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BIOL 3324 Human Physiology - BIOL3324_lecture16_1019
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00:02 All right, y'all, we're going start where we left off. We
00:05 talking about hemostasis. That's the really word for saying, making blood
00:10 And we said we had this plasma protein, prothrombin, prothrombin is just
00:15 circulation. And then something happens, ? We either damage a vessel or
00:21 will happen is we can damage a and we'll use either an intrinsic or
00:25 extrinsic pathway and that will activate uh the prothrombin activator which will turn on
00:32 . Basically take that prothrombin cleave it create this protein and that protein does
00:37 whole bunch of things. And there's different things that it does. You
00:40 all that fun stuff? And then said, no, no,
00:43 please wait. We got one more , please wait, wait. And
00:45 do you remember? Yeah, this why I hate ending like that because
00:50 have to review and because the next explains how we regulate all that stuff
00:58 I'd rather talk about something else. you rather move on? Wouldn't you
01:02 get past this? You know, person says, yes. OK.
01:08 when thrombin gets activated, we need regulate and prevent it from going out
01:13 control. All right. So there a couple of ways that we can
01:15 this. We're gonna do this either a per way or we're gonna do
01:18 in an uh through anticoagulants. And when we talk about Peric, we're
01:23 like things like endothelin or uh nitric , not endo excuse me, uh
01:28 . And in essence, what you're is you're basically saying, hey,
01:31 uh while you, you're activating we understand it's important to activate
01:36 but we don't want you to activate because if you did, then all
01:40 blood would turn in one big giant and that, that's just totally
01:44 right? So the idea of the being released is to prevent the activation
01:50 platelets, which would keep that cycle bigger and bigger and bigger. All
01:54 , same thing with the nitric It prevents the platelets from aggregate and
01:59 clots in places that those clots shouldn't formed. Right? So that's how
02:03 limit where that activity is taking place at the site of damage. All
02:08 . And then there are other factors the anti coagulants. There's a whole
02:12 of them. I'm just, I used to make you guys learn
02:14 all. You don't need to learn all now. But anti coagulants are
02:18 other factors that are going to prevent steps in that pathway from happening.
02:23 so this is how you block a from forming it through an anticoagulant.
02:31 the thing is, is that a clot, you know, a scab
02:37 the surface, blood clot internally is something you want permanently. Would you
02:42 with that? I mean, when get a, when you get a
02:44 you want that scab there forever. , it's gross. And icky.
02:48 they're fun to pick. So, know, and that's what I do
02:51 I just pick at them and then they go away and then I get
02:54 because I got nothing to pick But for the rest of y'all who
02:58 normal humans, um you want this to just be there for a short
03:02 of time. Its purpose is simply cl the flow of blood. So
03:06 blood stays in your body while the repairs itself. And so because it's
03:11 temporary structure, we want to destroy as soon as we are able to
03:16 the mechanism to do so is already in the blood. So just like
03:21 have prothrombin circulating around and when we it, we get the thrombin to
03:27 making uh go through this process of . You also activate a factor downstream
03:35 already in the blood plasminogen. Plasminogen a plasma protein. And when it
03:39 cleared by thrombin, what ends up is. So I think that's where
03:43 catalyzed. Yeah. Uh uh what this does is it serves as
03:49 , the mechanism to break down the . And this stuff actually gets activated
03:55 early on and it works almost The difference is, is that the
03:59 at which it activates and works is than the rate at which you're actually
04:04 clot. So you can think it this, I start making clot,
04:09 start breaking clot, but I make faster. So I break it
04:12 And so it takes a while for to break it down. And this
04:15 your body an opportunity not only to breaking down the clot, but it
04:20 . So in such a way that the tissue itself to start repairing
04:23 which is kind of cool, So a scab will go away on
04:27 own, won't it? Right? doesn't depend upon you going into the
04:31 and getting the s tissue all soft falling off. It will slowly disappear
04:35 time. OK? And that's because is there to do that.
04:39 this is also regulated um externally. it's not just the presence of,
04:44 plasminogen, you know, becoming I I have it through the tissue
04:49 activator or through uh urokinase. So , depending upon which way you're doing
04:54 . So basically, the tissues are , hey, um start breaking down
04:58 clot or there's stuff in the blood says, hey, start breaking down
05:01 , but it also has regulators that up and slow or really slow things
05:05 and that's what the bottom list And again, I'm not so
05:08 just know everything is regulated. I these things out because the truth is
05:12 everything you turn on has to be off and everything that turns on something
05:16 gets turned off by something and everything gets turned off, you know,
05:20 turned on. It's just molecules upon upon molecules. So that is how
05:26 were gonna summarize Tuesday and I spent minutes talking about it. All
05:32 today, we're gonna continue on. we've talked about two parts of the
05:40 system. First part was the second part is the blood. And
05:50 they said there's a third part, the third part vascular church? See
05:55 up there on the tree. All . So we've already mentioned these because
05:58 really hard to have a conversation about of the cardiovascular system without actually talking
06:02 them. So we said, we got arteries, we've got
06:04 we got capillaries, arteries, thin , uh away from the heart,
06:07 capillaries where exchange takes place veins is blood is returning back to the heart
06:14 as a simple rule. All But with that in mind, we're
06:18 going to dive a little bit in . And so if blood is leaving
06:21 heart, one of the things that doing is it's coming across this
06:25 uh or sorry, the blood when leaving the heart you're going through a
06:28 of contraction, rare faction. So this period of time where the heart
06:32 actually relaxed and not driving the blood , right? So you expect your
06:37 to behave like the heart behaves, is like push, stop,
06:40 stop, push, stop. But your heart do that or does your
06:44 do that? No, it doesn't it? And so the reason
06:48 able to flow is because arteries have couple of different roles. The first
06:53 is to get rid of that pulsatile , but also to store up the
06:58 in the pulse and to use that to drive the blood forward so that
07:04 can continue to move forward forward even the heart is in relaxation where it's
07:10 diastole. All right. So one the characteristics of the arterial side of
07:15 vasculature is that arteries are considered to the pressure reservoir and reservoir, excuse
07:23 . And specifically what we're talking about are the elastic arteries. The elastic
07:28 include your aorta and the pulmonary the pulmonary arteries, right. So
07:36 the heart contracts blood is sent to aorta, we're just gonna sit on
07:41 left side of the heart, So what happens to the aorta like
07:45 balloon? And now that energy is in the elastic portions? And so
07:50 we do is we slowly squeeze that forward and it moves forward as a
07:55 of that energy is stored away when move on to the next level.
07:59 really what we would call the named , what we have here listed as
08:02 muscular arteries or distributing arteries here. we're doing is we're getting rid of
08:06 pulsatile nature. So notice the elastic still exist pul in a pulsatile
08:11 We have that cysto and that Diaco and over again. And we had
08:16 tree that we showed you where it like up, down, up
08:18 but the curve slowly went downward. you remember that tree? I don't
08:21 a picture here. So I'd have go clicking back backwards. So when
08:26 blood starts entering into the muscular art , what they do is the,
08:31 difference between cysty and diastole begin to reduced because what you're coming up against
08:36 resistance. You're going from big tubes small tubes. And so when I
08:42 to a small tube, right, radius, when it goes down,
08:46 happens to resistance, it goes up when it, when resistance goes
08:50 what happens to flow starts going All right. So that's what we're
08:57 to see here is we're gonna see vasoconstriction, vasodilation to regulate the flow
09:03 blood change diameters. So when we're about blood pressure, we're really starting
09:09 talk about these vessels right here and continues on down even further. This
09:14 the arterials where you really see the of that pulsatile nature where it becomes
09:19 smooth flow. And really what you're with now is this flow into the
09:25 and you can regulate pressure by changing vasoconstriction, vasodilation. So someone with
09:34 blood pressure, this is where the are going to be acting. For
09:37 most part, with regard to the . We're gonna go in a lot
09:40 detail here, but all we're doing vessels of exchange. We're gonna be
09:44 um materials between the blood and the . That's gonna be the latter half
09:49 our our unit here, which is be the respiratory system. So,
09:54 cardiovascular system and the respiratory system, go hand in hand. All
09:58 And the other place where we're making would be between the blood and the
10:03 , right? And so really the vasculature kind of serves as a middleman
10:08 the external environment and the internal environment the easy way to think of it
10:12 that your cells are trying to get and glucose. So external environment,
10:17 getting glucose from the external environment, ? Are you getting your glucose from
10:20 external environment? Yeah. OK. you getting your oxygen from the external
10:25 ? Right? But does your big the cells in your big toe?
10:28 they have access to the external environment do that exchange? No, they
10:33 . You have to get that material the digestive tract and from the
10:37 So that's why we have the capillaries serve as that or really all the
10:41 to serve as that B man. last bit is the veins of veins
10:44 there to collect the blood from the . So after exchange has taken
10:47 we're gonna gather up that blood and just basically convergence. So small vessels
10:52 bigger ones, become bigger ones. um their organization isn't as distinct as
10:58 you're gonna see in the vascular tree the arterial side. And typically,
11:02 is how it's drawn, understand that don't have arteries just on the right
11:05 and veins just on the left side vice versa, the arteries and veins
11:10 right next to each other on And then, but we typically
11:15 think in terms of the circulation. that's why they draw it this
11:19 Um What you have is you have really, really tiny veins, these
11:22 be viols and then they grow and the larger veins. So they'll be
11:26 veins and larger veins. But we really distinguish between the two in terms
11:30 structure. All blood vessels have the structure. And what we're doing is
11:34 just asking the question, is this existing or not existing? But how
11:39 of the structure do you have? we're basically saying zero to some
11:44 So if you have zero, it exist, but you can imagine that
11:48 would be there. All right. I'm not gonna ask you to memorize
11:51 this stuff, but it just shows the differences. And so you can
11:54 here all blood vessels have an So they have this, this uh
11:59 of, of epithelium that makes up inside of the lumen. And then
12:04 you do is you work outward. so here, what you'll see is
12:07 see elastic connective tissue, you'll see muscle, you'll see a stiffer connective
12:12 involved. There also be uh sometimes the larger structures, you'll see that
12:17 the connective tissue, you'll have blood as well as nervous tissue as
12:22 All right. So like for your aorta is fairly large,
12:28 So inside you'll have on the most portion will be endothelium. And then
12:34 you'll see is smooth muscle and elastic tissue. So, elastic connective tissue
12:39 the vessel to expand the connective tissue the muscle allows you to vasodilate or
12:45 restrict, but there's not a lot be able to do uh do
12:48 And then you have more collagen to of create a point of resistance so
12:52 the structure doesn't stretch too far and or rip or tear. Ok.
12:58 that would be kind of the way you think about this. And as
13:00 move further down the list, so go from aorta to the uh arterial
13:05 what happens is that the lumen gets relative to the surrounding tissue. So
13:13 you'll have more muscle and more connective uh that make up that wall relative
13:20 the size of the women. So ratios uh get different. That's what
13:24 picture is trying to show you. you can see here, like look
13:28 the arterial versus the medium martyr. you see why we have so much
13:31 resistance, even if you had the size tube, you know, do
13:36 see why we'd have greater resistance because be more stuff to overcome? There's
13:43 , more inward pressure than outward Um, the smooth muscle there to
13:50 size, which we'll see is rather as well. And I, I
13:54 mentioned the outer, outer stuff. let's get down to actually what they
13:57 do. All right. So pressure reservoir, they're the ones that
14:04 driving the blood forward. That's right? So your heart is just
14:09 the work to create the pressure so the aorta can do its work.
14:15 gonna pick on Sammy for a You took my class in Comparative Anatomy
14:19 we looked at the cardiovascular system of sorts of different vertebrates. Do you
14:23 like this is where I'm picking Do you remember the heart of the
14:28 ? How many chambers did it Do you remember this is the hard
14:31 ? Huh? It was like one a pseudo chamber and then you move
14:36 to, to the next structure like and it had two chambers and then
14:40 move on to amphibians. It had chambers. The idea here is that
14:44 pressure that needed to be overcome or be produced to, in order to
14:49 nutrients and materials to the rest of um, uh to the organism had
14:54 become greater and greater. But in case of the fish, what it
14:58 had that one chamber, it had false chamber which was basically an aorta
15:02 behaved like a chamber. You kind vaguely remember that, just nod your
15:06 and said of course, II, remember everything, right. Yeah,
15:09 . See. You know. So idea here is the heart isn't doing
15:14 the work, the arteries are doing lot of the work, right?
15:19 heart's providing that pressure. All So this is a pressure reservoir.
15:25 pressure is stored in the uh in artery, right? This is in
15:31 to the vein, right? I , I'm gonna point out we're going
15:35 show that the vein is a blood . All right. And I'll describe
15:40 in just a moment, the arterials , and the smaller named vessels are
15:45 be the major resistance vessels. When vessel gets small, you get greater
15:51 . All right. That's the key here. All right. So when
15:55 vasoconstrict or vas or shoot vasodilator, , what I'm doing is I'm changing
16:01 degree of resistance. All right. so when I increase that resistance,
16:06 gonna create greater, you know, I'm gonna create greater flow or
16:12 I'm gonna, I'm gonna in interfere flow. We're gonna see how it
16:15 flow here in just a moment But I'm going, if I create
16:18 resistance, I'm gonna get less flow that vessel. So I have to
16:21 more work to make that happen. right. Um We can adjust these
16:28 independently. We're gonna go into more about this. So for example,
16:31 not gonna get widespread vaso constriction or , you're gonna change a vessel diameter
16:37 this level to meet the needs of body. And then when you get
16:42 even further from the arterials, which the like the tiniest arteries, we
16:46 to what is a kind of an but not quite an artery. So
16:50 call it a meta artery or meta . So this is part of the
16:55 bed and this is what this picture trying to show you here. So
17:00 is the meta arterial. Here's your . You can see it still has
17:03 muscle associated with it. But when get down to the meta arterial,
17:07 is um a structure that works its into a capillary bed still has some
17:12 the characteristics of the arteries, but all of them and associated with them
17:17 some smooth muscle. But where that muscle is located is at the uh
17:23 capillaries are extending from these structures and types of, of smooth muscles serve
17:28 a sphincter and determine which way blood gonna go. All right. So
17:34 precapillary sphincters are using to direct blood the capillary bed and deciding. All
17:40 , this area needs blood. Open the cap, open up the sphincter
17:44 goes in that way, close up sphincters over here, blood doesn't go
17:47 this area. So this is how distribute where blood kind of goes.
17:50 kind of, it's kind of Now, the other half of,
17:54 this is um the throughput channel or thoroughfare channel. That's what this is
18:00 . So this whole thing is in meta arterial, once you get to
18:03 Venus side, it's, it's a structure. Um and it just is
18:08 equivalent of the meta arterial. And don't think I talk about it
18:12 but you can see it has sphincters well and it serves its function similarly
18:19 the opposite side, I have an . I hope so. In
18:27 you never know what an artist has here, right. So in,
18:30 principle, the idea here is arterials up in the meta arterials which open
18:35 in the capillary beds which return back the thoroughfare channel, which go into
18:39 . All right. So that's the way we say that could a capillary
18:44 from an arterial probably, right? it going to necessarily not necessarily,
18:50 just when you get down to this . Just understand we're now dealing with
18:55 itsy bitsy, teeny tiny, very scientific terms. Um,
19:00 right? And we regulate flow through through these with these sphincters. All
19:08 . So I, I don't think distinction right there because that's what you're
19:12 to. Right. Yeah. they're com yeah. So typically we
19:20 say met arterial and again, I met arterial is kind of a generic
19:25 to kind of say not quite an artery or sorry, an arterial but
19:30 a capillary. It, it's in . All right. So arterials little
19:39 , all right. So they don't all that much. That means they're
19:41 , very resistant, thick layer, muscle, they can go through
19:45 vasodilation just in case you don't know those terms mean. Vaso constriction is
19:51 the vessel narrow, vasodilation is making vessel wider. All right now gotta
20:02 sure it's up on the slide. I'm not pret talking here when we
20:07 about the vasculature, vasculature for the part have only sympathetic inner or vascular
20:17 innervation. OK. So when we're about vasoconstriction, vasodilation, we're asking
20:24 the degree of sympathetic stimulation, So if I increase sympathetic activity,
20:31 get vasoconstriction, if I decrease sympathetic , I get vasodilation, right.
20:39 this is like one of these weird where you don't have a sympathetic versus
20:46 is what I'm trying to get at . Right. The other thing that
20:50 have is they have a self induced activity. So they don't have to
20:55 the nervous system tell them what to . They don't have to have
20:59 telling them what they do. What if is when blood flows in,
21:03 feel that pressure and instead of they resist the stretch and they
21:10 So that's the self-induced myogenic activity. right. So all of these
21:17 So we're gonna talk a little bit the nervous system controlling. We're gonna
21:20 a little bit about hormones, But understand that there are different levels
21:25 control. There's local control and beyond control. All right, there's an
21:31 as well as a nervous form of . Now, in your body,
21:37 said that there is a finite amount blood. All right, about five
21:43 on average, just across everybody, towards men, 4.5 towards uh uh
21:49 . Um And when you're sitting around nothing that blood is gonna be more
21:55 in what are called reconditioning organs. rather than in circulation. In other
22:01 , at all times, do not me at all times. All of
22:04 blood is always moving. Nothing is sitting and hiding someplace. All
22:09 So your blood is always always But we have organs that receive more
22:14 than they actually need to receive. then we also have structures that when
22:19 blood is in them, they stretch And so the flow of blood through
22:23 areas slows down. Now, reconditioning is one of those organs that receives
22:28 blood than it should. All So these are typically organs that provide
22:34 and or remove waste. And so can kind of look here at this
22:38 at rest and you could see, , where is my blood going?
22:43 ? And so it's like, look, my kidney is receiving 1100
22:46 per minute. Wow, it's receiving of my blood. If, when
22:50 just sitting around doing nothing. What my digestive system? 13 mils per
22:56 ? Wow, it's, it's receiving about 20% of my blood.
23:02 when you start running, what's gonna is, is now you have structures
23:07 need that blood. When you're what structure needs blood, your
23:14 right? And so your muscles, you look in that top picture is
23:19 is receiving roughly again, 20%. you're now having to do work.
23:24 so you're gonna need more oxygen delivered those muscles. You're gonna need glucose
23:28 . Those muscles are really fat delivered those muscles. You're gonna need things
23:33 they can get their energy and that necessary to do their work. So
23:37 means you need to deliver more but you have a finite amount of
23:41 inside you, right? Five So what we're gonna do is we're
23:44 do two things. We're gonna speed the rate at which blood actually shows
23:48 and we're gonna shift where that blood coming from. So what we do
23:52 we reduce the amount of blood going those reconditioning organs. So we basically
23:59 in each case and that blood is being shifted away from reconditioning organs and
24:05 sent to those structures that need those . So you see what we're doing
24:11 is we manage the flow of blood move that blood to where it's
24:16 Does that kind of make sense to ? Right? Put another way.
24:22 I see the furrowed eyebrow, you two bank accounts, bank account where
24:27 save money and a bank account where spend money, right? You wanna
24:31 something, let's think of something you buy. It's gotta be big but
24:37 house. Oh my goodness, you buy that house. All right.
24:41 you have money in savings that will you put down that down payment.
24:45 don't have the same amount of money your checking account, but the only
24:49 you're gonna be able to write that is because your saving account doesn't have
24:53 check. What do you have to is you have to move the
24:55 don't you? So that's the same that's going on here is I am
25:00 money from one place to the other that I can do the activity that
25:04 wanna do. I wasn't thinking so I was thinking more like,
25:08 , I don't know, a a Frenchy puppy, you know,
25:13 like that. I don't know. guess they cost a lot. I
25:16 seeing signs everywhere. Oh, Yeah. Puppy, I see Frenchy
25:21 for sale all over the place. some puppy mill that is pumping out
25:25 puppies or, or French bulldogs all the place. All right.
25:30 the idea here behind reconditioning organs is when I need blood flow during
25:35 I have a reservoir of blood that be shifted from that structure to be
25:42 to supply more blood to those other . I'm not increasing the amount of
25:49 in my body, but through regulating flow and where that blood is going
25:55 , I'm able to move more materials the structures in need. Ok.
26:00 the idea. Have you ever wondered you take physics as a biology
26:08 Yeah, I mean, I see hit one going up and down.
26:11 like man physics too, especially, ? When you're dealing with optics and
26:17 know, circuits and oh my goodness suck. All right. Things in
26:22 pa things in series because your body basically a series of structures in
26:29 And so if you understand how it in electrical circuits, you know how
26:33 works in the body. That's what see here. So we're going to
26:38 it simple for you so that you go and take physics and tell Doctor
26:43 easy. All right. What you're at here is the example of what
26:50 in the aorta relative to some of named uh arteries that are coming off
26:55 . If my heart is pumping a amount of blood, then the things
27:00 have to receive the same amount of . Does that make sense another way
27:06 put it when I'm in traffic and all in one lane, we're all
27:11 to go the same rate. But then when I open up,
27:15 can, I have access that can of them, each of these cars
27:19 go into, we'll still go the rate. But now we can,
27:22 basically dividing. That's actually a terrible to put that. It's basically
27:27 It's like, uh, the example always used is 2 88 you know
27:31 2 88 and 59 and 45 all together and it's that nightmare hell,
27:35 begins around 6 a.m. and ends around p.m. You all know what I'm talking
27:39 . Right. And so basically you from like seven lanes down to one
27:43 , right? And everything just comes a halt. Right. That's kind
27:47 the same thing. You got these lanes, even though you have different
27:52 going in different directions, everyone jams because you have to slow down because
27:58 smaller lanes and that's kind of what's on here. Everyone can go down
28:02 own lane. So like when blood leaving hard at four liters per
28:06 which is roughly the rate. Think fast that is. That's almost all
28:10 traveling through your body every minute. right, when I get down to
28:15 smaller vessels, all the vessels that branching off, that main vessel has
28:21 accommodate all that blood four liters per . So each one of them are
28:24 in this particular case, since they're the same size, it would be
28:28 of them get one liter per That makes sense, right? But
28:34 they're not all the same size, still have to accommodate the four liters
28:37 minute, right? So look down at the bottom here, I've reduced
28:43 size by three quarters. So I'm getting a quarter of a liter per
28:46 . So all the other blood vessels to dilate and accommodate that extra three
28:52 . So they each get an extra . But the part that goes in
28:56 the part that comes out is the four liters per minute is four liters
29:01 minute. And so you can see what the arteries are doing,
29:05 Why does, why are the arteries vessels because they're smaller and that blood
29:12 to move through them. And they're saying, no, you can't,
29:15 not enough space for all of you come through. So you basically slow
29:19 . But ultimately, if you look all the blood vessels that are being
29:23 off, they're moving the same amount blood. And that's one of the
29:27 that's really hard to think about when think about the cardiovascular system is that
29:31 is in motion all the time. if I'm moving blood into the arteries
29:36 blood moving into the capillaries. And if I'm moving blood into the
29:41 is blood moving into the veins. . And if blood is moving into
29:45 veins, it's blood moving into the , you see it's all connected
29:49 So any effect that you see upstream what you're gonna see downstream. Even
29:54 we kind of say we're just focusing on this part right here. So
30:00 point here that I'm trying to make the flow through each of the individual
30:04 is gonna be based on the resistance they're producing. So flow equals.
30:11 you remember the equation delta P over ? So if I want to increase
30:21 , I have to make adjustments to , to the pressures, don't
30:25 There's a, there's a direct So I have to increase my pressure
30:31 , right? That would be the . So if resistance in one ve
30:36 is gonna be increased, I have or like here, here's the resistant
30:41 , I'm going to have to increase in all the other ones, I've
30:45 to change the pressures to allow that happen. There is a direct relationship
30:52 everything is running in parallel, in their vessels, one vessel becomes
31:00 , which becomes eight, which becomes , which becomes millions. You want
31:10 see something weird. Wait till we to the capillaries. It's gonna be
31:13 kind of interesting here. All Now, that is actually the next
31:16 is capillaries. There are three basic of capillaries. 90 plus percent of
31:21 capillaries are going to be what are continuous capillaries. Very, very
31:24 endothelium, simple basement membrane. And about it. All right. And
31:31 what you're seeing here. These are in your skin and your muscles.
31:35 have tight junctions, but these tight are not really strong, tight
31:39 They're leaky tight junctions. The way you can visualize this is imagine a
31:43 of marbles in water. You take hands, you go down to
31:47 you pull your hands out, stay in your hands. Water goes
31:52 between your fingers. So you can't the tight enough junction between your fingers
31:57 prevent the water from escaping. All . So that would be an example
32:00 a leaky tight junction. All So they're not properly joined, they're
32:05 enough, but they hold the big in. But all little tiny things
32:09 sneak in between the cells moving up level to leakiness. What we have
32:15 the fenestrated. These are in places the kidney. All right. And
32:19 , what you can see is that have more holes more gaps in our
32:26 . So over here, you can pores, right? And this would
32:30 the formation of uh exocytosis or, , or vessel being formed that goes
32:35 the length of the entire uh cell makes up that, that endothelial
32:40 All right. So here you're gonna more of them. And so there's
32:43 permeability. You still have a basement , right? And your leaky junctions
32:49 leaky still. So here you're gonna more things being able to escape.
32:55 you can imagine again, like in kidney where I'm going to be filtering
32:58 in the blood, I still want hold things back, but I'm gonna
33:02 a couple more things to be able escape, right? Because I'm trying
33:06 get things out of the body. that's why you have these types of
33:10 , these fest traded. All So similar, but more pores and
33:14 type junctions. Then in some places the pancreas, we have these things
33:19 sinusoids, sinusoids. Here, the cells look like Swiss cheese. I
33:25 , and this cartoon is not an . All right, many things can
33:30 out of this. You have no membrane, you don't have really tight
33:34 and in fact, you can have gaps between cells. And so that
33:38 you're not holding anything back. Red cells can escape. White blood cells
33:42 escape large proteins can escape. And these structures, what you're trying to
33:47 is you're trying to allow the material escape. So like in the
33:51 what you're doing is you're sorting through cells and the uh the material that's
33:56 carried in the plasma to determine what and what goes. So these are
34:02 leaky, but these are the most . So when you think about a
34:07 , this is probably what you should thinking about. But when we get
34:12 some other tissues, you might see like those too. This is the
34:17 I was excited. Yes. Go , right. All right. So
34:25 question is, is why is this more leaky than that one? Uh
34:34 , so the level of regulation, the question is about regulation. All
34:37 . So the level of regulation is at the uh through the size of
34:43 molecules that are passing through the So again, we're just gonna keep
34:47 stupid. All right. So I'm give stupid examples. All right.
34:51 if I had really thin doors, can pass through the doors, think
34:58 this. If I had a thin , who could pass through the
35:02 could thin people? All right. ok. We can be a fence
35:06 . Could very heavy people pass through doors? No. So they're stuck
35:11 the building, right? So that be what's going on here. We
35:13 imagine here, I have thin doors only very small things can pass through
35:18 here. My doors are bigger. have more holes. So that's what
35:22 instead of doors, there's just more . So, if I have more
35:26 , more things can leak out. , nothing controls that. It's
35:34 it's a blood vessel that's basically coming a termination. Uh All right.
35:39 not, not entirely like I just . All right. So I'm
35:42 I'm gonna try to describe this a bit better. The purpose of the
35:45 and the purpose of the liver is detoxify the blood. All right.
35:50 we're making a great leap about to about things we're probably not ever going
35:53 talk about. All right. One the things that the spleen is responsible
35:56 , it's part of the immune system it is a surveillance organism or organ
36:01 its job is to go through and for pathogenic material. It's looking for
36:06 . So, in other words, debris, red blood cell debris,
36:09 red blood cells, all sorts of . And so when the blood vessel
36:14 in, it starts off as an and it breaks down to an
36:16 down to the capillary and then it in these areas that are called pulps
36:21 there's a white pulp and a red and we're not gonna go into
36:23 but basically what it is, it's , it's a, a structure on
36:27 many cells, many immune cells are located. So the blood just kind
36:31 empties out into this sinus area that this pulp. And what it does
36:35 it allows the blood to kind of through very slowly. And you're basically
36:40 it and filtering out the stuff that don't want, blood can't leave a
36:44 vessel unless it basically falls apart. that's what you're seeing there. So
36:49 capillary falls apart. Um, notice the big, super big
36:54 All right. So it becomes a , entering, entering into a specific
37:00 . That is a sinus. Right. That's exactly right. They're
37:05 falling apart. They're just structurally. , it looks like someone just beat
37:10 with a stick. Right? I it looks like Swiss cheese and I
37:15 , if you go look at them a microscope, the same sort of
37:17 , you would see these sorts of . Any other questions about this while
37:22 stopped? All right. This is fun picture. I love this
37:27 Not so much. I'm gonna ask a question specifically about the graph.
37:29 just, what's really cool about this that it's showing you the velocity of
37:33 blood versus the cross sectional area. right. That's why this is interesting
37:38 it shows you again moving from the back to the heart. So you
37:41 see where am I going and it's actually using all circulation here.
37:46 capillaries themselves are the site of material . All right. So what we're
37:50 is we're gonna be dealing with the of diffusion and we're gonna look at
37:53 process in greater detail here. All , they're very, very short distances
37:59 uh the blood and the surrounding So I think I mentioned to you
38:03 that there is no cell in your that is more than 10 microns away
38:07 a capillary. So all your cells receiving their nutrients and the materials and
38:12 able to deliver their waste because they're capillaries. So they are thousands and
38:19 and thousands of feet here saying centimeters terms of cross sectional area, you're
38:25 filled with the structures. All you have very, very thin
38:29 We've seen the endothelium already. They're narrow. We talked about the blood
38:33 , the red blood cells having to through a single file, they have
38:37 of branching which that cartoon kind of . And if you're imagining 10
38:43 you can imagine a centimeter by centimeter tissue would have miles of capillaries within
38:50 . All right. And I mentioned , I like, look if you're
38:53 to, if you're going into um going into uh medical in terms
38:59 health and you're dealing with heart Remember how do you get people to
39:03 blood pressure lose weight because you lose tissue, you're losing miles and miles
39:08 capillaries. That's the goal here. right. Now, why I like
39:13 graph? We have an increased surface . So look at the uh the
39:18 cross section of say the aorta very small, right? I
39:24 your aorta is about this big, ? That's not a big structure.
39:29 right. Look at the cross sectional of the capillaries, 3000 centimeters
39:42 All right. Can you pick That's 30 m, right? That's
39:51 . That's huge. All right. picture a volume of blood flowing through
39:56 aorta how fast it moves now, that out, same volume of
40:03 What's gonna happen to the speed of blood as it's traveling through the
40:09 What do you think? Speed slow down, stay the same.
40:12 gonna slow down, right? Because what it has to do is it
40:15 spread out and fill out that whole . All right. Now this is
40:21 you can think about traffic, There is a velocity of flow and
40:27 there is a flow rate. The of flow is the speed at which
40:31 go. If you went out there Houston at any time during the day
40:37 started putting speed guns on cars, do you, what are you
40:43 How fast are you going? What the speed of traffic? And in
40:47 that speed would be roughly average 80 an hour. I like that.
40:52 , woman, after my own get them going. All right.
40:56 , could you have if you had cars on the highway going 80 miles
40:59 hour, right? And you go say rush hour and you have 1000
41:05 going 80 miles an hour. All , what we're doing now is we're
41:09 with something different, right? It's amount of flow, it's how much
41:14 or, or in this case, many cars are moving, right?
41:18 so what this is uh demonstrating to is that when blood leaves the
41:22 we're only pushing out 70 mils, ? You remember how we kind of
41:26 that math, figure out stroke volume 70 mils is pushing everything forward and
41:32 going out really, really fast. as you start branching, those 70
41:36 are now being divided among many, vessels. And so those 70
41:42 you divide by the number of vessels you see there. And so the
41:46 the speed at which they go slows . All right. So what big
41:51 , it slows down? Who you an observation? Why does the body
41:55 the blood to slow down perfusion? being able to have exchange? All
42:02 . Um If you and I are by each other really, really quickly
42:05 I pass you something, what's the of you actually holding on to it
42:08 , to the thing if we're going , very. But if we walk
42:11 each other stop and I hand you , would you be able to grab
42:14 easily? Yeah. And so that's of what's going on here is that
42:18 slow the blood down in the capillaries that the exchange can take place,
42:24 ? That kind of makes sense. right. So we have lots and
42:29 of capillaries, the blood slows down , exchange takes place. And then
42:34 we do is we take these hundreds thousands of capillaries and we converge them
42:39 . And so you get capillaries to , venues, to veins and so
42:42 the blood returning back to the heart going to speed up. All
42:48 And that's what this is trying to you is the velocity down here starts
42:53 fast, slows down. And then you come back towards the heart,
42:58 speed up again, right? So and veins, we have blood moving
43:07 capillaries. We have blood moving slow terms of artery and veins. We
43:13 very little surface area. They are , they are highways, they are
43:19 59 and 2 88 and 45 and versus your capillaries, which are every
43:27 that we all live in, Traffic in the neighborhoods. Even if
43:33 ignore the speed limits, are they be fast or slow? Slow?
43:39 right. Now, blood flow through capillary is going to be dependent upon
43:47 degree of resistance. So this hopefully go back to that meta arterial thoroughfare
43:51 . All right. So blood flows an arterial. If it comes across
43:57 , arterial, it will pass And if the capillaries are open,
44:03 they will flow into those capillary beds then it'll move on and pass through
44:08 empty out into the venue and It'll go back up towards the heart
44:12 rest at any given moment of your . Only about 10% of your capillaries
44:17 open. It's kind of cool. , what your body is doing is
44:22 to determine where to send the blood the cells are telling them where to
44:26 the blood. The idea here is the cells know when they need glucose
44:31 they need oxygen. So what they is they send out a local signal
44:36 say, um we need blood capillaries then the capillaries cause precapillary, sphincters
44:40 open up and blood flows in. , you can think about this and
44:44 know this is a stupid example. my hand being a capillary bed,
44:49 ? And so here's a capillary, a capillary, here's a capillary,
44:51 on and so forth. They each an area in which I am sending
44:57 . So at any given time, of these are gonna be closed,
45:00 gonna be open. And so you imagine, I'm sending blood into this
45:03 bed. I'm providing all the nutrients all the cells that surround that capillary
45:07 they get all washed in all the and glucose they could possibly ever
45:11 But these guys are starving over here they go, hey, we need
45:14 . So what happens is is this opens up, these are no longer
45:18 a signal to keep the capillary, sphincter open. So it closes,
45:24 one opens up, blood gets sent . Oh, I've got all the
45:27 that I need. All right, that one up, open up the
45:30 one and I just start circulating the around in those different areas. Kind
45:36 cool. Huh. Yeah. And , and when do you not individual
45:41 , individual capillaries? Yeah. So individual capillary bed. So this
45:45 be an example of a capillary right? So that's the idea.
45:49 the thing that is driving this is metabolic need. It's the cells themselves
45:55 are making the signal that are saying need stuff. Now, I used
46:05 do an example here and I'll do . We're going to deal with these
46:08 factors, sympathetic activity and stuff. do that in a second. All
46:12 , the precapillary sphincters relax in response metabolic need determined by the cells surrounding
46:19 capillary. That's where the signal is from. When we get to
46:23 These are just simply the capillaries joining forming small veins. All right,
46:28 come come together, they have very tone veins themselves. Vinales also very
46:35 resistance, all right. But what do is because they're on opposite sides
46:42 a capillary bed. So the arterial the venue communicate. So basically arterial
46:47 saying, hey, I'm letting things through. So the vinue says,
46:50 , I'll relax and allow blood to my way. And so if
46:52 if I relax a venue, I'm dropping the pressure in there that increases
46:57 pressure gradient. So blood is gonna down that pressure gradient. That's the
47:01 here. All right. And then they converge and they form veins and
47:05 different sides, veins, right? small ones and large ones. This
47:09 just again showing you some relative volumes , very little resistance to flow.
47:15 what's happening here is that when blood into a vein, that vein instead
47:23 going, oh, I'm going to the pre the outward pressure, the
47:28 itself goes, uh I'll relax. I'll relax. And so what ends
47:34 happening is that the blood now has volume to fill up. And so
47:39 of rushing back to the heart, slows down, still moving towards the
47:44 , right? But instead of being towards the heart, like we did
47:49 the artery with I have an artery I'm squeezing it, I'm pushing fluid
47:53 it quickly. Instead the vein is , ah, so the blood slows
47:59 . It becomes a blood reservoir. kind of make sense. Now,
48:07 you are sitting down in your relaxed, slowly falling asleep to the
48:12 of my voice, right. Your is primarily sitting through those reconditioning organs
48:22 they're existing mostly on that Venus side your body. And again, Venus
48:27 means just the offside of the right? It's not just your left
48:30 your right side right now. When stand up, are your muscles gonna
48:36 a greater demand for oxygen and glucose they are right now while you're sitting
48:40 ? Right? And so what's gonna is is that through that simple movement
48:45 standing up? You, you guys familiar with orthostatic shock where you kind
48:49 get lightheaded and stuff. But that's basically, I don't have enough
48:52 pressure to drive blood back to my . And so my brain goes uh
48:55 so your bo body has to respond . But one of the things that
48:58 gonna do is it's gonna squeeze your . And so if I squeeze the
49:04 , what happens to Venus return? it go up or go down or
49:08 the same? If I squeeze my , blood go up, blood pressure
49:14 up? So does the blood flow up? In other words, back
49:16 the heart quicker? Does it slow or does it stay the same?
49:21 do you think if I squeeze a it increases? Have we already talked
49:27 Venus return? We have right. notice here when I squeeze a blood
49:38 , I increase the rate at which blood flows through it. So while
49:43 blood reservoir are your veins, what can do is I can increase the
49:47 at which it returns back to the and then my heart knows how to
49:51 with it because of which law Frank . Thank you. Good.
49:58 Yeah. Don't you wish you had kind of clues on the test?
50:01 the word? Yeah, I All right. So blood will
50:07 always, always, it never stops when it stops cir circulating you.
50:11 in trouble. Ok. Um, it's gonna be spending more time in
50:16 vein when the, when you're when the blood vessel, when the
50:20 itself is in a state of something for some of you all to
50:27 forward to nothing like berry coast Uh That's why I put them up
50:33 . All right, I mentioned to but we didn't talk about it.
50:36 remember we talk about that column of that the skeletal muscle pump interrupts.
50:42 you remember who was talking about It was way like on the first
50:46 of this unit, we said we the respiratory pump, we had the
50:51 muscle pump, we have the regular of the heart and then we also
50:55 the suction pump of the heart. , see a suction pump there.
50:59 was the clue. All right. we have different mechanisms to help drive
51:03 back towards the heart. And one the things that we have to overcome
51:07 the gravitational pull of the earth, is desperately trying to pull all our
51:11 down into our feet and away from brains, right? So how do
51:16 , how do we accomplish that? gravity is gonna pull liquid towards
51:22 towards the earth. And so to that, because we have so little
51:26 on that Venus side veins have valves these valves are pretty close together.
51:34 mean, I, I guess this all relative 2 to 4 centimeters
51:37 that feels like close to me. mean, that's probably closer.
51:40 you know, and so what this is that it takes that column that
51:45 skeletal muscle pump, we're saying we this to help interrupt this flow.
51:49 those, those little valves actually create and hundreds and hundreds of little tiny
51:57 . So the blood in one section 2 to 4 centimeters only has to
52:06 blood above it, which is a column of blood. And then when
52:12 blood goes in there, it only to push up a column that's above
52:15 and so on and so forth. it makes it easy for the blood
52:18 return back to the heart because you're pushing 100 centimeters of blood, which
52:22 a lot of blood that makes You're looking at me like no,
52:27 didn't make sense at all. ma'am. See, that's a,
52:33 a good answer. Explain it one time. All right, ever been
52:40 the swimming pool? Have we got to the bottom of the swimming
52:45 Like like the deep end, not shallow and shallow and is easy,
52:48 end. I know. That's kind scary. Some of you are
52:50 I don't like swimming. All Go down to the bottom,
52:54 the deep end of the pool you'll the pressure of the fluid on top
52:57 you. All right. Now, . Right. That you're in a
53:02 , very deep pool, like, , I don't know. Say 100
53:05 deep, you think the pressure in 100 ft deep pool is gonna be
53:09 than a pressure in the pool? only 8 ft deep. Is that
53:12 ft deep gonna be greater pressure than in 4 ft deep water, which
53:16 greater than 2 ft of water. right. Now, imagine being at
53:20 bottom of that 100 ft pool and have to now lift the column of
53:24 above you. Right. It's gonna a lot of work, isn't
53:29 Because you're lifting the weight of the of that water? All right.
53:33 you can imagine if I had to all that up, that would be
53:35 lot of work. And there's a of gravity pushing down on me trying
53:39 crush me. All right, so are you with me? Ok.
53:44 that's going on inside a blood So you can imagine at the bottom
53:46 your foot, that blood trying to back to the heart has to overcome
53:50 the blood in front of it, is trying very hard to go back
53:53 opposite direction. All right. So way that I can overcome all that
53:59 is reduce the pressures. So instead pushing 100 ft, why not instead
54:06 a little bit, right? So of if I can interrupt the column
54:11 valves, right? And you you got to think in terms of
54:13 column, don't think of a big pool, just think of a column
54:16 I can just interrupt it in the bits and all I gotta do is
54:18 lift the column that I have right me. Sorry, my wife says
54:23 , she's scared to death for me I talk cause hands right. All
54:27 gotta do is just push that little up and then if I can push
54:31 up, that's all I have to with. And then the column that's
54:33 me only has to deal with the on top of it. And the
54:36 on top of that one has to deal with the one in front of
54:39 . And so that's how the valve works, how it overcomes the gravity
54:44 you're no longer trying to overcome hundreds centimeters of blood. You're only trying
54:49 overcome 2 to 4 centimeters of That's lighter, isn't it? How
54:56 I move an elephant? Same How do I eat an elephant?
54:58 do I move an elephant just a bit at a time? Kill the
55:03 chopping it. A little tiny You have no problem moving it.
55:06 right. How do you eat an ? You've never heard this statement?
55:12 do I eat an elephant one bite a time? All right, you
55:17 shove the whole elephant in your They don't work. That's the same
55:21 going on here. I'm moving all blood, but I'm doing small bits
55:25 a time. I'm only responsible for part that's above me and that's what
55:29 valves do. It allows me to blood in an easy way. It's
55:36 the effect of gravity and is preventing backward flow because the valves open only
55:40 one direction, they open up so can move blood towards the heart when
55:44 pressure becomes too great, it closes valve and now I'm, I don't
55:48 that back pressure. The only back I have to overcome is just the
55:53 that's right above me. You guys about varicose fans, right?
56:03 Well, it does in terms of direct, uh it's a direct
56:08 right? I mean, you can't the whole column to move simultaneously,
56:11 think of it more like a domino , you know, I'm here,
56:14 I wanna go here. So I you. And so this one now
56:17 like, it's, it's now greater . So that causes the next one
56:21 move and so on and so So it's more of a like da
56:24 da da, da, da, , da, da, da.
56:26 a portion goes back and how much gonna be the same amount that left
56:30 heart, right? But what you're doing is you're not doing a smooth
56:34 is the idea, but you're not really see that it's so fast if
56:40 ever get an opportunity. Um, you're ever doing ultrasound, asked to
56:44 like ultrasound of bl blood vessels, fast blood moves through them. And
56:50 tell you like, you know, a muscle and it's like you get
56:52 watch it just, it's crazy. . Varicose veins. If you don't
56:59 what a varicose vein is, this just me telling you a pathology,
57:02 is a failed valve. And so happens is that the pressure on the
57:06 of the valve becomes so great that valve itself actually just kind of falls
57:10 . So now you're not just dealing that small column. Now you're dealing
57:14 the column and the column below you know, or above it.
57:17 then that one fails and the next does. And so the blood vessel
57:20 it's a vein will naturally just kind . And because the valves are all
57:25 , the blood vessel stays that size actually maintains that uh shape. And
57:30 why you end up with these V , right? That's what you're seeing
57:34 these pictures. So, and these the worst ones if you go do
57:37 Google search of, of varicose Uh It's just horrible. So this
57:44 basically a function of a high blood sustained for long periods of time on
57:48 venous side. That's really what that . All right. These typically occur
57:54 the superficial veins rather than the deep . Why not the deep veins?
57:59 they're deep to the skeletal muscle and muscle pumps constantly squeezes and breaks up
58:05 the column. Yes, ma'am, do. So, uh, so
58:16 of the ways you go ahead and , treat varicose veins is use compression
58:21 . What is a compression sock? a sock that has more elastic in
58:25 than your normal sock. And all does is just squeezes your leg.
58:28 so it's providing the pressure to drive blood, right. And so you
58:34 to overcome the pressure. And so , it's just constantly forcing the blood
58:38 . Yeah. All right. You , you can experience this yourself,
58:42 the varicose of aid, but if go a whole day without wearing
58:46 notice how your feet swell, And then if you wear socks,
58:50 notice that at the end of the , it's like, oh,
58:52 there's my, my, I might a little divot from where the edema
58:57 of collected above the sock, It's just your gravity is just desperately
59:02 to pull all the water in your down towards your feet all the time
59:05 you're young, you have healthy blood . So it's less of a
59:09 When you get older, you'll start people walk around and you're like,
59:11 can you walk like that? I , your foot looks, it look
59:14 a balloon. I remember seeing someone the, on the, uh,
59:19 the street car. What do we him here? Rail, the
59:22 And I was just like, I , he was going to the medical
59:24 and it was just like, I'm that his foot had split open.
59:27 know, it's just all the but it's just water is getting pulled
59:34 and you're having to overcome that All right, capillary exchange. So
59:42 you're a protein, uh you have be moved through the endothelium. All
59:47 . So it's gonna be through a of transit tosis. This would be
59:50 transport. If you're lipid soluble, gonna stop you. Now, you
59:56 move through the cell. That'd be cellular gasses again, trans cellular.
60:01 you're itsy bitsy, teeny, tiny molecule like a glucose molecule,
60:05 can pass in between the cells. right. So that would be
60:12 Um What else do I have up ? Everything is gonna follow fixed
60:16 Um And there are pores in the . So you can see the pores
60:20 formed here in a fin you just more pores, they're being formed by
60:25 um basically two vesicles. Um And just allows for the flow of material
60:30 them. So depending on where you , you're gonna see more or less
60:33 these things. And the idea is you're really, really small, you
60:35 pass through. And that's what klar is gonna involve is really these smaller
60:41 . If you're big odds are, , unless you're needed, you're not
60:44 be escaping. And I mentioned this because this becomes kind of important.
60:51 kind of forget this is when blood delivering or when vessels are delivering
60:56 they're not delivering it to the they're delivering it to the interstitial space
61:00 the cells, right? So it's exchange between the plasma and the interstitial
61:07 . And then there's gonna be an between the interstitial fluid and the intracellular
61:12 . So there's kind of a double there, right? So if I'm
61:16 glucose molecule, I'm not being handed to the cell directly, I'm being
61:21 between the plasma to the, the fluid and from the interstitial fluid into
61:27 cell. And then if I'm was , oh I don't know what's what's
61:31 waste. I'll, I'll just say dioxide, I have to pass out
61:34 same way I go from inside the into the interstitial space, interstitial space
61:39 the plasma. So all the rules diffusion are gonna be followed here that
61:43 learned uh previously. All right, things are gonna be passive that would
61:49 diffusion. So you're just gonna be the rules that we've learned about plasma
61:52 . So again, nothing new We're just gonna start applying the rules
61:56 we've learned in this particular situation. gonna be active things that would be
62:01 vesicular transport or carriers if they're All right, capillary walls are
62:08 You can see there, they're trying demonstrate the permeability. And so what
62:12 doing is if I can sneak then great, I'm just gonna follow
62:15 rules of diffusion in both directions. are two different types of exchange that
62:20 need to consider. The first type going to be individual molecules. So
62:23 you do is you're dealing with down concentration gradients, that's what you're
62:28 to accomplish. And so this is this picture is trying to show
62:31 It's like I have more glucose outside cell and plasma than I have inside
62:35 cell. So glucose is gonna want go inside the cell, right?
62:40 , I'm burning through oxygen. So am I gonna do? I'm gonna
62:42 more plasma. So this when we're oxygen, the net diffusion is going
62:47 be from the plasma into the carbon dioxide, net diffusions inside the
62:51 relative to the plasma. So we see that, but that's when we're
62:57 at individual things. When we're talking the blood, we're talking about all
63:01 stuff in the blood, we're talking all the stuff in the interstitial
63:05 So this is bulk exchange, it's to visualize it when we talk about
63:10 . And we brought this up Remember I said when I breathe
63:13 what am I breathing in air? ? And if I'm breathing in
63:18 what does air consist of nitrogen, and then everything else, right?
63:29 in Houston water, other pollutants, all sorts of stuff, right?
63:34 then we asked the question, what oxygen do? What does carbon dioxide
63:38 ? So, even though I'm breathing carbon dioxide, the net exchange of
63:41 dioxide would be from cells to the in my lungs. So it'd be
63:46 that gradient, right? That's the . This is the part where I
63:53 losing everybody. There are four forces . All right, the four forces
64:01 hydrostatic pressures and osmotic pressures. All . So before I explain anything,
64:07 a hydrostatic pressure pressure of a And which direction are you moving when
64:15 dealing with hydrostatic pressure towards the liquid away from the liquid? Think of
64:21 vessel. I've got fluid in Which way does that fluid wanna go
64:30 ? So, hydrostatic pressure is drive from the fluid. The other one
64:34 osmotic pressure. What is an osmotic caused by presence of solute? So
64:39 does a osmotic pressure do drive uh or towards the fluid towards the
64:46 Great. We have two different We have a space inside the
64:50 We have a space in the interstitial All right, each of them have
64:55 own hydrostatic and osmotic. All when we're talking about a capillary,
65:00 capillary sits between an arterial and a or a venue. And so the
65:07 because we have the flow through the , the pressures on the vinal side
65:11 be lower than the pressures on the side. Does that make sense?
65:16 . All right. So the sum those pressures or that pressure is a
65:21 of all of those four pressures that just kind of alluded to the hydrostatic
65:27 and the osmotic pressures in the plasma in the interstitial space. And we
65:33 them special names and they're very long names. And you can see them
65:36 here, we have capillary blood capillary blood pressure is the hydrostatic pressure
65:42 the plasma. So that's a pressure drives fluid in which direction towards the
65:47 or away from the plasma away says the name it's blood capillary pressure.
65:53 right. So that's an outward Second type of pressure we have is
65:58 plasma colloid osmotic pressure. So it to the plasma. It's an osmotic
66:07 . So, is it driving blood fluid or materials away from the plasma
66:11 towards the plasma towards good? All , then we have the interstitial fluid
66:21 . All right, there is a pressure. So in the interstitial
66:26 I have fluid is that pressure driving away from the interstitial space space or
66:33 away good. And then if I the interstitial space and I have colloid
66:39 , we really don't. But let's that I do. All right.
66:42 I have an osmotic pressure inside the space. Is that osmotic pressure driving
66:48 to the interstitial space or away from ? All right. So even though
66:55 names are big, they tell you what you need to know. Where
66:58 I going in which direction? That's, that's the idea what things
67:03 I looking for. And so when look at the driving forces of
67:08 we need to consider all four of . The process of filtration is the
67:13 the pressure that is moving materials out the capillary into the interstitial space.
67:22 process of absorption is moving materials from interstitial space into the capillary. All
67:30 . So when you're going through a , remember from the arterial side to
67:35 vinal side, I'm first going to and then I am going to
67:41 Does that make sense? All So all four pressures need to be
67:48 in both cases? All right. what is filtration? Uh filtration is
67:54 a greater pressure uh on the inside I'm moving out? OK. Does
68:00 kind of make sense? So what the pressures that drive materials from inside
68:06 plasma outward? All right. we said the plasma uh uh the
68:12 capillary pressure is an outward pressure. that's one we said that the uh
68:20 fluid has an osmotic pressure. no, sorry, hydrostatic pressure.
68:25 that's another one that drives well, trying to go out. So I'm
68:28 her head nod and I'm like, , that sounds like a good
68:31 All right. So the other thing to drive or pull water out of
68:36 capillaries would be the osmotic pressure of interstitial fluid. Right? Water wants
68:40 go from there to where there's So we need to consider those,
68:45 two pressures as being pressures that move from the plasma to the interstitial
68:53 And then when it comes to it would be the opposite to
68:59 The colloid osmotic pressure pulls fluid back the capillaries and the hydrostatic pressure pulls
69:06 pushes fluid from the inters spatial space the capillaries. Now, these pressures
69:13 at all times in all places. you just have to sum up their
69:17 values to determine their effects. When greater pressure is outward, then you're
69:22 have outward flow. If the greater is in towards the interstitial fluid,
69:27 I should let me make my terms . If I, if my pressure
69:31 outward away from the capillaries, then should expect those pressures that are moving
69:37 out will be greater than those pressures things in. But if things are
69:40 back into the capillaries, the pressure the capillary should be greater than the
69:44 pushing things out and that's what these are trying to show you the whole
69:49 , net positive and net uh negative stuff like that. That's all it's
69:54 . It's easier to see it this . Maybe not darn it. I
70:00 I'd change the slide. I thought had values on them and I don't
70:05 me see if I have, do have values over here? I do
70:07 . OK, I do. All . So gotta go to the Mary
70:25 bag. It's in there, I . All right, I am gonna
70:30 to this one. This is a easier to see. All right.
70:38 , that's what I want. I to go back one. All
70:41 So over here on the arterial I have a capillary pressure that's inside
70:47 capillary. That's pretty high. All . Um It is roughly uh 30
70:55 of mercury. OK. Hg The pressure out here in the interstitial space
71:05 like nothing. I don't have plasma in the interstitial space. Why don't
71:12 plasma proteins in the interstitial space? they are, let me see if
71:21 else can see it. I don't plasma proteins in the interstitial space because
71:24 are plasma proteins, right? So colloid osmotic pressure in the interstitial
71:33 I'm gonna just circle it. So capillary pressure here is about 30 the
71:40 fluid, uh colloid pressure is roughly zero. All right, this is
71:47 fun one right here. The Now, these are relative to atmospheric
71:53 . That's where these values are coming . The pressure inside the interstitial space
71:59 roughly equal to zero. Now, can prove this if you want to
72:05 just find a friend, get a , stick it in your friend.
72:11 have to agree to it first and watch and see if they squirt like
72:16 cartoon character. Do they squirt like cartoon character? I'm not talking going
72:21 a blood vessel. I'm just, into the, do they know?
72:26 the pressure inside your body is roughly same as the pressure outside your
72:30 So this is about zero. And on the capillary side, on that
72:38 , it's about 15 millimeters of Now, where do those numbers come
72:42 ? You can go and measure All right. So it's just the
72:45 number comes from, it's just the pressure, right? It's, if
72:48 measure it, you'll just see. as fluid is leaving out, as
72:53 blood flows out of the capillary fluid out of the capillary. What's happening
72:57 the pressure over time it's going right? So again, think about
73:05 vessel, if I take fluid out the pressure getting less and less and
73:09 inside the vessel. Yeah. And that's what's going over time. And
73:13 that's why we see the difference here there. All right. And then
73:20 we gotta do that was the said . Not ac that's a zero.
73:25 right. So on that side, have uh for the filtration, I
73:33 30 for absorption on that side, have about 15. OK. And
73:39 I take 30 minus 15 and what I get? 15? And you
73:43 see over there the pressure, the pressure is outward plus 15. That
73:47 be a positive pressure. So what's is I'm driving fluid out but as
73:52 drives out, what happens to this , what happens to this pressure?
73:57 fluid leaves the vessel? What is to happen? This is not a
74:01 question. We just said it's gonna smaller. So as I move in
74:05 direction, that pressure gets smaller, right, I'm gonna say it gets
74:12 really low to about 10 millimeters of . OK? And then we just
74:19 the same math 10 minus 15 would negative five. I mean,
74:28 I'm making up a number here because numbers aren't exactly these numbers. If
74:32 have negative five, that means the no longer is pushing outward, it's
74:37 inward. And so blood wants to which direction or fluid wants to go
74:42 direction into the capillaries. So what gonna see is something like this in
74:48 of flow. So think of this your capillary blood first flows out,
74:53 mixes and then because the pressure is on the inside, it goes back
74:59 . And so what you've done is now created a float outward to
75:06 You've taken glucose and oxygen other things you delivered them to the interstitial space
75:13 then what have you taken away? mixed them up and so what are
75:16 going to take away waste carbon dioxide you're producing all that stuff? Are
75:24 gonna take away oxygen? What do think if I'm mixing things up?
75:30 . Why not? Am I gonna away glucose? Sure. But am
75:35 gonna take away the same amount of that I delivered? No, if
75:40 breathing in, do I have carbon circulating in my blood? What do
75:43 think if I'm breathing? Yeah. am I delivering carbon dioxide to this
75:49 ? I am but I'm delivering a less carbon dioxide than I'm gonna be
75:55 away. So more carbon dioxide So I'm taking away those wastes carbon
76:02 being a waste. And the reason all happens is simply because of the
76:08 in those pressures. So I'm gonna back to slides and actually those are
76:14 numbers. So I was off by little bit by five millimeter mercury,
76:20 ? What you need to walk away is when we're dealing with capital air
76:23 , we need to consider all four these types of pressures and where they're
76:30 , they all have an effect. pressure pushing in and pressure pulling out
76:36 you have to consider all four of at the same time. Two of
76:40 have no value because there is no osmotic. There is a colloid osmotic
76:46 pressure for the interstitial space. But there's no proteins, it's equal to
76:51 , but it still has an If you subtract $0 from your checking
76:55 . Did it have an effect? it something that you could measure?
77:02 this something you could measure? you better say yes because you guys
77:09 learned mathematically, there are things with thing with a value of zero that
77:15 still something right? You gotta remember . So it exists, it just
77:21 no value. Let's say we just you full of salt. We're going
77:27 to first unit stuff here. If pump you full of salt and put
77:30 whole bunch of interstitial uh put that into the interstitial space. Are you
77:34 to have a colloid osmotic pressure that's to draw water into that space?
77:38 , you are. But right now don't, it's equal to zero.
77:43 right. So you have to consider , it exists. So when you
77:48 the math, if you do the , when you're considering the net exchange
77:54 why blood moves out and then moves , it's because all four of these
77:59 had an effect on that flow. right. Does that kind of make
78:04 ? Or have I lost every single of you? You need to,
78:11 need to chew on it for a bit. So it's kind of like
78:14 jerky. I don't think there's such thing as tofu jerky. So,
78:19 you're a vegetarian, I'm sorry, heard her opinion. What about
78:31 You're ok. You want to chew it? Ok. You can ask
78:35 about it. All right. I I've got two minutes and I got
78:39 down on this. Usually I can through that one. All right.
78:42 let me tell you why this is , not just because of capillary
78:45 but when we get into the kidney the next unit, the first thing
78:48 gonna do is we're gonna deal with three pressures and pressure gradients and how
78:51 drive fluid through the kidney. So is one of those things that it's
78:55 like, oh I hope it's not be on the exam, it will
78:57 on the exam and then it shows again. OK. That's, that's
79:01 we kind of deal with it. the good news. Pressure gradients are
79:04 gradients high versus low. That's all gotta do. And you just gotta
79:08 what is causing the pressure? Is fluid or is it solute? And
79:13 is that pressure located? Is it the capillary or is it outside the
79:18 ? That's the easy thing. I'm do this one slide. And then
79:22 out of here. Just remember when dealing with the extracellular fluid, the
79:26 fluid has three consecutive loops or conductive first loop we already learned about.
79:32 . This is the simple one that's output. That's five liters per minute
79:36 roughly 1700 liters per day. Your works like a, a workhorse 1700
79:44 per day. All right, you know what a 55 gallon barrel drum
79:50 like. That's like the oil, barrels. That's 55 gallons multiply that
79:55 , that's 100 and 50 liters. , can you now start picturing volume
80:01 ? A lot of those? All . Second one is what we just
80:06 . That's the trans vascular loop that's in and out of the capillaries.
80:10 are we doing? We're doing roughly liters moving in and roughly 16 to
80:18 liters moving back or moving into the space and then moving back into the
80:24 . So that's what the reabsorbed Now, if I'm doing my math
80:28 , 20 minus 18 is two. out of 7200 liters that are circulating
80:38 20 liters are moving out of the and moving back in to the capillaries
80:42 I'm leaving two liters behind. And many liters do I have in my
80:50 ? Five, if I take two of fluid out of my blood,
80:56 have three liters left. And since that fluid I'm moving is liquid,
81:01 my blood turning into sludge? That's good. So you mean over the
81:11 of the day? My blood is a sludge? No No,
81:13 you'd be dead. So we have third loop. This is your lymphatic
81:17 . This is what we're gonna come to. It's going to figure out
81:20 it's not gonna figure out it's going take those two liters that you just
81:23 . And it's gonna say no, , no, this is not where
81:25 belongs. You don't have edema. is not what our goal is.
81:29 need to get you back to the . And so when we look at
81:32 lymphatic system, we're gonna see how does. That, man. I
81:35 running out of time. I'm gonna to start sprinting through the respiratory
81:40 I get too excited to talk about stuff. All right. So enjoy
81:44 weekend. What do we do this ? We go to the UU football
81:52 because this is the last time we play them in our history. We're
81:58 Saturday, wear your red, come class, not as a horse,
82:06 I guess we get two weeks, think
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