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BIOL 3324 Human Physiology - BIOL3324_lecture14_1003
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00:19 So maybe you'll be fortunate. My will give in the next hour and
00:23 I'll just be like, OK, done. Um What we're doing today
00:27 we're gonna continue on with understanding the cycle. So we've been talking about
00:32 heart. We've been talking about how goes about producing this pumping action.
00:37 stopped with the conduction process. And that's kind of where we're gonna be
00:42 is really, really simple and We're gonna be moving through those different
00:45 . We're gonna go from the S node to the A V node,
00:48 the A V node to the bundle his bundle of his to Perini
00:51 So you just kind of, I I talked really fast there. You
00:54 have never had the opportunity of having actually speak at my normal pace.
00:59 right, I'm like an auctioneer. right. So what we're gonna do
01:03 we're gonna walk through this and then gonna transition and we're gonna start talking
01:06 little bit about the effects of the nervous system on those uh different types
01:11 action potentials which causes your heart rate go up and slow down. We're
01:14 see why that happens and then we're move over and deal with the cardiac
01:19 and we're gonna look at a graph is gonna make you all go.
01:22 , but then after I explain you're gonna like, ah, this
01:25 really cool and very helpful, even you don't just pretend and just uh
01:30 right. So here we are, going to talk with about the conduction
01:33 the action potential through. Now, literally talking right now about a single
01:38 potential. But when we're going to talking about the cardiac cycle, we're
01:40 to talk about the sum of all action potentials. All right, and
01:44 going to talk about how they relate the ECG as well. So remember
01:49 is just a single thing so we kind of see the path of conduction
01:53 . So the action potential job is start up here in the essay
01:58 And what it's gonna do is it's move between both atria. Now,
02:02 reason we want them to go to both Atria is because we want both
02:04 left and the right pump to pump the same time. Does this make
02:08 to you? If I have a that is a figure eight, if
02:11 pump both at the same time, gonna move fluid in both things at
02:15 same time. So that blood is to both chambers at the same time
02:21 you were kids, did you ever ring around the Rosie? If someone
02:24 moving and ring around the Rosie, happens to the ring? It breaks
02:28 or collapses. Right. So, the same sort of thing. If
02:31 one side pumped, then what you're is you're putting pressure on that other
02:35 and basically you'd cause lots of Right. So we want both the
02:39 to contract and we want the both to contract at the same time.
02:43 what we're going to see here is they're not exactly at the same
02:46 but they're close enough for, for for if you're going to be a
02:50 , it's not gonna work. So what we have here is we're
02:53 to move between the two atria, is called the interatrial pathway. And
02:57 the ax potential is basically moving along very specific track of, of these
03:03 auto rhythmic cells to then go to contractile cells in the atria. So
03:08 we can both, both sides, atrial will contract simultaneously at the same
03:15 . That signal is also moving from S A node to the A B
03:18 via the inert nodal pathway. the interno pathway is just simply saying
03:23 want the signal to be able to down to the ventricles here. So
03:27 going to use again contract or the RTH cells to send that signal and
03:31 we're going to see is that there going to be a short pause just
03:36 the signal arrives in the A V . And this is called the A
03:40 node will delay, right. So starts s A node spreads to the
03:45 both sides of the uh are both signal goes down to the A
03:52 the two Atria contract, the signal paused at the A V node and
03:57 from the A V node, what up happening after I press the button
04:00 make it all go down. Uh gonna happen is uh this is the
04:04 thing. So it's just the same . So it's just saying,
04:07 I'm paused there. And then what's happen is we're waiting before we start
04:12 the ventricles to depolarize really super just like Wiley Coyote. All
04:26 So what we wanna do is we make sure that the ventricles are ready
04:29 receive the blood before they start So this is why the AV node
04:35 exists. So as a node interatrial cause those muscles to contract. At
04:41 same time, we send the signal the AV node, we pause
04:44 we wait for the contraction of the . Then the signal from the AV
04:48 begins to travel down the bundle of . So it goes right down through
04:52 center septum through the cardi hits that and then what it's going to do
04:56 it's going to spread out and move those Perini fibers that are embedded through
05:00 walls of the ventricles. Now, muscles here are contractile muscle. All
05:06 . So what we're doing is we're sending a very quick ax potential from
05:10 to cell to cell via the auto cells. These are not neurons.
05:14 what we're doing is we're getting it out very, very quickly so that
05:18 that blood or when those ventricles they're going to be doing it
05:22 And so we have now then is have a pattern of contraction, we
05:27 the two contract and then they relax just as they begin to uh just
05:33 they begin to relax, we get ventricles to contract. So blood is
05:36 to be ejected, both in the system, blood is gonna be ejected
05:39 the systemic system. All right. because of the pattern in which we
05:44 produced, that makes sense. So in terms of the conduction, this
05:51 right here kind of puts it up a better way you can see
05:55 So you can see here, I'm and I'm down, then I get
05:59 depolarization. So what we're seeing is massive depolarization that's going straight down the
06:05 and then out along the arms and the, from through those pre kidney
06:09 up and around to all the contractile that makes up the rest of the
06:13 . Do you guys remember? Percentage how many of the athm cells makes
06:17 as a percentage of the muscle 1%. So everything you're looking at
06:23 there is mostly contractile, right? that's what's doing all the work,
06:29 auto rhythmic is doing. The You guys are awful quiet. I
06:42 I've been hearing too much talking so I'm, I want noise.
06:45 right. You can, you can ask questions, please. There is
06:50 such thing as stupid questions. Uh-huh. Oh So when you're talking
07:02 vasoconstriction, vasodilation or cardio constriction. when you are causing um uh
07:09 what you're doing is you are making vessel smaller. OK. So when
07:14 talking about a contraction in the what you're doing is you're taking a
07:19 and you're squeezing the chamber. So making the chamber smaller. And so
07:23 means the volume. Oh You're starting open up the whole can of worms
07:27 Boyle's Law here. No, that's not. Sorry. That's something
07:30 you guys have to know. Do guys remember Boyle's Law? Do you
07:34 remember Boyle's Law? P one V equals P two V two. You're
07:39 , oh my goodness. There's It's starting to show its ugly head
07:43 . Yeah. So what we're doing is we're reducing volume space and increasing
07:48 at the same time. So what gonna do is gonna force ejection.
07:52 why it's happening. We're going to this here shortly in much more
07:57 much greater detail. All right. , but the term when you hear
08:03 constriction or constriction, what you're doing you're making a smaller space, dilation
08:08 be wider. All right. So you guys recognize this pattern right
08:17 What this one is? This the line? Do you remember what that
08:23 from today's Thursday? Right? Do remember from Tuesday? So this is
08:28 action potential of which cell you Two choices, contractile or auto
08:37 She votes contractile. Who wants to ? Auto rhythmic? Yeah, I
08:46 asked you a question. That's not the slide. It's an auto rhythmic
08:49 . All right. These are the . They're the ones that are determining
08:53 heart rate. All right. So me just help you out here.
08:57 right. Is your heart beating at specific rate right now? OK.
09:01 next question determines your final grade for class. OK. Your heart rate
09:08 up a little bit. OK. . And that was the question.
09:15 right now. So your heart rate a natural pace, right? The
09:23 note. Remember we said it creates pace of the heart. So if
09:28 want to make my heart rate go , I've got to change the
09:31 If I want my heart rate to down, I have to change the
09:35 . We're going to do this through autonomic nervous system, right? So
09:39 I scare you, what's gonna Heart rate go up or down,
09:44 up right. When you sit on sofa and veg what happens to your
09:48 rate? It goes down. All . And so we can quickly,
09:52 taxis to the two different things we about the autonomic nervous system, sympathetic
09:56 parasympathetic. So, what's going on regard to the sympathetic, what we're
10:00 to do? You can see here's the normal pattern. All
10:05 And what we're doing is you can if I count up 123, what
10:08 I done in terms of the heart here? Just counting the number of
10:12 , right? 12345. So I'm the rate. So how do I
10:18 the rate? Well, what I to do is I want to spend
10:21 time in my hyper polarized state and want to quickly rise to get that
10:26 to happen. And so what I'm to do in order to make that
10:29 is I am going to increase sodium permeability. How do I increase permeability
10:37 in more channels? So that's what do is we introduce channels. And
10:42 when we introduce those channels, that's instead of have this slow rise,
10:45 happens is I have a fast rise so I quickly go up and then
10:49 order for me not to get way here, what I'm gonna do is
10:53 going to decrease cum permeability. So look at where the resting potential is
10:57 it's not truly a resting potential because , we don't really rest, we
11:01 hit that bottom and we start rising . But look at where it is
11:04 , it's on that minus 60 but where it is here. About minus
11:10 ish, maybe minus 50. So have I done? I'm still opening
11:16 potassium channels, but I'm opening So I don't go down as
11:20 I don't shoot or overshoot to get that low level of hyper polarization.
11:26 I spend less time in a hyper state and I spend more time
11:31 So it happens quicker. The other that happens is that this sympathetic activity
11:37 going to increase the contractile cells activity increasing the influx of calcium into the
11:43 . All right. So we're gonna a little personal here. Who should
11:49 pick on? Remember, I'm Right. This is the splash
11:58 So sorry, I'm picking on you . So this really, really cute
12:01 comes up to you and he holds hand and gives you a big old
12:05 peck on the cheek. Is your gonna start beating faster? You've had
12:10 crush on him for quite a OK. Right. Can you feel
12:15 heartbeat when it goes up? I mean, you get the whole
12:24 . Yes. Why? Because the are harder now because I'm letting more
12:30 into the contractile cells. Right. I'm not only speeding up the speed
12:35 acting on the algorithmic cells. I'm acting on the contractile cells to create
12:40 , stronger contractions. All right, guys don't want to talk about getting
12:44 . Fine. I can see that's problem here. You guys need to
12:47 out more but. Ok. Um are running, what are we running
12:53 or what are we running to? late for class. Sounds like a
12:57 thing when you're late for class and carrying your £50 bag with all those
13:02 and all of your snacks and your and your change of clothes and everything
13:06 you own because reasons and you're carrying that weight. Can you feel the
13:11 beating in your chest after 100 Boom, boom, boom,
13:19 It's hitting hard and fast again. what's going on here is I'm letting
13:23 calcium in. That's why I'm getting contractile cells. I'm speeding the whole
13:27 up. Sodium and calcium levels have potassium levels have decreased or permeability,
13:33 levels. All right. So that's characteristic, right? I show up
13:37 class. They canceled. I'm too to do anything. So I sit
13:41 the chair and my heart rate goes and I fall asleep. OK.
13:47 what is, what am I doing ? Well, I'm just doing the
13:50 . All right, I'm going to sodium calcium permeability and I'm going to
13:55 . Uh I said sodium calcium is I'm going to uh increase potassium
14:01 I just flip it around. And what ends up happening is my heart
14:04 up beating slower. So again, have 123 and how many peaks do
14:07 have? We have 12 parasympathetic peaks ? So what am I doing?
14:13 getting a slower depolarization. Why? , there's less permeability. So instead
14:17 moving faster towards threshold, I'm taking sweet time to get there. So
14:23 why it takes so long for me get that beat, but I still
14:27 it. And then what happens is I've increased potassium permeability. I drop
14:32 down. I hyperpolarize beyond my normal polarization state. That's what they're trying
14:37 show here. So remember here we , that's my normal low point,
14:42 ? My rest. Now, what I doing? Because I am have
14:47 permeability for potassium. I shoot far that. So not only do I
14:53 slow, I have to climb And so that's why it takes longer
14:58 me to get a heartbeat. Does make sense? So this is why
15:03 important to kind of look at these and ask the question, what is
15:06 on in each of these slopes? is sodium, that's calcium, this
15:10 Tassi. So if I affect what does it do to that
15:15 And that's what the graph is showing here. So that's how you should
15:19 it. I just kept it The heart. It's sympathetic sodium,
15:24 increases permeability. Uh potassium decrease flip when it comes to parasympathetic. So
15:34 . So good. Does that make ? Yeah. OK. In the
15:39 making sense? All right. You seen this before? The ECG from
15:50 machine that goes ping. Yeah, an old school reference. Let's see
15:56 anyone gets it. No one gets . What do I say? When
15:59 one gets anything you need to get , you need to get out
16:04 OK. What we're looking at here the ECG, this is the
16:08 I'm just going to tell you right . This is what the perfect textbook
16:11 of an electrocardiogram looks like when you doing electrocardiograms, you'll see them and
16:16 go like this looks like nothing in textbook. It's all there, but
16:20 takes a while to start interpreting how you put on the leads and
16:23 sorts of fun stuff. And then find out that people have all these
16:26 abnormalities that don't appear in the Like my, my close friend uh
16:31 heart. He, you know, , you know, he's very
16:34 he did his EK or ECG when joined the military and he had an
16:39 down um QR S complex. And was like, why? And it
16:44 actually just because of the way that heart muscle was arranged, it actually
16:48 the wave. So there's all sorts weird stuff that can happen to
16:51 but we're going to learn the perfect OK. Just because right now what
16:58 is, it's a recording of the currents right now. Notice a plural
17:03 , currents. All right. It's about an action potential. It's about
17:08 flow of current through the heart. what we're doing is we are focused
17:12 the heart which is centrally located and putting leads in different places around the
17:18 . All right. So this is the simple view where you can see
17:21 have our leads here located at the and the two arms. But uh
17:25 mean, this is more accurate. you can see here it's showing you
17:29 three. But they also, I I had a picture of this
17:32 it is um you also put them the surface of the chest. So
17:35 usually have a couple of leads And what they're doing is each of
17:39 leads are comparing uh point A to particular lead, which would be the
17:44 B. All right. So just this simple thing is like, I'm
17:48 at the heart from here and this looking at the heart from there.
17:51 I'm actually comparing the two views and view here versus that view there.
17:56 this view here versus that one there then you put the ones over the
17:59 . And so you have to do comparisons as well. And so this
18:02 why you end up with a composite that looks like this right. The
18:08 that I, I do this, you're familiar with, uh, watching
18:11 football is pro football has probably about or 50 cameras, uh, arranged
18:19 the field in different ways. College less so, but we still have
18:23 right there. There's more than just camera. And so if I watch
18:27 play and there's a questionable call, do they do? They call a
18:30 out and then they start doing the , different views because it's that different
18:35 provides a different perspective of that electrical that's occurring in the heart. And
18:40 fact, that's what um this actually both of them do is they're
18:45 you see how they're slightly different from other. It's because of that particular
18:50 . So this one is trying to you the left lead versus the right
18:53 versus this. This is what it give you. And then here's the
18:57 different comparison where, what this is you would see from that view.
19:01 is what you're seeing from that so on and so forth. And
19:05 , we're not trying to memorize what of them does. The idea here
19:08 that they give you a different view a different perspective of that electrical activity
19:12 the heart and the electrical activity. current is all those action potentials causing
19:19 . And so we're dealing with not the actual potential in that nerve
19:23 we're talking about the actual potentials through contractile cells which or through the the
19:28 cells or the auto cells, then through the contractile cells resulting in a
19:34 contraction. So that's what we're actually here is the the events that are
19:39 there. So this is not a recording of the electrical activity. This
19:43 an indirect, right? Because I'm over here looking at stuff, if
19:48 was a direct recording, where would put the, where would I put
19:50 lead on the actual heart muscle wouldn't I? Yeah, so this
19:56 an indirect and the other thing is it is not a single action
20:01 it is the sum of all the activity, right? So it's a
20:07 bigger picture than what we're uh than you might be kind of giving it
20:12 to or thinking about. All So it gives you an an assessment
20:16 how the, the heart's working. I, again, I'm not gonna
20:19 you how to position these things. just showed these so that you could
20:22 that there are very specific positionings to the uh beautiful picture that we're looking
20:28 . So what we end up with this particular form. All right.
20:31 so there, there's, they're showing 22 of them, but we're going
20:35 just focus on one or the You can pick which one you want
20:37 do what you're seeing here are three wave forms. The first wave form
20:42 called the P wave. All So you can see here it's a
20:45 small bump. And what this is to represent is the atrial depolarization.
20:50 right. So this is the electrical of all the depolarization that's taking place
20:55 that atrial muscle. All right. spreading over it just before the contraction
20:59 place. And then what we have we have the QQ Rs. So
21:03 can see it goes down and then goes up and it goes down.
21:06 this is the ventricular depolarization. And this represents is the pattern of
21:13 of the action potentials traveling down the of his and then back up and
21:19 and then across all of those tissues make up the ventricular walls, which
21:24 why you have that down, up again. All right. And then
21:29 , we have over here, the wave, the T wave represents ventricular
21:35 . So if depolarization signals the point the cells are contracting, what does
21:40 repolarization represent? Relaxing? OK. we got contraction relaxation based on
21:46 What do you see is missing atrial ? Why isn't it up there?
21:54 , it is, you just can't it. All right. So I've
21:58 you guys, I have four kids they're not as young as they used
22:01 be. So this analogy is gonna stupid now, but let's say this
22:04 10 years ago and I have, youngest twin looks a lot like
22:09 All right. Actually, my eldest also looks a lot like me.
22:11 just know out there there's gonna be of me. So you guys are
22:16 doomed. All right. But my and he, he is a true
22:21 . I mean, just shy as be or was shy as can
22:24 Now, he's just bold and Um But if I had brought him
22:28 the classroom and brought him up here the front, you know, he'd
22:31 all of you staring at him. the first thing he would do would
22:34 , he would jump right behind Right. And he would just hide
22:39 . And if I moved, he sit behind me the entire time and
22:43 where the rep polarization is. It's there and it's hiding and the place
22:47 it's hiding is here in the QR right now. It's not a very
22:53 wave. So let's look just briefly , look at the QR S.
22:57 this a big wave relative to the wave? I mean, is this
23:01 bigger than that one? Yes. . So you got a big wave
23:04 you have a small wave. And you can imagine for the Atria,
23:07 would have the same thing, we a P wave which would be the
23:10 wave. And so it's repolarization would a tiny wave. And so that
23:14 wave is just hidden behind the big wave, QR S OK. So
23:20 there, it's just now you can that there are these gaps. So
23:30 see there's a gap there, there's gap there, there's a long gap
23:33 and then, then Wrench repeat, ? So we have what is called
23:38 PR segment, the PR segment is period of time where you have an
23:41 V not delay. Oh So I depolarization and repolarization before the ventricles
23:48 Yes. And so it's represented up because there's no electrical activity, there's
23:53 delay that's taking place, right? what else do we have?
23:57 we have the uh ST segment, this represents is the plateau phase of
24:04 ventricular contractile cells. Now, I'm gonna draw this to remind you guys
24:11 I can ever find my things in little bag. My Mary Poppins bag
24:20 remember what does an action potential of contractile cell looks like it goes up
24:25 this. So when we say it's plateau phase, that's what we're
24:28 It looks like that's what it OK. And then we have the
24:33 ray uh interval, which is just the period of the heart at
24:36 So think about your heartbeat again. do we get? I'm gonna actually
24:40 a real sound instead of saying thump. Like I was, I'm
24:43 use the language that they use when describing the heart. It's Lub
24:46 So Lub dub, Lub, Lub dub. You see that big
24:53 . So that's what that long interval , that TP interval represents that long
25:00 . OK. So this ECG describes of what's going on in the
25:09 right? I have here. I've depolarization of the atria, right?
25:17 this is contractile. So I'm gonna to do this in such a way
25:21 I don't flip the slide. Oh should be doing a different color,
25:25 I um let's pick blue, maybe will stand out. So I'm gonna
25:33 contraction and I get rest, So we're gonna see contraction taking place
25:40 that space like so then this is to initiate the second contraction that would
25:45 ventricular contraction. So there's the action for that. And so you'd see
25:51 relaxation like, so that kind of sense. Now we're gonna put this
25:56 a larger diagram. So it'll make sense because I'm drawing on a little
26:00 itsy bitsy thing here. What we're look at here in about five minutes
26:03 what is called the Wiggers diagram. what it's gonna do is it's going
26:07 take all the electrical activity of the , all the activity of the
26:10 like what's going on with the what's going on with the ECG where
26:14 the volume of blood going and all other things and it's going to put
26:17 all together on one thing. But this is trying to show you what
26:21 trying to show you in this little here is that this ecg correlates with
26:27 events of the heart. So when get the h here contracting, it's
26:31 place here and when we're getting the contracting, it's taking place there.
26:39 makes sense in those segments. And the depolarization and the repolarization are represented
26:45 the humps, right? These little um uh what am I waves that
26:52 seeing that are being formed here? . Did I lose you all someplace
26:59 are you? OK. Got two , two thumbs up. Uh
27:04 There we go. Now we're starting get courage. Go ahead. Say
27:09 again. The QR S, it's the, it's just the, the
27:13 of all the electrical activity of the . So if I go back,
27:16 here, back another slide, oh got to go way back right
27:20 So basically, you can see what's my, what's my um uh
27:24 form doing? It's going down and back up. So that's what it's
27:28 representing is just you're seeing it kind do this up down thing because of
27:31 direction that the bundle hits the Perini go. So that's why it has
27:38 particular appearance of like that. And think I have a slide here in
27:43 little bit that actually shows you how muscle is formed. So um I'm
27:48 , I'm gonna jump ahead here. When the muscle contracts, what it
27:51 is it squeezes the, the, chambers kind of like you would squeeze
27:55 out of a towel like this or you'd like to milk a cow or
28:00 a goat, right? You don't pull down, you basically, you
28:05 like, so, so that's how milk. And it's kind of the
28:09 thing. If I had a towel of water, I'd squeeze like this
28:12 draw the water out. The muscle the heart is arranged in that spiral
28:18 so that it can do that. so it can direct the flow of
28:21 downward and then back up out through arteries which are on the base of
28:27 heart, which is very confusing because base is at the top and the
28:30 is at the bottom. I know confusing. So it's a language
28:37 No. Can we move on or you need to address this flow?
28:42 . Yes. Yeah. Go So like what point is it can
28:49 , we'll get there in like three . Excellent. Might be five
28:53 but we're getting there because it's so I said, the Wiggers diagram is
28:57 of the most valuable tools we'll learn you need to know about the
29:01 But we're afraid to ask can be in that diagram even though you'll look
29:03 it and go. Don't worry, not that scary. It just looks
29:07 the first time you see it. right. First off, we need
29:10 understand when we talk about the there is nothing opening and closing the
29:13 other than the pressure and the back , right. So a valve is
29:17 passive structure. So if it's in shut position, it will open when
29:22 pressure behind the valve causes to open then the fluid flows through and then
29:27 the pressure becomes greater on the front , it causes the valve to slam
29:31 again. This is purely passive. is not dependent upon some sort of
29:36 signal to say time to open and . All right, solely responding to
29:40 activity of the pressure or to the pressure gradients that are going to be
29:44 created through the flow of blood and contraction of the heart. Ok.
29:51 , not electrical passive, we're gonna the state to help us find uh
29:59 stages. So, we've already mentioned dias from Tuesday. Cyle means
30:04 Dias means relaxation. Typically, when talking about cysto and diastole, we're
30:10 about the ventricles and we're completely and ignoring the atria. All right.
30:15 if you hear someone talking about you can just presume it's ventricular
30:20 If you hear dias, you can uh ventricular diastole, but the atria
30:26 its own cycle of cyst and And so we usually precede it with
30:31 cysto atrial diastole. All right. so this is showing you a little
30:35 a chart here showing you the different . And so on the outside,
30:39 can see that would be ventricular on inside circle. There's just showing you
30:43 periods of time where you have atrial diastole. All right. So you're
30:48 want to have atrial cysto precede ventricular and you want the just intuitively
30:57 if I'm pumping blood out of the of the ventricles, do I want
31:00 ventricles to be in diastole or cysto they're receiving blood diastole? Right?
31:06 , a lot of this stuff is gonna be straightforward intuitive. You
31:09 I want to be relaxed so that can receive the blood, right?
31:13 when I'm pumping blood, I'm, , I'm actually creating that force to
31:17 the blood forward. Right. depending on which textbook you go
31:25 Unfortunately, ours is simple. They four stages, some textbooks like
31:30 I've seen some as many as All right. Four makes it
31:35 All right, we're going to have four phases and we're gonna just keep
31:39 like this. We have the inflow , right. That's the first phase
31:44 . What we're doing is we're just simply about the valves themselves. All
31:48 . So think about the ventricle on inflow side of the ventricle, we
31:53 a valve on the outflow side of ventricle, we have a valve,
31:56 ? So if I'm inf flowing into ventricle. That means my inflow valve
32:00 to be open and I don't want blood to be blood flowing backwards into
32:05 ventricle. So that outflow valve is to be closed, that help the
32:14 phase is referred to. And we're , I should show you this is
32:19 we're starting. So here we can there's our inflow phase. So you
32:23 see my valve is open circle it then right here my valve is
32:30 All right, if you do it the uh left side of the
32:32 same thing is gonna be there, ? I'm open and you can't see
32:36 other valve because it's kind of jammed in there like there. I still
32:40 a terrible job. The second phase , I'm going to pause there.
32:47 does iso mean same volumetric volume? same volume contraction phase right?
32:58 what we're saying here is that the is undergoing a contraction, right?
33:03 so the volume inside there inside that is going to stay the same.
33:08 what's gonna happen is now, I'm pressure inside that chamber. So the
33:12 is going to just want to try exit any way it can, but
33:16 can't go out the outflow because we that shut until the pressure inside the
33:20 gets high enough to open that So our outflow is shut, but
33:24 don't want it to go backwards. what happens to the inflow valve it
33:28 . So now the volume inside the is constant, right? So that's
33:35 it's a contraction because we're contracting but is not moving in either direction.
33:39 valves are closed. Third phase is outflow phase here. What we've done
33:44 we're still contracting the ventricle. The inside the ventricle becomes great enough.
33:48 it causes the outflow valve to So fluid can leave, but we're
33:52 to keep that back flow valve So fluid can't flow back into the
33:57 . So the inflow valve is the outflow valve is open. And
34:02 finally, the fourth phase is going be also isovolumetric, but we're not
34:07 . Now, we are relaxing after contraction, right? Because we squeezed
34:11 the blood out. So now we to go and relax. And so
34:15 going to happen is isovolumetric tells you valves are closed. The pressure inside
34:20 or or in the pulmonary artery is . So it wants to push the
34:24 backwards, that valve slams shut and pressure inside the chamber is greater than
34:29 pressure in the atria. So that shut. So you can see what
34:34 have, we have open and closed, closed, closed, and
34:38 , closed, closed. If you're to the first one being inflow,
34:42 second one being outflow, that's all in that little chart. I guess
34:54 have two of the same slides, I made the picture bigger. All
35:01 . This is the Wiggers diagram and looks kind of scary, but let's
35:08 kind of break it down real quick see what we have here up at
35:10 top. We have the ECG in middle here, we are looking at
35:14 in the different chambers and inside the valve or sorry, the receiving uh
35:20 uh artery. So we're going to on the left side of the
35:23 So what you see up there is aorta. So you can see the
35:26 inside the aorta. You can see here, the red represents the ventricular
35:30 . The blue represents the uh atrial . All right, here in the
35:37 , let's say exactly three or four . I don't know. That's your
35:40 , that's your love and your All right. And then down
35:43 this is volume and then these are pictures we already looked at dot All
35:47 diagrams have that, but sometimes they and then they're also showing you systems
35:51 dias so you can see where they up. All right. So what
35:55 do is we just line up everything we're just walking through the different structures
36:01 the different states. All right. the first state, what we refer
36:04 here is diastasis and diastasis simply says heart is at rest. All
36:09 So this is mid tri diastole, is rest. All right. So
36:14 here I am, this is mid . This is where we are over
36:18 at the front end of the So you can pick which side you
36:21 to look at. So we can ask the question about the different
36:25 right? So with regard to the cycle, we're not doing anything and
36:29 us at rest. So what's happening the valves? Well, when we're
36:33 ventricular diastole, we are moving blood the atria into the ventricles. Remember
36:40 ventricles at rest are receiving blood. . So that's what we see
36:45 If you look down here in terms pressure, the atrial pressure sits above
36:50 ventricular pressure. All right. I'm just gonna pause here for a
36:54 . I'm gonna have to wake you and say, do you guys remember
36:57 talking about? Pressure grading on Yes. Do things which way do
37:03 move from high pressure, low low pressure to high pressure, high
37:06 low? All right. So if ventricular dias when I'm at rest
37:12 the pressure inside the ventricle has to low. And since things are moving
37:17 the ventricle, that means there is greater in the atria than it is
37:22 the ventricle. Is it a lot ? Look at the picture? Is
37:26 a lot greater? No, in , they're very close to each
37:31 So what's happening is, is remember heart has already beat has already pumped
37:35 it's pushed blood out into the In this case, it's systemic
37:40 that blood coming out of the systemic is pushing the blood in front of
37:44 , which is pushing the blood in of it, which is pushing the
37:46 in front of it, which is in front of it coming all the
37:48 back to the atria of the And so the heart, the Atria
37:52 also in diace and it says, feel free to keep going because you
37:57 , we're receiving you. And so pressure is greater, but there's less
38:00 over there. So the blood flows the atria through the A V valve
38:05 down in through the ventricle. So where it's going. So what is
38:12 with regard to the volume of blood the ventricle? It increases, see
38:18 we're doing here. We're increasing. , notice over time, the rate
38:22 increase is slowing down. Ok. going to point that out here.
38:27 the flow like? Well, it's be slow because there's no real driving
38:32 . We're not pushing blood in. a passive flow resulting from the part
38:38 earlier from the cysto that we're not about right now. We're in
38:42 If relaxation is happening or is that means contraction occurred earlier. All
38:50 . So blood is flowing into the , the valve is open, flow
38:56 slow. We're moving from atrium and and the pressure is slowly increasing.
39:00 can see here, I'm slowly slowing, slowly increasing. It's increasing
39:05 the ventricle. Why? Because I'm more volume. Good old boils
39:11 the more fluid I add the greater pressure. All right. So the
39:16 is slowly going up, it's not up, it's slowly going up.
39:20 is it rising over the atrial No, it won't go over the
39:26 pressure because if it did, which would the blow blood flow, it
39:30 backwards. So the atrial pressure is because of the blood flowing into
39:34 But then it has nothing impeding it flowing into the ventricles. So it
39:38 going in, but that's causing the to rise over here. So both
39:41 them are rising together, but the pressure is higher than the ventricular
39:50 It doesn't go into um the artery again, the valve is closed on
39:56 backside. All right, that's the leaving valve. Now, the
40:01 thing that we're going to see right diastasis is we're going to get that
40:08 wave formed, right? So we're to activate or depolarize the atria when
40:13 happens, what do we see? gonna see contraction in the atrial muscle
40:17 I get contraction in the atrial I'm now increasing pressure on the
40:23 right? And so I'm going to the fluid out of the atrium.
40:28 that make sense? If I squeeze sponge fluid has to leave if I
40:34 pressure fluid flows and that's what's going here. So, you can see
40:39 the increase in the pressure as a of the P wave. And what
40:43 we see with regard to the volume the ventricle? What does it
40:48 Because there's this little hump, doesn't ? All right? Trying to think
40:57 an example. There's not a good . It was like trying to think
41:05 when you squeeze, you know, that last little bit out of maybe
41:08 you squeeze the toothpaste and get down that last little bit and you push
41:11 extra hard to get that last little . That's kind of what's going on
41:15 . So blood is naturally flowing from Atria to the ventricle because of those
41:19 gradients. But when the atria it's literally squeezing the last little bit
41:23 blood that's gonna find its way into ventricle. And so that's why you
41:26 this funky looking hump here at the . All right, that's what you're
41:31 there with regard to that volume. , the flow here is going to
41:35 fast. And why is it I just squeezed right. So the
41:40 is going to flow out faster because just increased the pressure. So I
41:43 pressure, it creates a pressure gradient steeper. So I'm going to get
41:47 flow. OK. So all those we learned about F equals delta P
41:52 V. That's what's going on here over R. Excuse me, not
41:57 . Um What else? Am I here. Oh, yeah. A
42:00 valve is still opened. If it open, we wouldn't be able to
42:04 flow to occur between the atria and ventricle. All right. So in
42:09 of these things, notice what we're . We're looking at the valves,
42:11 looking at the flow. What else we looking at? We're looking at
42:13 pressure and we're looking at the All right. So we've kind of
42:17 all those, right? And so gonna happen now is we've increased the
42:23 and now the atria is going to relaxing. And so when the atria
42:27 to relax the muscle there, what's have to happen? What happens to
42:30 pressure in the atria? When the relaxes, what happens to the
42:36 it decreases? So now what you is you have a volume of fluid
42:40 has a certain amount of pressure in . But remember you contract it and
42:44 you're reducing the pressure. So which does the volume want to go if
42:48 pressure was here that drove the volume way? Now that pressure decreases,
42:53 way is the volume gonna want to ? It's you want to go
42:55 Do we want the blood to go ? No. So what happens?
42:58 activity of the A B valve slams shut. So blood is now stuck
43:05 the chamber. OK. Now, is the isovolumetric contraction because when that
43:11 begins occurring something else begins occurring as . This is when we begin contracting
43:16 muscles of the ventricles. So the begin contracting and what happens to the
43:24 inside the ventricle. If I begin it goes up. And the first
43:29 it's gonna see is it's gonna feel resistance of the fluid. All
43:35 And we have two valves. We a valve that slams shut, that
43:38 open and we have another valve that's . But on the back side of
43:42 valve or really on the front side that valve, we have a whole
43:44 of blood desperately trying to come So I have to overcome the valve
43:50 here. In other words, I to overcome the pressure in the aorta
43:53 order to open that. So that's we have this isovolumetric contraction. Both
43:58 the valves are closed. So we contracting and we begin creating pressure inside
44:03 inside that. Now let's presume I'm strong. Can you guys imagine that
44:13 a moment if I squeeze this hard , do you think I can get
44:17 fluid to come out? Yes. . Now it is a metal container
44:24 I can try, I'll point I'm not gonna scorch you,
44:31 But you can see I can create type of contraction isometric, right?
44:40 am I increasing tension? Yes, I'm not getting anything to move,
44:44 I? And the reason is, because, well, in this
44:47 it happens to be the metal. if I had your little tiny plastic
44:51 , I could do the same couldn't I, and I could squeeze
44:54 thing and maybe I'm strong enough to get that one to pop.
44:58 But initially what would happen is it be isometric and so that tension is
45:04 up and building up. So the inside that chamber does what it rises
45:09 rises and rises and that's what we . It's shooting up. Now,
45:14 the pressure inside the uh Atria, sits down there and it's sitting nice
45:19 low and it's not doing much of . It's about where we left
45:23 OK. So we're not seeing much of pressure but in, in the
45:27 , but we're seeing this rapid rise ventricular pressure. Now, we don't
45:31 any movement of the fluid, Because both valves are shut. And
45:37 if you looked at the volume you'd say, oh, there's no
45:40 volume changes. So at the beginning cysto, um here, this
45:46 this would be the opposite of the of Diastole. We have a volume
45:49 fluid. Um And I think I'm come to this a little bit later
45:53 . So we'll, we'll deal with volume here in just a moment.
45:56 right. So that's, that's really function of what this is. It's
46:01 I sent my signal to the ventricular , the muscles contracted, they increased
46:06 pressure, but what happened was that slammed the valve shut. So I
46:11 the sound lub and then down what happened? Oh, the volume
46:16 change because there's no place for it go. That's what's going on
46:24 Eventually, I'm going to create enough . So that pressure overcomes the pressure
46:29 the artery. In this case, the aorta. And when that
46:35 the outflow valve opens, in this , it would be the aortic
46:39 So the aortic valve opens. And what happens is now we're going to
46:43 an outflow of fluid. So the of fluid inside my ventricle drops,
46:50 pressure still goes up because the muscles longer uh experience resistance instead. Now
46:55 are actually able to contract. So get a concentric um contraction. What
47:01 of uh con if it's concentric, would it be isotonic? Right?
47:09 we're, we're now able to maintain , but now we're getting change in
47:13 muscle size. And so we're ejecting this blood. So the volume of
47:17 in the ventricle drops, but the still keeps rising because now I'm still
47:23 that contraction and it's still going all way through. So we're seeing the
47:28 continue onward and notice the pressure inside ventricle is greater inside than the pressure
47:35 the aorta. Well, that would sense because which way is the blood
47:40 to the aorta? And as long the pressure in the order is smaller
47:44 the pressure of the ventricle. That's way the blood is going to
47:46 But if the pressure inside the order greater than the ventricle, then which
47:50 does the blood want to go So we're gonna keep squeezing until we
47:55 all that squeezing out. And then we're gonna do is we're going to
47:59 relaxing. Where do we begin relaxing on the ECG T wave? So
48:10 P is atrial D polar QR S ventricle D polar T is or ventricle
48:18 polar. So that's where we We come here to that last little
48:23 . So now we're going ah So what does the muscle do?
48:27 , it relaxes. So what happens the pressure? It drops? All
48:32 . And notice when it begins to , there's gonna be a point where
48:36 pressure inside the drops below the aortic . When the aortic pressure is
48:43 what's that going to cause the aortic to do? And you get your
48:50 sound dub. So Lup Dub are sounds of the doors slamming to your
48:57 . In other words, you can your heart is filled with an angry
49:01 and there's a bunch of door slamming on. All right. Now,
49:05 just pressured. That's all it is , it's driving it. And so
49:08 that door slams shut, notice the valve, the A V valve is
49:12 closed because the pressure inside the ventricle significantly higher than the pressure inside the
49:18 . So we're not going to open the A V valve, both valves
49:21 shut. So the volume inside the or the ventricle stays constant and there
49:28 are, we're down here, we're and it will remain constant until that
49:35 drops below the pressure inside the And when the pressure inside the atria
49:41 greater than the pressure inside the then that's when we open up the
49:45 V valve and blood begins flowing into ventricle again. All right. So
49:53 of the things you can do to you understand, all these different things
49:56 to draw Wigger diagram and just ask question, start with the ECG
50:01 Here's my QR ST OK. What's with regard to pressure and keeping the
50:07 places in mind? What's happening in A a what's happening in the
50:10 What's happening in the AORTA? What happens with the volume when the
50:14 is greater here than greater there? the volume inside the ventricle doing?
50:18 that's our frame of reference is the . So this is just another,
50:24 is I think the Wiggers or part the Wiggers diagram taken from your
50:29 And one of the things uh that talks about here that I was trying
50:32 mention, I was like, no, I'm gonna back up has
50:34 do with the volume of blood that's inside the ventricle. You are never
50:40 dry chambers, right? The Atria has blood in it. The ventricles
50:44 have blood in it. They're just full. All right. And so
50:48 we do is we say that there certain that you're going to find.
50:52 for example, um you are gonna moving as a, as a,
51:01 matter of course, about 100 and mils, 70 mills um that are
51:08 in that chamber will be ejected So it's like I'm pushing 100 and
51:12 mils in. And so when the squeezes 70 mills leave, and that
51:18 50 mils are gonna be left So what we call the part that
51:23 ejected is what is referred to as stroke volume. All right. So
51:28 this particular model, that would be mils, all right, the amount
51:34 fluid uh found at the end of and when it's diastole over, remember
51:40 over here before I begin contracting. the volume of fluid here is the
51:46 volume that I moved into the Well, what would that be?
51:51 , I moved 100 and 20 mils the ventricle. So that would be
51:54 end diastolic volume. And then when eject out that 70 mils, I'm
51:59 with 50 mils. So at the of Sicily, after ejection, right
52:04 I contracted, what is left over the ventricle is what is called the
52:10 systolic volume. So there's a relationship , it's mathematical and I have it
52:15 there. The stroke volume is equal the difference between the end diastolic and
52:18 end systolic volume. I'm gonna go to the picture here because I think
52:23 a little bit easier to see it , right. So here is
52:27 we said here's diastole, right? here is the end of diastole.
52:32 here it is all ventricular diastole. that volume of fluid right there that's
52:39 with the E is your end diastolic . That is the volume that the
52:44 is holding at its maximum in the . And then you get your
52:50 So you inject all this blood and you have this volume of blood that's
52:54 inside the ventricle after the valve that's your in systolic volume. So
53:00 difference between that point and that point there, that is your stroke volume
53:09 far. So good. All So we just went through an isovolumetric
53:16 , which is what I described That's the pressure dropping down. The
53:20 is relaxing. The pressure gets uh than the aortic pressure. So the
53:25 shuts, that's where we get the . The aortic pressure remains high.
53:30 actually gonna be dr being the it's now the driving force of fluid
53:34 the systemic circulation or PM if you're the other side of the heart.
53:38 and the muscle is relaxing because blood being injected into the systemic circulation pushing
53:43 all the way around, that blood to arrive in the Atria. So
53:47 happening to the pressure inside the It has to be rising,
53:53 So if it's low here and then pushing blood into it right again,
53:58 the ring around the Rosie everything is to itself. So if I'm pushing
54:02 out here, it has to arrive here. So the pressure inside the
54:05 is climbing. So there's gonna be point where the climbing atrial pressure rises
54:10 the falling ventricular pressure. And when happens, that's when we're gonna open
54:15 the valve again. So we're going see this massive flow very, very
54:21 . Um I want you guys to , can you hear that they're fluid
54:25 here? If I took off the and tipped it, tipped it
54:29 I don't know who this is. gonna be here till like the end
54:32 the semester. I'm just gonna put there and we'll see if it ever
54:34 lost or picked up if I tip over and the fluid flowed out,
54:39 would the most fluid leave at the or the end of me tipping it
54:45 ? It's at the beginning, Because all that pressure is driving the
54:49 out. So you're gonna see a , very quick fluid leaving the
54:53 same thing with the heart, all fluid wants to leave, it's just
54:57 for that valve to open. So soon as the valve open, most
55:01 the fluid just goes, I'm going that lower pressure and then the fluid
55:05 kind of trickles in the rest of time. And you can see that
55:10 our little picture here so fast and it slows down. If we go
55:14 this picture, it's a little bit . It's fast and then it slows
55:19 and then squeeze the atria. We get that little bump at the
55:24 . Now, this is actually pretty and it's beneficial what this does because
55:29 these laws of physics, what it that I can increase my heart rate
55:35 I'm actually decreasing diastolic time. But not changing how much blood I'm actually
55:40 to the heart because most of the going to the ventricle happens at the
55:45 end. What happens is even though diastolic time is going smaller and smaller
55:50 smaller. And what we're doing is looking at the green curve versus the
55:54 curve. So look the green curve the red curve look an awful lot
55:57 like on this front end, don't ? Would you agree with that?
56:02 , but look what happens. I of top out here, look how
56:04 change occurs over this period of Any change, a lot of
56:10 a little change, no change, minimal change, right? You
56:14 I'm just gonna show you the difference from this point to that point.
56:19 only about that much fluid, So there's very little activity. It's
56:25 fluid just kind of trickling in. , if I decrease diastolic time,
56:31 not losing fluid because I'm still going have my back end squeeze when the
56:36 contracts, which brings me right back to my original volume, it's kind
56:42 cool. So the laws of the reason you take those two horrible
56:47 rears its ugly head here. why that I'm not gonna tell you
56:52 map, I'm not gonna do the , but it demonstrates that the heart
56:56 taking advantage of some simple laws that follow and that's it right there.
57:06 a real hard sound thing thing. the two heart sounds are love and
57:11 . They, as I mentioned, represent the closing of the A B
57:15 first. That's the love sound. dub sound is the closing of the
57:19 semi lu valve. There are other sounds. This is there. Uh
57:24 the love and the dub are collectively to as S one and S
57:27 There's also an S3 and an S . These are rare. They are
57:32 of the galloping rhythms. I'm not ask you about that. But if
57:35 ever know if you know someone or who's had a galloping rhythm, this
57:39 just a recoil um that's occurring in heart. So that's why you hear
57:45 sound. It's not actual reclosing of of the valve. Well, it's
57:50 like this, that would be a to kind of think about it.
57:54 anyway, it just sits in between they are. And so you have
57:58 proto diastolic or presystolic. So, I'm not gonna ask you about
58:03 Um, if you have a question murmurs, you have a murmur.
58:06 know, someone with a murmur, that is is when the valves don't
58:11 properly. So, fluid leaks through valve and so it can make two
58:16 types of noises. One's a swishing , one's more of a gurgling
58:21 And so it depends upon the state the valve. Um whether it's stoic
58:25 want to open or if it kind falls backwards. All right.
58:36 So wickers is helpful because it shows the relationship of the electrical activity to
58:42 muscle activity to the pressure gradients that producing to the volumes that we're
58:47 That's why it's actually important to know . All right. I might ask
58:52 a question, what do you expect happen when you're an isovolumetric?
58:58 And so if you're able to just of walk through mentally through the
59:01 you should be able to go. , and really, if you're keeping
59:04 track of where the pressure is, good to go. Because if you
59:08 where high and low pressures are, know, the behavior of the
59:12 you know the behavior of the fluid gradients become like the linchpin to understanding
59:19 system and respiratory system when we get it. All right. So,
59:25 kind of keep those things in Now, what we'll see is when
59:32 push the blood out of the that pressure wave has now been moved
59:39 the ventricle into the aorta. All , we're gonna learn a little bit
59:43 about the order and, and its a little bit later. But the
59:47 here is that we have an elastic . It's not a stiff structure.
59:52 it's like a rubber band. So I push all that blood in
59:55 it just extends outward and absorbs all energy. And then it uses the
60:00 from that pressure to drive that fluid . So that's why we go through
60:05 bands of systolic and diastolic pressures inside aorta and why we can go and
60:11 in our wrists, that pressure, could probably measure that pressure down in
60:15 ankles too. And that's what this is just trying to show you is
60:19 we're seeing the band move along the . Um Now as you move away
60:31 the aorta, you're gonna get to different type of artery here, the
60:37 are stiffer. They don't have the that you see in the aorta.
60:43 so what they do is they actually resistance. And so what they're doing
60:47 they're fighting. And so what you up with is very high pressure on
60:51 end and very low pressure on the end. And so what does that
60:56 ? If you have a high pressure low pressure, you have a large
60:59 p, large pressure gradient. And now what we're going to do is
61:03 going to see flow moving quickly through structures, right? So the resistance
61:10 you're going to start meeting is going force that fluid to kind of change
61:16 behavior. It's still going to move . But you're now dealing with these
61:19 gradients. So we start off with pulsatile flow from the aorta and we
61:24 moving into what we call the named , the arteries that feed to the
61:28 . And so they start meeting that . And so they stop having pulsatile
61:33 and they start having a smoother And when they get that smoother
61:37 the flow basically begins drop precipitously, the pressure begins to drop precipitously.
61:43 that's what you're seeing here. And finally, what will happen is you
61:46 into the capillaries and these are so that they no longer have the resist
61:53 not the resistance, the pulsatile So fluid fluid flows through the capillaries
61:59 evenly. And then when you get to the veins, we're going to
62:02 to that a little bit later that end up dying off. And so
62:06 end up with the low point. what you're looking at here is you're
62:09 at the entire circuit. So if look at the ventricle and the
62:13 you have a very, very high . And because of all that resistance
62:17 change along the artery pathway and then through the cap players in the
62:22 you have uh right here in the , you have very low to zero
62:27 . So which way does blood always to flow right back to the
62:35 So your high is the ventricle, low is the atria, high
62:40 low to no pressure. So blood always flow. Now, it still
62:44 to fight some things. If you lying on your back, it would
62:47 easy because you're basically all the veins all the arteries or all the capillaries
62:51 on the same plane. But right , um do you think it's hard
62:54 pump blood from my big toe back to my heart? It's not even
62:58 . It's hard to move that Yeah, because it has to overcome
63:02 . But ignoring the gravity for a , the lowest point of pressure is
63:05 to be my atria. We start , we lose p pulsatile nature,
63:11 move to a smooth flow because of resistance. So we get this continuous
63:16 through the capillaries. There is a wave that forms in the veins,
63:22 a back flow. All right, kind of ignore this, but your
63:26 mentioned this and I just want to it to you So um you're gonna
63:30 this kind of up down thing. think I, yeah, I even
63:33 to make people memorize this and it's not worth the effort. But
63:37 you're doing is you're think about when year contracts it squeezes. Right.
63:42 so that means there's blood moving from viva trying to into the atrium,
63:46 there's no path. So you create pressure gradient there, right? And
63:51 every time something changes, there's gonna a slight pressure gradient. And that's
63:54 all this stuff really deals with. really what I wanna do is I
63:59 to kind of talk about the things contribute to the in the veins,
64:05 things that we need to do. again, I want you to think
64:08 you standing up. I want you think about fluid in your feet,
64:12 ? Or your blood in your veins your cap layers in your feet.
64:16 how does it overcome? How does get back to the heart? And
64:20 three things that help it first, retrograde action of a heartbeat. All
64:25 , we're going to deal with each these in turn. The second is
64:28 we call the respiratory pump. And third is the skeletal muscle pump.
64:34 when we talk about the skele or the the cardiovascular system, we say
64:37 the heart is the pump of the and it is it is the pump
64:41 the system there. Are no other pumps. But we have pump like
64:46 that's taking place throughout your body all time. And there are the,
64:49 are gonna be the benefactors. All . So with regard to the retrograde
64:54 ignoring all the different peaks and All right, when I squeeze my
65:00 , I create contraction, right? that's high pressure. And then when
65:04 relaxes, I keep, I create pressure. But when I create
65:09 that positive pressure, I'm also creating pressure in the Vena cava. So
65:14 pressure inside the vena cava is going , right? So if the pressure
65:19 the venna CBA goes up and then the atria relaxes it goes down,
65:23 created the same pressure gradient that I with or do I have a greater
65:27 or a lesser one? A greater ? So that backward pressure and that
65:33 of the blood to the heart is creating a greater pressure grade. And
65:37 when the atria relaxes the blood oh, I'm going right back in
65:40 as fast as I can. It faster than it would if it hadn't
65:45 . So that's a backwards pump. a suction pump, in essence,
65:50 kind of makes sense. So even the heart is a pump that
65:54 it's also a part, it's a that pulls blood into it because it
66:01 the gradients to pull the fluid in of cool. Huh probably never thought
66:07 that. All right. Number we're gonna come to respiration uh for
66:12 last two lectures of the class. right. When you breathe in,
66:17 don't have to do this. I'll do it for you when I breathe
66:20 . What does my chest do you ? Expand and go up? All
66:26 . So what did I do is increased the volume. So that dropped
66:31 pressure and when I dropped the what that did was that pulled uh
66:36 into my, into my lungs and that created a positive pressure in there
66:40 greater pressure, right? It equilibrated the atmosphere. But in terms of
66:44 my body did, it actually added . So when I push on
66:48 now, what am I doing is , I'm actually creating more pressure on
66:53 thoracic cage when it goes down. right. Now, once you think
66:56 what I just said about the when I contract the Atria, I
67:00 back pressure. And when I relax Atria, I create a sucking
67:05 So when I breathe in, what I do is I created a pressure
67:10 this space, right? And so happened is I'm pulling blood up towards
67:15 heart, right up into the thoracic because there's less pressure. When
67:23 when I created that greater volume, pulling blood from my lower extremities towards
67:28 chest. When I breathe out, doing two things, I'm pushing
67:36 right? And so that actually creates pressure into the abdomen. So it's
67:40 sucking pressure up into the abdomen. then what it does is it also
67:44 blood from the thoracic age into the . So what did my breathing do
67:52 very simple terms, it acted like pump. So I push and I
67:58 , push, suck, push, , kind of cool. So me
68:07 breathing, pulls blood towards my heart of the action of the muscles in
68:13 thoracic cage, not even my heart anything. Just me breathing. All
68:19 . Have you noticed that when you're in chairs, you wiggle your feet
68:21 lot. Have you noticed that? do you think you do that?
68:26 , blood it's to get your blood . You feel uncomfortable, you feel
68:29 pressure. Now you may not be of the pressure, but you do
68:33 that. So you wiggle your you move your feet around and stuff
68:36 that. But really what you're doing you're actually using your skeletal muscle
68:43 See the thing is, is that blood in the veins have very,
68:47 little pressure in them relative to It's still greater than the Atria.
68:53 blood wants to move from your veins the Atria, but that blood has
68:57 overcome the pull of gravity towards the . All right. Now, veins
69:06 are considered to be deep. In words, they're found deep within the
69:10 themselves. So they're surrounded by muscles they're usually running side by side with
69:14 arteries as well. But generally I you to think in terms here,
69:17 what you see in this picture is can see there's a vein and it
69:20 a muscle. All right. just trying to see what else we
69:24 here. Uh, um, we're gonna talk about the, there's
69:27 but I think I'm reserving the discussion the valves for when we talk about
69:31 blood vessels themselves. So we're ignoring for a moment inside the, inside
69:35 blood vessels. So you can imagine right now, if I'm standing
69:41 if there are no valves, the volume of blood at the bottom
69:45 my feet are sitting at the bottom a column of blood that sits above
69:50 all the way up. Right. there's blood in that vein at the
69:55 and then there's blood on top of and then there's blood on top of
69:57 and blood on top of that blood top of that all the way up
69:59 length of my leg. So if blood in my uh at the bottom
70:04 to get to my heart, it to overcome all that weight of blood
70:08 sits on top of it. All . And that's not an easy thing
70:11 do. So, what I need do is I need to reduce the
70:15 on top of it. All So how do I do that.
70:18 , my skeletal muscles when they what they do is they squeeze on
70:23 vein and they basically exclude the column blood. So the picture over here
70:28 showing you what it would look like there was no collusion. And then
70:31 I squeeze what happens, so you see the blood down here would have
70:39 pressure 100 millimeters to overcome. And distance because that's all blood sitting on
70:45 of it. But if I squeeze blood vessel, I only have this
70:50 of blood sitting on top of it and I only have to overcome that
70:53 pressure to move it forward. So how one of the ways that we
70:58 blood forward is by changing the the column by breaking it up into smaller
71:05 so that you're only moving a small of the blood forward in small
71:11 that kind of makes sense. the other half of this is that
71:14 do have valves and so the columns are broken up already in the small
71:20 . And what you can do is just move a unit to a different
71:25 of vein because of those valves. I don't have that stuff listed
71:28 And I'm like I said, I I reserved it for another lecture.
71:36 to help the blood get back to heart, it's not solely dependent upon
71:40 pumping action of the heart. We these three other mechanisms that help the
71:46 , the sucking portion of the right, the activity of the muscles
71:50 create suction back to the heart, respiratory pump, which is basically a
71:55 , pulling blood up to the thoracic . And then the skeletal muscle
72:00 which is pushing blood towards the heart squeezing on the veins themselves, trying
72:08 see what I got here. I I'm gonna stop on this slide.
72:13 And I think it's fine this I don't think we're either, I'm
72:16 bother talking about um because it does about the, the differences and how
72:23 a slight variation between the two year and the ventricles contracting. And
72:27 I don't think that's important anymore. what I want to show you in
72:30 , in this particular picture here is you the differences between the two sides
72:33 the heart. So we know the contract together, we know the ventricles
72:37 together, but they're not perfectly the on either side. And so the
72:42 for that is on, what are actually doing? So the left side
72:46 your, of your heart is pumping into which part of the body system
72:50 pulmonary left side is system. All . And then so right side is
72:55 . So let's just use me as model. How big is my pulmonary
72:59 relative to my systemic system? What you think small versus large? So
73:05 I need the same amount of muscle pump into the smaller system I knew
73:08 I have in the large system. . So that is being reflected here
73:12 the mus musculature of the heart, left side of the heart, you
73:15 see I have a lot of right. And so that muscle is
73:20 to overcome all the pressure of the circulation. The muscle you see on
73:26 right hand side, well, it all the pressure of the pulmonary.
73:29 just not the same amount of So it doesn't work as hard.
73:33 other thing I would show you is the bottom is look at how the
73:36 of the muscle fibers are. It's spiral bundle. So remember what I
73:40 is that when the heart beats, it's doing is it's squeezing. So
73:44 it's doing is you're pushing blood from atria and you're squeezing down here and
73:51 you're squeezing the ventricles so that you drive the blood up through the base
73:56 those uh arteries. And because of , the arrangement of this heart
74:02 this is how it develops, it off as straight and then it twists
74:05 to create these chambers so that it like this. Now, you're not
74:10 , if you look at a you wouldn't see this, you'd have
74:11 dissect it and tease it out. this is how it does and that's
74:15 it does it, this, this , uh, uh, twisting and
74:20 know I said this is the last but the one that you don't have
74:22 flip to it, you, you mean done and this just
74:26 it just shows you how, the, the heart is actually
74:31 And so when you talk about the , what it does is it squeezes
74:35 a tube and then what is uh, uh, that's on the
74:39 side and then the right side it kind of more like a bellows.
74:42 , what it's doing is it's, squeezing this way, kind of like
74:46 you can imagine an accordion, what I doing is I'm squeezing like
74:49 whereas this is squeezing like, so they're arranged slightly differently because of
74:55 way that they're contracting. So, , I just wanted to point that
75:00 when we come back, we will with something we already know the answer
75:05 and a couple of other things to of finish out the heart and then
75:08 start moving into the, the next . Now, I've told you
75:13 what do we have today a What are you going to go
75:19 You're going to go get a life you're going to go to the football
75:22 and scream and yell with your friends have fun. Then you go
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