yeah. Fine Malaina.
70:30 huh. Right. So that's further and we'll get to that in just
70:38 second. All right. But it . So you can see here,
70:41 the next thing, the tar So, so the first thing is
70:46 saying if I see a adjustments or in the blood pressure at the A
70:53 arterial, my afer arterial responds to that there's a constancy to GFR.
71:01 . And what we're doing is we're affecting the net filtration pressure.
71:06 you have to remember there's a connection to net filtration pressure is a function
71:11 the blood pressure inside the glomerulus. right. Well, so you can
71:18 that as well. And so I , I said it's primarily this,
71:22 the other thing you can do, I want to create back pressure,
71:26 can act on the E fern arterial well, right? If I constrict
71:30 eer and toil what's gonna happen to pressure inside the glomerulus, it's going
71:36 do. But the better thing to is not to create back pressure but
71:40 create front pressure so that you're not out your glomerulus, right? You
71:44 just think in terms of delicate don't wanna destroy. That's probably why
71:48 exists. But to your question, about this other space? You already
71:54 about this juxta glomerular apparatus. What this? Well, that's what tubular
71:59 feedback is. All right. So gonna find out sodium chloride is one
72:05 the most important salts in the We're going to spend tons of time
72:09 back to this one. All And so what we're doing is
72:12 we are monitoring, using the macula cells are watching the fluid go by
72:17 within that fluid, you have I'm just going to just call it
72:20 salt right now, right? sodium chloride. And so what it's
72:24 is it's slowly picking it up, right, just at a constant
72:27 So if the sodium chloride comes you know, and you get more
72:33 it, what's that an indicator Well, that's an indication of a
72:39 in blood flow, right, which an increase in the glomerular filtration
72:46 which means we need to make a so that we can bring GFR back
72:52 . And so that's when the macula cells signal to the afer arterial and
72:57 , hey, we want you to so that the GFR goes down.
73:02 we're not just monitoring at the blood at the vascular level. We're also
73:07 at the back end of the tubular , right? But it's affecting the
73:13 same place. The arterial, if sodium chloride levels drop, that's an
73:19 of the opposite right here. What done is not enough, filtrate is
73:25 by fast enough. And so that's indicator that there's a drop in the
73:29 . And so what do I need do is I need to tell the
73:32 arterial to dilate so that more blood into the glomeruli so that I get
73:37 increase in that pressure to drive the faster through the tubule. All
73:44 So that would be the juxta glomerular tubular glomerular feedback through the juxta Medullary
73:50 . Now, there was a time this gets really, really, really
73:55 even where I was explaining it. I'd have students ask me a
73:58 I'd be like, uh and then Gill asked me a question one time
74:03 we both went uh and so I out a slide to make this as
74:09 and as simple as possible. And what this slide represents. All
74:14 So what it says up here, is what we know GFR is dependent
74:17 blood pressure check. Tubular flow rate dependent on the GFR check,
74:25 Because the fluid flowing through the tube depending upon what's driving it forward.
74:28 flow rate of sodium chloride is dependent the TFR, right. So you
74:32 think about this if I have sodium that's in my filtrate, it's just
74:36 move along with the filtrate at whatever it's moving at. So there you
74:39 . That's pretty straightforward. All so far we, we, you're
74:42 me and lastly, the rate of reabsorption, which we haven't talked about
74:48 is more or less constant in these areas. The proximal convoluted tubule in
74:52 loop of Henley. OK. That's . So the only place where we're
74:57 to see reabsorption change is going to in the distal convoluted tubule again,
75:01 we haven't talked about yet, but just putting it up there so that
75:04 know this. So we have a rate at which sodium is moving
75:09 So if we're monitoring sodium, then a good indicator of flow rate.
75:13 , that's all that's saying. And , so it says, look if
75:17 uh glomerular blood pressure drops, that there's a drop in the G uh
75:23 . So the glomerular filtration rate and a drop in the tubular filtrate uh
75:27 rate, that's what, that's all is. So if this, then
75:33 what we described in terms of the , if there's a drop in the
75:37 , that means there's a drop in sodium passing by. And so all
75:42 little steps I just described are taking . So if you increase the GB
75:47 , then you'll see all the So if I see a drop in
75:52 P, I want to increase GB . And in doing so I will
75:56 sodium flow. And so the monitor I'm monitoring, which was slow to
76:01 with is now faster. And so made the proper adjustment and then you
76:05 take the whole thing and flip it the other way. If I see
76:08 increase in GB P, then what want to do is drop GB
76:12 So if you're trying to understand this you get lost tonight or tomorrow or
76:17 weeks from now, this is a you come to and you say,
76:21 do I know to be true? then you say, OK, given
76:26 to be true, then this is I explain it to myself. That's
76:30 this slide is for. All this is where we come back around
76:38 say, where is this all taking ? Ju glomerular apparatus, macula denis
76:44 put it into context. A fern , a fern arterial glomerulus, proximal
76:54 tubule, lupa Henley, distal convoluted . And where are those jual
77:02 This is the Jual Marar apparatus. , where are the macula denso cells
77:07 there? Ok. Easy peasy. right. That's where we end the
77:14 when we come back. So, be clear, what is the
77:18 filtrate is everything that is being pushed the, from the glomerulus into the
77:27 . There's lots of fluid there, done no modifications, there is
77:31 there is oxygen, there is there is non waste, there is
77:36 and there's so much stuff in there our body wants to keep. So
77:39 next two steps are going to be modify that to get it back
77:43 We're just getting rid of the stuff don't want. Have a great
77:50 If you want to come talk to , I'll be available all next
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