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BIOL 3324 Human Physiology - 3324_lecture13_1014
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00:04 Yeah. Time to get in Right. Yeah. All right.
00:11 today, what we're gonna do is going to deal with uh electric conduction
00:15 the heart? We're gonna look at winners Diagram which scares everybody. But
00:19 actually once you learn wingers heart makes 100% sense. It's like the easiest
00:25 once you get past the oh my . It's scary. All right.
00:29 before we get we have our last , Do you guys read that
00:35 You're looking at me like you didn't it one More? Right? You
00:39 do it? Okay. It's all . It's nothing of the world.
00:45 right. So as we've done the two times, thoughts on the
00:53 Good bad, ugly. Okay. , boo What? Your you're nodding
00:58 head like so all of those are . All right. So you said
01:03 good. Why? Yeah, it Yeah, that's all right. Anyone
01:14 have your thoughts? Thoughts, thoughts, Yeah. Yes.
01:25 boring to get through. Oh Please don't be the person who writes
01:28 boring paper, Right? Yes. . The person who Uh huh.
01:37 . Mhm. Yeah. Okay. they didn't communicate well. Okay,
01:43 here thoughts over here? I couldn't that. Sorry. Yeah. And
01:50 while you're reading it. Okay, enough. I'm glad to see people
01:54 walking with umbrellas as I walked in room, I tried to see who
01:57 actually carrying umbrellas and Yeah. All . Anyone else thoughts? Anyone give
02:04 like really, really high rating first through now? It will get a
02:08 bad rating on the first time He's just So what made you mad
02:14 first time you read through it? did you give it such bad
02:18 Oh yeah. Okay. Mhm. . All right. So, so
02:36 of the things I said you've got be careful of is being too
02:40 right? Like you suck and you know sucks. And so I'm
02:43 give you all ones right? You you gotta be aware of that.
02:46 you also the other direction, This is, you know, it's
02:49 always easy to communicate, but the is like, I can't look at
02:52 that's good and go, man, awesome. Right? I mean there's
02:57 and there's nothing wrong with, We've been trained to believe that
03:01 I'll give you an example. This just in a conversation. I was
03:04 a meeting yesterday and someone like did work that was assigned them in the
03:10 right there. Like I did these . We looked at their things and
03:14 the personally he said, oh you a great job. I'm glad you
03:17 what I asked you to do. get an A. It's like I
03:20 say anything, but I'm like, doing what you did gives you the
03:25 score you can get. And that's the answer. Right? I mean
03:28 mediocre or expected and then there's above beyond. Right? And so that's
03:34 of this is what you kind of . But you rewarded them for giving
03:38 what you expected. And that's not case. You should be kind of
03:42 all right. You did what was of you check mark and remember what
03:46 what does the rubric say? It what is exceptional? What stands out
03:49 being really well done. That doesn't you're gonna get penalized if you're getting
03:54 that middle of the road, that of the road grade is still like
03:57 85 or 87. So it's not . It's just not wow.
04:04 As we said, we yawned. like, keep me awake. Please
04:10 something to excite me. All Anyone anyone else have any other thoughts
04:15 , you know. Wait a Why? Why didn't they did this
04:18 paper have any pictures of graphs or in it? Yeah. Were they
04:23 ? All right. So, so I've got your I've got control of
04:27 classroom right now, it's my Right? So just something. So
04:30 of the things that you're going to doing is you're gonna come across papers
04:33 don't have figures, right? You're come across paper. They do have
04:37 . And what you have to ask question is if it doesn't have figures
04:40 have been more helpful if paper did . And that's when you kind of
04:44 them. Right. And I'm saying I say deny doesn't mean slam
04:48 It's like it would have been helpful you put in some figures and maybe
04:51 gave you two here instead of a . All right? Or maybe it
04:54 the other direction is like, I didn't put it in figures.
04:58 didn't you didn't put in figures. didn't need figures. Your explanation was
05:02 enough so you can reward them for , right? So, the idea
05:05 is be critical with with what you're and what you're looking at and the
05:10 goes for because this is the biggest that is uh with regard to this
05:17 , you probably had to go deeper the literature. Older stuff.
05:21 Did you find yourself hitting things that earlier than 2010? Right. I
05:27 think somebody if they have stuff that older than 2010. All right.
05:32 mean, that's going to be part this particular assignment. You're allowed to
05:36 that. It doesn't mean you can't there. It's just we would really
05:39 it if you're really focusing on the stuff. But if there's no new
05:42 , you can't focus on that on . Right. That makes sense.
05:46 , so, the idea here you know, kind of look at
05:50 through that lens of how would I , how would this be a perfect
05:54 for me and then make those small from there. Four. Right.
06:03 instruction wise. All right. I'm gonna show my age now,
06:07 you ready? So in the old back when we did papers and rocks
06:12 the Flintstones when you put figures into paper, they always ask you to
06:16 them at the end of the paper that they can insert them for you
06:20 . And I haven't changed the They just slap them in if they
06:25 them into the text, just hey, you didn't fall instructional
06:28 Need a diagram for that, Yeah, yeah, yeah,
06:34 You say just see figure one or like that. I mean you basically
06:38 say here's my here's what I'm explaining then you can just put figure
06:41 right? And that should point them where ever figure what happens to be
06:45 speaking because I'm old and I follow rules. That's where you put it
06:50 the back. But I know we have really, really good software now
06:54 can insert things into a text That's right. Yes, sir.
07:00 , take care. So again, remember I said, I'm not expecting
07:05 to be artists. Right? You you can, I'm gonna just put
07:09 quotation borrow someone else's figure. That perfectly fair. But if you do
07:15 , you need to footnote in that right? In the figure legend that
07:20 got it from whatever source you don't their figure legend because they're using a
07:25 to describe something in their text. using the figure to describe something in
07:29 text. So just you know, here's a picture of the sun and
07:34 can put in your figure legend. is a picture of the sun.
07:36 then you put the reference from where came from. All right. Sound
07:41 . All right. You want to what this one scored is? Do
07:44 guys care? Mhm, escorted about 77. All right. Um Lots
07:52 fours. Lots of threes, a of twos, So threes,
07:58 threes, bunch of twos there at bottom. So yeah, so that's
08:04 about an average paper. Right? , that's what it felt like to
08:08 , it was like an average So, if you felt like it
08:11 an average paper, you did If you thought it was a great
08:13 , maybe bring it back a little . If you thought it was a
08:16 paper, bump it up a little . That makes sense. Mhm.
08:22 , what is the paper due Okay. All right, this is
08:27 good place to ask you this question we get on. Uh Do you
08:31 like to work on the weekends or you guys I mean, just generally
08:34 , I'm not I'm not changing anything like to work on the weekend or
08:37 you rather get things off your desk a friday? You guys like
08:42 like weekend. I mean, I'm to figure out how do I do
08:45 for the future because I hate things on my desk on the weekend because
08:50 means someone has an expectation that I'm be working when I want to have
08:55 . All right. My life is 40 hours a week. Close to
09:02 hours a week. But you know I'm saying? So All right.
09:05 if you guys like weekend stuff. huh. Poor future classes. I'm
09:13 changing dates now. That just screws up unless I have to. All
09:17 . Um I just wanted an opinion from your perspective, Hearts. I
09:22 to talk about hearts. Yes. Maximum working for the abstract was
09:28 Always to 50. Yeah. However words you need in order to explain
09:33 in there, so that your readers papers about 150. It could
09:40 Yeah. So generally speaking, I about all the papers that you've looked
09:44 , right, pick them up. thing you do read the title
09:47 Maybe then you read the abstract. know if the after explains what you
09:50 , you can go into the paper throw it away if it doesn't,
09:52 like damn it. And then you to kind of start reading through.
09:58 ? I'm hoping this is recording. signal numbers moving, but the last
10:01 quit it like 23 minutes. So don't know today. What we're gonna
10:06 is we're gonna talk about the heart heart conduction. Alright. First
10:10 whenever you look at any sort of textbook, there are three colors that
10:13 use regularly read for oxygenated blood blue for the oxy blood. Yellow is
10:19 nerves. All right. That's that's general rule. And you're going to
10:24 pictures like this in books where they these things kind of yellow. All
10:29 . These pathways and what these pathways the conduction system of the heart.
10:33 are not nerves. This is why kind of like what these guys
10:36 which they made them black and surrounded in with yellow. Alright. It's
10:40 not the best. I mean, guess they could have used a different
10:43 , but purple's kind of reserved for blood green lymphatic. So there's all
10:50 of it's just hard to figure out color. And so why bring this
10:54 is because what we're looking at here the conduction system is a series of
10:58 cells that are linked to each other allows the heart to conduct an action
11:04 through all the muscle fibers. All . There are four basic areas where
11:09 have the specialized contract tiles that are contract ourselves, pacemaker cells that are
11:17 for creating the heart beat of a . All right. And these are
11:21 forwards the essay. No, the . No, the bundle of his
11:24 kenji fibers. And I know just down the list isn't very helpful.
11:27 , let me just show you where things are S A node resides in
11:31 superior part of the right atrium. A. B. Note sits in
11:35 septum between the two atria two So if you think of our heart
11:39 we drew that cross kind of right in the middle of that. Down
11:45 middle of the septum we have a of fibers. These are the bundle
11:48 hiss or his. I don't know . I don't know if it's named
11:52 a person or what? Maybe it's sound it made when they pop the
11:56 open. Who knows? Right. basically these bundles go down and then
12:00 they do is they spread out around external surface of the ventricles that they
12:04 to Perkins, the fibers. All . And so when we're talking about
12:09 , what we're talking about is producing action potential up here or in here
12:13 along those lines. That's going to the heart to beat. Now,
12:17 said or or or but what we're to see here is that really the
12:22 pacemaker of the heart is the A note. And really all the
12:27 of them are responsive to what the . A note is doing. All
12:31 . Of course. It's not going play my game. There we
12:36 So the S. A node is pacemaker. All right. And so
12:40 the one that decides for the most what the rate of the heart is
12:43 to be. And if you read the textbooks that they have for like
12:48 freshman and stuff, it's like think trains and having four engines in a
12:52 when the first engine is the one decides the rate and then if the
12:55 engine blows out, then it's the one and so on and so
12:57 And really you can imagine that what have here. We have these cells
13:01 have their own natural pace that they contract that. But because they're all
13:07 to each other, they're going to to the one that's the lead
13:11 The essay. No, that's going produce the action potentials that then influence
13:16 rest of them down the line. , once an action potential is produced
13:19 here, it's going to travel along these different pathways and down and around
13:24 heart to create the uh going to the exponential so that the muscles actually
13:30 contract. All right. But if break that one, then the next
13:35 note and it's not necessarily the V. Note. All right.
13:39 sorry. That circle should have been here, but at some time I
13:41 the picture and I just noticed that . All right. That should be
13:46 . That should be over that or like that. I'm throwing this picture
13:51 here so that you can visualize, the bottom here for a moment.
13:55 , We're actually we're not going to about that. That's just showing you
13:58 the thresholds uh decrease over distance. ? But what this is basically showing
14:04 is how these cells are interconnected, ? So, these would be cardiac
14:08 cells and you can see the action is basically moving through these electrical
14:15 And so what's happening is once I one, each cell is gonna initially
14:20 going to conduct to the next cell it's attached to all the way down
14:24 line. Now, when you think the heart, it's basically just
14:32 Have any This is this is kind a gross question, but it's actually
14:35 a good question. Has anyone ever heart? Yeah, a couple of
14:40 . Yeah. All right. What it taste like? It tastes like
14:45 brains. Oh, tasted rubbery. felt rubbery. Right? That's just
14:49 it's a really, really tough It's a very It's But it's it's
14:53 just muscle, right? I it's cardiac muscle, but it's just
14:57 . So, when you eat What a steak? It's muscle.
15:02 right. Everyone starts thinking about the a second. I'm eating. I'm
15:05 a critter. Yes, you You're eating a crater. Could be
15:07 big crater. A small crater. you're eating a critter. This
15:10 We sit creators. Alright, What a heart to heart is muscle?
15:15 very lean muscle. All right. can actually So, I actually attended
15:20 conference once where there was a class was being taught there were demonstrating.
15:24 said this is what we do in Mp class. And it was some
15:27 from East texas, Tyler texas and says we talk about the heart and
15:31 go down to the hee bee and go buy me a big old cow
15:34 and you go by cowhearted HCB. open it up because that's what FDA
15:38 you to make sure there's no worms it and it's really, really
15:41 And then we talk about all the of the heart and then what we
15:44 is we throw it on the grill sear it up and then I can
15:48 it to my class. Whoever wants try a piece they do. And
15:51 course all the people are like he you like so he's sitting there telling
15:54 stuff and he's cooking the heart while telling the story. And then he
15:57 all these two picks. Go try peace of heart. You can
16:01 there and look at it for a that I'm not gonna be whip.
16:03 you just try and what it's just like fajita that hasn't been properly marinated
16:10 a long period of time. it doesn't have a taste like
16:15 right? And that's what I want to think about when you think about
16:18 heart and there's two different types of here. Right? When we think
16:22 skeletal muscle, we had a vision what skeletal muscle look like These
16:26 really long cells. It's different. are actually very, very small
16:29 And there's two types of cells that located here. One is the pacemaker
16:34 . The second is the contract I'll . So we have one cell that's
16:37 for the contraction of the heart. . And we have one that's telling
16:42 cells that do the contracting when the . So the pacemaker cells and the
16:46 cells are the ones that are not . They're the first one that we're
16:51 to identify as the heart is developing they show up and they start beating
16:55 before there is an actual heart All right. And they have this
17:00 ability to actually contract and to produce sort of electrical conduction. And as
17:05 heart developed, that the other muscles are added onto it then respond to
17:09 contractions. Alright. And those would the contract. I'll sells 99% of
17:14 muscles in the heart. Are these ourselves? So, they do the
17:19 work. This one is one that the pacemaker. This is one that
17:24 and produces the contraction in response to action potential produced up in here.
17:31 , how do these produce action I'm glad you asked you don't
17:38 All right. What we have here we have a cell that has these
17:44 channels are allowed to go through a action potential. You thought you guys
17:49 done with action potentials, nope. . Got one more after this
17:54 All right. Now, there are ions. When you think about the
17:57 and think about action potentials, there's going to be three ions sodium potassium
18:00 calcium. All right. For the sell what we have is we have
18:06 channels. One that's called the funny . Alright. It produces a funny
18:13 . You're I'm dead serious. That's name of it. That's what the
18:17 . Stands for. Funny. All . You don't believe me go to
18:21 and look it up. These are on a specialized channel. The
18:25 C. N. I'm not going get this right. It's hyper
18:29 activated cyclic nucleotide gated channel. don't worry about it. Alright.
18:41 produces a funny current. In other . What happens is is when you
18:46 into a hyper polarized state that causes channel to open. All right,
18:51 all we're caring about. And when channel opens, it's gonna allow sodium
18:57 actually kind of run in. It allows potassium to run out. All
19:01 . But in essence, that's the type of challenge. So, you're
19:04 sleep. A slow deep polarization in process. We're also going to start
19:09 the opening of of some calcium channels well. As well as some sodium
19:13 , we actually have a voltage gated channel which helps to speed up the
19:18 at which this is going. you can imagine our normal rate of
19:21 the polarization would be fairly slow with a funny channel. But what we
19:25 is because we have sodium channels. actually changes the rate and we begin
19:30 faster. Third type of channel is calcium channel. All right. And
19:36 is again responding to the change employers voltage gated channels. Alright, there's
19:41 . Type calcium channel. So, you've ever learned about L. Type
19:44 T. Type and I don't think ever touched you. But if they
19:46 come up One is fast one slow types are the slower types. All
19:53 . L for long. All And so what they do is right
19:57 this area is that's when we actually opening nose and eventually we're going to
20:01 up all those and then boom, shoots up. And so now we
20:05 see the spike of our action And then all those channels close.
20:10 then lastly, we have a potassium that causes us to re polarize and
20:15 hyper polarized. And then we get the bottom of the hyper polarization.
20:18 repeat. So, you can think it like this sodium calcium potassium sodium
20:27 potassium over and over and over again terms of permeability. All right.
20:32 calcium are flowing into the cells to deep polarization, potassium causes re polarization
20:39 ultimately hyper polarization which starts the cycle over again. So, can you
20:44 the pattern here. Fire relax. relax. fire relaxes that apace.
20:54 like in one of the four Yes, sir. So is
21:01 Yeah it is. It's that C. N channel that I said
21:04 . I said I'm going to get hyper polarized, hyper polarizing, activated
21:12 nucleotide gated channel. Something like It's yeah. So once you get
21:19 polarized, that's one of the opens . It's the house sodium first then
21:26 sodium is going to remain open. ? And then the calcium and then
21:31 at this point all the calcium channels and then off you go running to
21:34 races then they slam shut and then down again because of potassium channels
21:40 Yeah. Yes ma'am. Why it's stand at -60. So, you're
21:50 a chicken and egg question which I know the answer to why the reason
21:55 because these channels being in place, islands that are involved. But the
21:58 is which came first and why wrong to ask. I guarantee you there's
22:05 who knows the answer that, but this one. All right. So
22:08 we see the patio, sir? . It would be like normally you'd
22:15 for neurons about -70. Right. , so why comes down that way
22:21 again? It has to do with really the it's to be honest,
22:25 that I'm thinking about it. Remember all learn this and you've quickly dumped
22:29 because I said it wasn't so But it has to do with the
22:31 Hodgkins cats equation which is basically The availability of number of ions or
22:37 number of channels as well as the relative concentration of ions on either
22:43 But I don't know why that chose . All right. Reporters. What
22:54 ? Mhm. Problem. Well, suspect what we would see if it
23:00 up is that we'd have an equally enough signal to bring it back down
23:04 . Otherwise the heart would stop doing it does. Right? And so
23:08 mean, could you have extra Yeah, But I don't think the
23:12 would be alive. I don't think would be something that just pops up
23:15 then kills you think literally would be you don't exist as an organism.
23:19 swear. I'm guessing I can't speak sure. All right. So,
23:23 a pacemaker. Right. And that is producing an action potential that's being
23:29 to other pacemaker cells and it's being to other countries or to the
23:34 I'll cells. Okay, This is action potential of a contract. I'll
23:40 . All right. Now, you look at this and kind of freak
23:42 . But really this is actually one the easiest type of action potentials.
23:46 can see And I'm gonna draw it here in black. Hopefully you guys
23:48 see if I need to I'll go there. But basically it goes up
23:52 down a little bit comes across, down. Alright, so resting potential
23:57 a leg up a little bit of up and then kind of come down
24:01 little bit then it's flat and then comes down. All right,
24:05 rapid rising phase. We have a phase. Rapid falling phase. You
24:11 that up there in the picture, rising plateau fall. three ions
24:17 different channels. Alright, over on rapid rising. It's going to be
24:21 and calcium. Is that different than first one we looked at?
24:25 Okay, that's good. So, got sodium and calcium. Alright,
24:30 channels take calcium, take it up and then the sodium channel slam
24:34 So we kind of fall. But we're going to open up and sustain
24:38 plateau through the opening of and sustaining calcium channel staying open. So
24:45 calcium and calcium. And what do think This one is potassium? All
24:53 , so, that's what the action looks like. So, it's actually
24:56 again it's kind of a simple It's all right. I'm a rapid
24:59 . So deep polarization with sodium and sodium channels close maintain the plateau with
25:06 . Turn off the calcium channels open channels down. I go return back
25:10 rest and so that's the exponential that's inside one of these contract ourselves and
25:17 passed on to other contract I'll cells they're attached to. Okay.
25:23 no, there's a reason why contract have this really weird looking plateau,
25:32 ? And this expanded action potential. it has to do with refractory periods
25:37 the purpose of the part. What's purpose of the heart? What was
25:41 basic thing that we said? The does it pumps so pump has to
25:46 through two stages. Right contraction contraction relaxation. Can you feel your
25:52 heartbeat right now? I mean you your hand on your heart, you
25:55 , he or whatever. Can you it's thump, thump, rest,
25:59 , thump, rest, thump, , rest right over and over and
26:05 again. Now I want a you the picture. You know one
26:09 two ways. Think of someone that attracted to or you can think of
26:12 exciting or maybe a scary movie because heard scary movies earlier. Right.
26:15 is your heart rate going to The, press the, press
26:19 press the, press the, press press right there. Still rest in
26:26 . Oh, when you're thump, , that's go see a physician.
26:32 clear that one right out of my . What we're doing here is we
26:38 have a period of time that forces heart to go through the contraction and
26:42 relaxation period and giving enough room to another heartbeat. So imagine even going
26:48 now. Picture for a second sprinting . Oh I don't know ever.
26:52 would you, what would your heart The rest of them? I mean
26:55 can't talk fast enough to be thump, thump, thump,
26:57 thump, thump, thump, 220 a minute. There's still rest period
27:01 there, Right. What happens if take out the rest period? What
27:05 happen to the heart parking? That's that's a heart failure. It's
27:10 that's technique of the heart. Tetanus the heart, right? In other
27:13 , if I sustain a contraction, tetanus, that's the same thing that
27:17 skeletal muscles do sustained contraction. And means I'm not moving blood. That
27:22 bad things are gonna happen. All . So, what the refractory period
27:27 is or what what this plateau It establishes a refractory period for the
27:33 I'll cells. Right. So, we're doing is we're stacking two things
27:37 this picture, or at least in picture right here, trying to find
27:42 different color. So we can see . The black in my picture over
27:46 represents the action potential. If we at contraction and relaxation in the heart
27:53 , we see the contraction and then see relaxation. All right,
27:58 if I speed up the heart right? I'm not shrinking this,
28:03 shrinking the time between this one and next action potential. So that means
28:08 will always have a contraction and relaxation before the next contraction relaxation.
28:18 this shape of action potential ensures a elongated refractory period to ensure that the
28:25 goes through full contraction and relaxation that never sustains contraction kind of cool.
28:34 your heart would stop doing what it's to do and that's what that picture
28:41 showing you here. The blue, your deep polarization, red is contraction
28:46 . The green represents a refractory. if things start in the S.
28:56 . Node go from the say no the A. V. Not
28:58 B. Note of the bundle of bundle of history of working the
29:00 There's got to be a pathway through those cells are actually or that signals
29:05 traveling right now. Remember there are cells along these pathways. Right?
29:12 the first thing that's gonna happen is get that s a note to
29:16 In other words, the exponential gets in the s. A note.
29:19 what it's gonna do is it's gonna throughout all the contract I'll cells as
29:23 as pacemaker cells that are located within atrial. All right. So that's
29:27 on the right hand side. So I'm only contracting this side, that's
29:32 gonna do me a lot of good what's happening on the other side of
29:34 heart, is it contracting what we know and then all of a sudden
29:38 whole ring around the rosie thing that talking about would just cease to
29:41 basically. There's no place to push blood. So that's bad. So
29:45 things first we're going to send a from the right atrium over to the
29:49 atrium so that the right and the atrium are in sync. They contract
29:54 . This is referred to as the atrial pathway. All right. So
30:01 it's going from here to over So those both eight year contract at
30:04 same time, I mean they're both blood simultaneously into their respective ventricles.
30:09 right. And you're presuming? Of at this point the Aricept the ventricles
30:12 receptive to receiving blood. The second that we're going to send is we're
30:17 go from the essay know down to A. V. Note. This
30:20 the internal pathway. All right. you can see there's these pacemaker cells
30:24 what the arrows are kind of representing say there's a pathway that leads
30:29 Now what this does is it ensures the atria are going to contract before
30:35 ventricles do. So both of them contracting together. Then I send a
30:39 down to the A. V. , the atrial ventricular node. And
30:44 now what I'm gonna get to the delay and then that signal is then
30:47 to move on word. But what's now is I've contrived sent a signal
30:51 both atria. The signal arrives before actual contraction occurs, contractions occurred
30:58 That signal is simultaneously means into the and there's a delay That's going to
31:05 the two ATIA contract before the ventricles . All right. And I think
31:10 what the next slide is. Like Mhm. They look tired
31:21 Yes. So, so again, dealing with a positive and negative.
31:25 ? So you're while the two paddles usually being put up like this,
31:29 probably know better than I would. ? Where when you're paddling a uh
31:35 used? Yes. You don't The the little Oh yeah. You're using
31:41 now. Yeah. But in it's in two different spots.
31:45 And what you're doing is you're creating conductive pathway, right? And you're
31:49 using a lot of electricity, but don't have a lot of do you
31:54 how many votes it is results? volts. How much is coming out
32:07 the wall? Uh huh. Right. So, basically what you're
32:13 is just trying to get enough to those cells to kind of start working
32:17 again again. Why I'm deferring over is because I do not have expertise
32:23 that. He's in the medical No, but you but you do
32:27 . I mean, that's that's different me than going so Well, I
32:30 about it once or twice. All . Better to ask someone who's done
32:35 than someone who's just thought about Yeah, these passes. Uh
32:43 So, So, what we're gonna here in just a moment, the
32:46 are opening, closing in response to gradients. They're not responding at all
32:51 any sort of electrical signal, which kind of cool. Right.
32:54 we're basically we have a passive system dependent upon the activity of the heart
32:58 the flow of the blood to do job to prevent blood from flowing the
33:01 way flowing the wrong way, not . All right. So the
33:06 B. Note. As I said there's a delay. So the existential
33:11 actually conducted rather slowly. There's a . And this ensures that the atria
33:15 first or contract first before the ventricles . Then once the A.
33:21 Note uh sends its signal. Then bundle of hiss basically goes right down
33:25 middle. So you can see this where I'm promising you the yellow.
33:29 ? Those are not nerves. Those muscle cells. Right? And so
33:33 signal travels down through that septum and back out. Around on all those
33:40 I'll cells that make up the wall the heart. And so it's a
33:43 fast conduction, Right? I conduction occurs first and then contraction occurs
33:50 . Right? And so you get first and then they're like,
33:54 time to contract. And then both contract simultaneously. So they're ejecting blood
33:58 to the system and to the pulmonary at the same time pushing the blood
34:02 front of them forward so that the ready to receive or can receive that
34:08 for that blood. All right. , we get a coordinated contraction.
34:13 so if you kind of want to this, this is kind of what
34:17 looks like you can see it's traveling a bundle his down around the
34:21 And now what we're gonna do is going to get uh deplore ization and
34:26 . All right. So just just nomenclature stuff. This is the
34:31 When you think of an apex, think of the top point on top
34:33 a mountain. But the apex here where we took the mountain and flipped
34:37 upside down to the point part is the bottom which really really is confusing
34:43 Mhm. They refused refer to this the base of the heart. Which
34:47 like okay, so now let's use little bit of our brain power and
34:54 think about sympathetic and parasympathetic activity. right. You see someone cute?
34:59 heart goes pitter pat, doesn't Right. When you go to a
35:02 movie, what is your heart goes pat? Right. And then after
35:05 scary person gets off the T. . Or that cute person goes walking
35:08 , your heart slows back down Right? And then when you're sitting
35:12 listening my lecture, what does your do slows down? There you
35:16 And what you're doing is you're fighting to keep your eyes open.
35:21 As I look around the room. right. So what are we doing
35:27 ? Well remember what that that uh represents, right, It represents sodium
35:35 and potassium. And so when you're about sympathetic activity, what you're gonna
35:39 is you're going to speed up your to threshold. So, what that
35:43 is you're going to increase permeability to calcium. How would you increase
35:50 What's what's one way? How do make How do you make it easier
35:54 more people to come in and out this room? More channels is what
35:58 looking for. I mean, you're . Opening closing doors. That's
36:00 But if you exhausted all your you need to have more doors.
36:04 so that's the first thing we're going add in sodium calcium channels and it
36:08 take long to this. That's what do. And then with regard to
36:12 get being able to get to threshold , why don't we not be polarized
36:16 hyper polarized as much as we used ? So we're gonna do is we're
36:19 to reduce potassium permeability. So instead dropping way way down here instead,
36:26 just dropping halfway as an example. it doesn't take as long to get
36:30 threshold because we don't have as far go. And by the way,
36:34 also increased permeability. So we rise lot faster. So sodium and calcium
36:39 increased potassium decreased. That's sympathetic. we end up firing more frequently.
36:49 what this is showing you gray is normal red is showing you how how
36:53 speeding up the rate, we haven't as low and we're climbing faster.
36:59 right. So, if that's true sympathetic, what do you think the
37:03 is the opposite? Right, decreased and calcium permeability, increased potassium
37:10 We spend more time in a hyper state takes longer for us to get
37:14 threshold. But once we get everything's all hunky dory. But then
37:18 right back down again. So, why the heart beats slower and all
37:25 doing is we're adjusting between those two . It's not too hard. It's
37:29 when you look at the picture isn't it? All right. Move
37:36 to the big here. All I'm not going to ask you questions
37:40 where we position stuff. I'm just to use I'm going to give an
37:43 here so that you can understand what's on. All right. So,
37:47 we're doing when we're looking at we're looking at the electrical currents in
37:52 muscle. We are not looking at action potentials. All right.
37:56 what this is we have a series leads that are between two points.
38:00 ? So, it's between Point And Point B. And what we're
38:03 is we're asking the question is what the current look like between these two
38:07 . All right. So, the of the electrical activity in the fluids
38:12 surround all this tissue. Right. , you're asking the question when you're
38:16 you're paddling somebody, you know what's on? Is its electrical current traveling
38:20 the fluids of your body between those points of the two paddles.
38:24 And so it's kind of the same . I'm just recording what's going on
38:27 terms of current. All right. the spread of the activity of the
38:32 , right? It's not I mean that deep polarization, it is not
38:37 action potentials. So, it's not looking at just this. Although we
38:41 see what the some of these look . That's what this is really
38:45 All right. So what it it provides an assessment of the electrical
38:52 that are occurring. And this is example of a perfect, beautiful.
38:57 . 100% wonderfully. CG Have you seen a perfect example of an
39:01 E. G. In the entire that you've worked? No, you'll
39:04 and take classes. I'll show you and then they'll say, okay,
39:07 slap those leads onto your bodies and get stuff that you've never seen
39:12 Alright. Actually, I don't know one of you emailed me but one
39:16 you emailed me said wait a Isn't the book say there's six.
39:20 was that you Okay. You said six. I'm like six shows how
39:24 I've read the book As 12345. it's like no, there's a you
39:31 . And it was like in the even said we think it's this so
39:37 wave. Okay, sure. I'll it. Alright. Little trivia?
39:41 thing. Um Well, I'll get the tribute thing in just a
39:44 So if you're wondering so the way I like to think about this because
39:49 a big football fan. All I'm not a big NFL fan but
39:52 am a big college football fan. have been actually right now because my
39:56 are in high school. My big school football fan too. I'm having
39:59 having a blast. I went to small high school, we didn't have
40:01 friday night lights. My kids go a big high school. We have
40:05 friday night lights. Anyway when you a football game on tv, whenever
40:11 any sort of play that goes co , right, what do they
40:15 Stop play? And the ref goes look at the little screen and then
40:19 announcers sit there and they show you play from 40 different angles. You
40:25 ? Look at it from this look at it this way, look
40:27 this way, look at this All of those are basically cameras pointing
40:32 the exact same thing right? To you a sense of what's going on
40:37 what the leads are on. G. Is basically the same
40:40 It's all pointing at the heart and asking what is the electrical activity look
40:44 from this angle from this angle from angle from that angle, from this
40:49 so on and so on and so . Right? And then what the
40:52 does that you're plugged into basically takes and creates a composite image so that
40:56 get a composite image that looks like picture that I just showed you.
41:00 if you look at all those look the first lead, the second
41:03 That secondly looks a lot like the thing I just showed you, but
41:06 still something missing up there. You ? None of those match the big
41:12 . There's also some leads that go your chest as well. Again,
41:16 not gonna ask you where they I promise you there is.
41:19 This is not me trying to trick . All right. What ultimately happens
41:24 you get this composite image of this what an E. G. Should
41:29 like. That's the electrocardiogram. And you can see it has five
41:36 book says 65 ways. All Yeah. So, what we have
41:41 we have the P wave. All . That's the first one. We
41:47 the queue. They are the We kind of combine it together and
41:50 we have the T. Wave. then you imagine there'd be a
41:53 Wave if we talked about it and it ever showed up. Okay.
41:57 the fun trivia part. Where do think the names came from?
42:03 they did. They came from the . Sure, but why P does
42:06 want to wager a guess what do think? Yeah. Second. Thank
42:15 . No, that's that's actually a good guess. Most people just stare
42:19 me. So, I'm glad you are playing my game today. All
42:22 . Have you ever noticed in Everything starts with the letter A.
42:25 the number one or an alpha? noticed that? Yeah. So the
42:29 who's doing research said, hey, don't want to do that.
42:31 we start in the middle of the with the letter P. Then.
42:37 nice. Finally something interesting. that's why we got P.
42:41 R. S. T. And oh, it repeats itself.
42:46 Yeah. P. Q. S. T. That's it.
42:49 , that's where it comes from. right now these waves represent things that
42:55 occurring in the heart. So the wave is the atrial deep polarization.
43:00 right. So that's that action potential across that entire structure. The QRS
43:06 ventricular deep polarization. The T. represents ventricular re polarization. What are
43:11 missing? True atrial re polarization. , It's like where is it?
43:20 right. I'll tell you where it . It's up there. You just
43:24 see it. It's hiding by that um Cure estoy alright, how to
43:32 this. I've got three boys, of them now in high school,
43:37 he's as tall as I am. , he doesn't count. I've got
43:40 10 year olds. All my boys like me. All right there.
43:44 cuter. And their hair is in gray yet and they don't wear as
43:49 as I do. And all the sad things that happens when you get
43:52 . Mhm. All right. So gonna take my youngest the younger to
43:57 twins. Right? So I'm gonna the youngest who really looks like
44:00 Let's say I brought him into the and I put them up here on
44:03 next to me. He'd look at and he'd go and he'd run right
44:07 right? And that's where he would for the rest of the class.
44:10 may pick out every now and then it's not likely. He probably just
44:13 there and huddle because he's really And so when I moved like this
44:17 move so that you would never see . He's still there. But my
44:24 hides his mass. And that's what's on here. Is that QRS is
44:29 the ventricle which has more muscular And so it has a much larger
44:36 than the little tiny atrial deep polarization re polarization wave. I mean look
44:42 this T. Wave relative to that . R. S. Right?
44:45 this is deep polarization that's re polarization if that's deep polarization how small would
44:51 re polarization BB itsy bitsy. So be like and it's completely hidden by
44:56 QRS. So it's there. It's you can't see it. Yeah like
45:02 , right? It's just hidden, ? I haven't seen anything that says
45:11 oh you can you can pull it . But I bet you with one
45:13 those leads it probably is looking specifically that. But again, I don't
45:19 there and analyze each of those leads I don't think we need to know
45:22 stuff. I think that's beyond what's to us. Now. If you
45:25 a cardiologist you probably should know those but not for us. All right
45:33 what they also represent? They represent just this deep polarization but they also
45:40 these periods of time where nothing is going on. In other words there's
45:44 current because remember all that stuff represents . So for example the period between
45:49 P. And the r. Really P. And the queue represents no
45:54 . It's the baby nettle delay. what we have is we have atrial
45:58 polarization. Then we have a delay the ventricles go through their deep
46:04 Right? We have the S. . Segment. Right? Esty represents
46:10 right? There. All right? if this is re polarization, this
46:14 the period of time when a contraction taking place. Right? And also
46:21 maybe no delay. That's represented by PQ also represents a contraction taking place
46:26 then the T. P. The period of time between the
46:28 Wave and the beginning of the P represents the period the period of time
46:33 the heart is at rest completely. I'm going to draw something over here
46:39 that you can see this a little more clearly. Yeah let's hope this
46:45 . So here's my P. R. S. Take keep
46:53 We said this is atrial deep Where does atrial re polarization take place
47:00 here. Right. So this should the period of time we're seeing atrial
47:06 contracting, right? Because that would that's that action potential. And so
47:13 contraction is taking place over here. over here this is the ventricle d
47:19 . So what you're doing is you're that action potential. So this is
47:24 period of time when contraction is occurring the ventricles. That makes sense.
47:35 that over there. Now those contractions squeezing the muscle right? That I
47:43 that just tells you contraction muscle You have blood in those those chambers
47:51 ? And so it's gonna do is gonna put pressure on that blood.
47:54 if you have a valve between you the next chamber, if you put
48:00 on that blood it's going to cause valve to open up. So the
48:04 open in response to the pressure gradient either side of that valve. So
48:09 pressure behind the valve is going to the blood forward into the next
48:17 If the pressure in front of the is greater that's going to cause the
48:20 to slam shut and now the blood flow backwards. Notice there's no electrical
48:25 here Right now I'm saying there's no activity. And after the whole you
48:32 thing made me think about a little , of course there is some electrical
48:36 here and I'm not going to go too deeply, but there is muscle
48:40 to the ends of the AV,000 called papillary muscles. And so they're undergoing
48:46 . But they're kind of like trying hold on to a wild horse.
48:50 , as the ventricles are contracting, they're doing is they're contracting as well
48:54 they're basically holding and preventing the valve diverting the wrong direction from all the
48:59 inside the ventricle. All right. notice did I save right, all
49:03 stuff down? No. Is that sitting here on the on the
49:07 You know what I want you to is the pressure is what's opening and
49:13 the valve. All right. the state of what that valve
49:19 is in the open stairs and close will help us understand the stages of
49:23 cardiac cycle. All right. The cycle, we have the atria and
49:29 . We can separate them out independently each one goes through a period of
49:33 and relaxation. The atria contracts. ? We see it up there and
49:38 it goes through and relaxes. The contracts and then it goes through and
49:42 relaxes. So, there is both sisterly and a diastolic in both.
49:47 atrium and the ventricle. That's what terms mean Sicily is a period of
49:51 and the period of time where that is impotent emptying its materials. All
49:58 . It's also the period of spread excitation for diastolic. That's a period
50:02 relaxation. That's when the muscles Finally I get to kick back and
50:07 for a second. That's the period the chamber is gonna be filling up
50:11 blood. So what you're going to is going to fill up with blood
50:14 the relaxing phase and then you're going contract and push the blood forward during
50:18 contraction phase. Then you go back relax, receive the blood squeeze in
50:23 contraction phase or the sisterly. So , diastolic systolic diastolic. All
50:28 So each of them both the age the ventricles each have this this this
50:34 of cycling. But what we do we typically focus only on the
50:41 Why? Because it's easier. All . So when you hear the word
50:45 or diastolic automatically think ventricular Sicilian ventricular . If it's prefaced with atrial systolic
50:53 diastolic now you're talking about the All right. So it's just kind
50:58 it's like saying the dollar when you dollar, What do you think of
51:02 of american money, don't you? there other countries that use the
51:06 Yes. But then if you're going talk about the Canadian dollar, you're
51:10 say Canadian dollar. If you're gonna the Australian dollar, you're gonna say
51:13 dollar when you hear dollar, it's dollar. All right now, Depending
51:22 what your book use, fortunately, book goes minimalist as thick as it
51:28 . There are many cycles or many of this cardiac cycle. Our book
51:32 four. And I think in doing , it makes it easier to understand
51:36 . All right. What we have we have an inflow phase. The
51:41 phase refers to the period of time the inlet valve allows materials to flow
51:46 whatever's on the other side of that into that chamber. All right.
51:51 so the valve on the other side that chamber is going to be
51:55 So, if you're thinking about the , alright, I'm just gonna draw
51:58 chamber like this for the ventricle. would have at the inlet valve,
52:02 have an A. V valve, your ventricle and on the other side
52:05 have your simulator valve. Right? , what it's saying is in this
52:10 example, if we're talking about Sicilian asleep, which is when I say
52:15 term I'm using, usually referring to ventricle, Right? I'd say the
52:21 V valve is open, allowing materials flow in, but this is
52:25 The materials can't flow out. That be the inflow stage. All
52:30 then, have a period of time both these valves are closed. So
52:35 is moving in or out. what we'd say is that we have
52:38 isil volumetric period. Now, what's during this volumetric period? We're going
52:44 a contraction. All right. So fluid is not changing. But the
52:50 is going through a contraction. And as the pressure inside that contraction or
52:54 tension that contraction builds up, it's to create enough pressure to open the
53:02 so that the blood flows out. right. That would be the outflow
53:06 and then the last phase then would okay. The pressure on the other
53:12 is greater than the pressure on the . So this causes this vow to
53:16 . And so we're now in an volumetric relaxation phase. So, we're
53:20 to go here. Inflow. Isil contraction. Outflow. Isil volumetric relaxation
53:27 , repeat. Yeah. Always in US country, it's just portion of
53:37 time intervals are squeezing, right? . That's enough pressure, bingo.
53:47 decision. Because that's just back to that the school doesn't finger.
53:55 You know, you're right bingo. what Yeah. And here and that's
54:01 his name is. I'm sorry. , you're absolutely right. You've summed
54:04 up probably as easy as I could . You know. It's basically
54:08 look, all we're gonna do is going to ask question where the pressure
54:12 . Right. So, there's some of pressure over here. That's greater
54:15 the pressure in there. That's driving fluid in and then the ventricle ventricular
54:21 because we're looking at a ventricle ventricular contracts. Which creates pressure. That's
54:25 than over here. So it's going shut that one but it's not big
54:28 yet to open this one. And the pressure gets big enough it opens
54:31 one so fluid flows out. And when that muscle goes through relaxation,
54:38 the pressure over here becomes so big it causes that valve to shut and
54:42 fluid moves in around. And then the pressure over here becomes bigger than
54:46 then we're back up here again and just repeat that now you can do
54:50 for the ventral, you can do for the atrial. But if we
54:52 it for the atria gets kind of and so we just focus on the
54:55 were there and then there. Yeah. I think it's about 70
55:04 is left over the whole the whole , whatever the stroke volume happens to
55:10 . Yeah. Yeah. So but always going up with like a little
55:13 about 70 miles. So it's not completely emptied. It's kind of like
55:18 know when you drink a soda and get down there and you can hear
55:22 here there's fluid in the bottom. . Listen it's the back pressure,
55:35 ? So as I squeeze the back wants the blood, the blood wants
55:39 go backwards but the valve in response that pressure slam shut. So remember
55:45 movement of the valves is dependent upon . So it depends on which side
55:49 pressure is the greatest. That's the thing to take away from all this
55:52 that wherever the pressure's greatest it's going cause that valve to open or
55:56 So we just need to know where pressure is. All right. I'm
56:01 to see why these two things are . Oh I'm just trying to show
56:05 here, not only to your So this is basically the same
56:08 It just shows you where those phases and what shows you where ventricular systolic
56:13 diastolic are taking place relative to those . Yeah true. Yes.
56:25 Well there's so so technically speaking you're going to get back flow All
56:30 And I'm gonna hopefully answer that question in just a minute. I'm watching
56:34 . So I know how much time have. All right. So then
56:37 come up to the wingers diagram and you look at this you kind of
56:43 but this is everything you want to about the heart but were afraid to
56:46 type of diagram. All right. I'm just gonna break it down up
56:49 at the top. You can see G. Right so you can see
56:52 P. Q. R. T. Rinse repeat in the middle
56:56 . We're looking at pressure both in atrium of integral and we're going to
57:00 how they're working relative to each other we're seeing the heart sounds and here
57:05 looking at volume of blood here in left ventricle. We tend to focus
57:10 the left hand side because systemic Easy to think about. All
57:14 The same thing's happening on the right as well. All right. And
57:19 down here, at the bottom just showing you where you are relative
57:23 uh systolic and diastolic. And then here just pictures to match.
57:29 so, that's that's really what the does and why it's such a powerful
57:35 , because it basically puts everything up for you to look at individually think
57:39 what's going on at this particular time this particular stage. All right.
57:44 , the first stage is diced All right. In diastolic Asus.
57:50 would be mid and tricolor diastolic. right. So, diastolic tells you
57:54 is the muscle doing. It's All right. So, it's basically
57:59 a relaxed state. So, the if it's in a relaxed state,
58:03 means that the pressure inside the ventricle going to be very, very
58:09 But you can see here what we're to do, and this is really
58:13 of you can see it's actually kind growing over time now, what's going
58:21 . All right? The valve is to be open, right? Because
58:26 pressure in here is low. So is flowing from the atrium and the
58:31 as blood flows in from the hatred the ventricle as more blood goes in
58:35 . What's going to happen to the ? It's going to go up and
58:38 going to go up slowly, It's like filling up a bag or
58:42 up a balloon as you fill up balloon as water goes in. The
58:45 gets greater and so the balloons kind expands right in response to that.
58:48 the balloon expansion is basically the pressure it to expand, ventricles not
58:54 All right. I'm just using as example. All right now, the
58:58 on the other side over here is than the pressure inside so that valve
59:02 closed. So notice what phase we're . We're in the inflow phase.
59:07 , it's very slow. It's due venus inflow. The atrium is not
59:12 through a contraction at all. So we're saying here is that the the
59:16 pressure in the venus side of the ? Remember? It's a circle,
59:21 though that's not where all the blood are. But we basically say over
59:24 and the vena cava is greater than the atria and the pressure in the
59:27 is greater than the ventricles. So lowest point of pressure between those three
59:31 of the ventricle, so blood flows the Vienna cable to the atria to
59:34 ventricle without stopping. Remember how I it as. It's like the blood
59:38 like on a tour and it's oh this is a nice room?
59:41 , that's kinda cool. I'm going just keep going over here because this
59:43 the direction of flow. All now the pressure is rising. That's
59:49 pressure I just showed you and the volume is rising. So you can
59:53 here and you can see there's that . All right. Do you see
59:57 the rise is slowing down over That makes sense to you. Why
60:03 as I'm filling it up more and , it gets harder and hard to
60:05 things in there. Right, So kind of what's going on. That's
60:09 . That's the very first stage. , what we're going to do at
60:14 P wave? Right? That is signal to cause atrial contraction. And
60:22 what's going to happen is is as muscle contracts. What it's gonna do
60:26 it's going to create a pressure right? It's squeezing on whatever little
60:31 in the atria and it's squeezing it into the ventricles. So you're gonna
60:35 this slight bump in the atrial That's that blue line. Right?
60:40 as I push that blood into the , right? So that small little
60:45 up, what happens to the pressure the ventricle? You get a slight
60:48 bump. All right, That kind makes sense. If I squeeze
60:52 it's gonna push it over there and pressure is gonna rise equally. All
60:57 , But notice a v valves still . Uh the semi lunar valve is
61:02 closed. Right? So what we is we're still in the in flow
61:08 . Now at Q. Right we're going to see the HR
61:14 begins to re polarized. So that is relaxing and now the ventricular muscle
61:21 going to start contracting. That's what QRS represents, right? That's the
61:27 deep polarization. So what's going to now is I'm going to start contracting
61:31 muscle and look at what happens to pressure boom. It starts shooting
61:37 right? So basically, I'm here to hear when the pressure on the
61:42 goes really, really hard. I the A. V valve closed.
61:47 how do I know because it makes noise love. All right now,
61:55 got a container full of fluid that's compressible and I'm squeezing on the
62:01 What's happening to the pressure inside? going to build up. They
62:07 anyone here, Oh, you have water bottle. How full is your
62:09 bottle? No, I'm looking at one right over here. It's all
62:13 . I want you to do something I want you to squeeze it as
62:14 as you can make it explode, , squeeze, squeeze the water coming
62:20 . Why not enough force? You're strong enough. Keep trying eventually.
62:28 gonna be a point as she squeezes that waterfall. There's a weak point
62:31 that bottle. What's that weak The top? So the top is
62:35 blow if you put enough pressure. what we're doing now is we're in
62:39 middle of that contraction period where she's on this side of that ventricle that's
62:44 interval. And you're squeezing as hard can you're building up pressure, building
62:48 pressure, building up pressure. And going to get to the point where
62:50 pressure on the inside becomes greater than pressure on the outside. And that
62:54 where that outside is is here at semi lunar valve in this case would
63:00 the aortic valve. All right. that's what you're seeing. That rapid
63:05 . But both valves are closed. we're in the ice of volumetric
63:09 I'll phase right? There's no changes the ventricular volume. There's no flow
63:14 fluid. But then you get to point where the pressure inside that ventricle
63:23 becomes greater than the pressure inside the . So that's sinning lunar valve
63:28 Open blood now flows rapidly out because nothing resisting the contraction. The pressure
63:37 shooting through the roof. That's why keep shooting past it. That's why
63:41 see that rise. Okay? But at what's happening to the flow of
63:47 mm blood in the ventricles. He's . It's going into the aorta.
63:53 you're dropping down now the pressure or amount of blood during that isil volumetric
63:59 period. That's at the end of , right? We started our squeezing
64:02 . So we call that the end volume at the end of Sicily we're
64:07 to have blood left over. That's in systolic. And the difference between
64:12 are stroke volume really should stay from to there. That would be our
64:16 file. So we can mathematically calculate out. You need to we don't
64:21 to we just need to know what relationship is. All right. But
64:25 blood is flowing out and there's a decrease and notice it slows down.
64:30 reason is because the more fluid leaves kind of fluid leaves on the front
64:34 of something kind of trickles out at back end. What we're doing is
64:38 squeezing, squeezing, squeezing. Notice the aortic pressure is doing, is
64:41 matching ventricular pressure? But notice it underneath it. If the art pressure
64:48 above the ventricular pressure, blood's gonna to go backwards. So during this
64:53 of time aortic pressure is rising as , but it's always sitting just beneath
64:57 ventricular pressure, Right? Because what have that look on your face like
65:02 away. So, just remember Okay, remember fluid is going to
65:06 down the path of least resistance wherever pressure gradient leads it. So if
65:10 pressure is higher than the other, the direction of flow. So if
65:14 pressure inside the ventricles greater than the , it's going to go to the
65:17 . But if the pressure inside the is greater than the vehicle you're going
65:20 go backwards, which is not That's when the valve shirts. And
65:26 would be the next step. All . So in that late period that
65:32 ventricular sisterly. That's when the pressure to fall, muscle begins to
65:36 All right. But the aorta has all that blood. It hasn't just
65:40 it on its way and now it's to push blood in all these different
65:45 . The pressure has risen and as pressure begins to drop in the ventricle
65:48 pressure in the aorta stays high and a point where they swap positions and
65:54 the aortic pressure becomes greater than ventricular then what's gonna happen is blood tries
65:58 flow backwards. And that's when the lunar valve slam shut. All right
66:04 the A. V. About is closed and the reason it's closed is
66:08 can come down here and look and can see the pressure right in the
66:14 is much much higher than the pressure the um atrium. That isn't going
66:19 open until when it's all about pressure . If the ventricular pressure is greater
66:29 the atrial pressure and the valve is . When does the valve open?
66:36 the opposite is true when the atrial is greater than ventricular pressure. So
66:40 ain't happening yet because our muscles still ventricular muscles still contracted. All
66:45 So what we're doing is now we transitioning from here to here is what
66:50 trying to get at the valve is , blood is left. But now
66:55 so much pressure over here that we're to start seeing backflow. But that
66:59 V valve is still closed. That of blood when that thing closes is
67:06 to be the end systolic pressure. I throw this up here just to
67:11 of help you visualize this. it's about 50 miles of blood.
67:17 , I was wrong. About 70 . All right. So, you
67:20 pushed about 100 and 20 mils per . So, basically stroke volume is
67:24 the difference between the end diastolic volume the in systolic volumes. There is
67:28 math. So, the ejection you can actually calculate that out.
67:33 should succeed. About 55%. All . So, there's there's some math
67:38 this. But I'm not going to there and make you do any.
67:41 understand healthy people have a stroke That's or sorry, ejection fraction.
67:47 50% of the stroke volume. I that right. Of the sorry,
67:55 volume. Mhm. Back to our thing. Our last little little part
68:01 the play. This metric relaxation So, our heart is now going
68:08 a ventricle is now going through The aortic pressure is high then.
68:14 the ventricular pressure begins to drop as muscles relaxing when it drops below the
68:20 pressure. That's when the valve There's a semi lunar valve slamming
68:26 Think about your heartbeat. Come You've all laid your head on somebody
68:30 listen to their heartbeat. Loved loved up. Loved up, loved
68:37 . And what you're doing is you're between that A v valve closing semi
68:41 valve closing a valve closing. do you hear the valve opening when
68:46 come through doors? They don't make , It's they make noise in the
68:51 . They don't make noise by closing the door. It's when they
68:55 they do when they close the door it. Okay, terrible analogy.
69:00 I like it fine. All So at this point now, the
69:06 in the atria is still not high to get the valve open. The
69:11 of the aorta is greater than the inside the ventricles. So the semi
69:15 valve closes. So now we're in place where we have this volume of
69:19 that in systolic volume. All And that's what's left over and it's
69:25 going to open. That valve is going to open again until that muscle
69:29 relaxes. So, we're still in diastolic as we drop down in the
69:36 stages and then the last little bit , is that rapid ventricular filling.
69:42 , we're not looking at on this . We don't see the atrial
69:47 but you can kind of guess based what you see here, what's the
69:51 doing as it comes into the Is it flowing in. Is it
69:56 ? Yeah. To look at the . A point when all that fluid
70:00 kind of collected, right, then of a sudden that valve opens up
70:04 it's just like rush into the it goes, pressure drops. This
70:09 is still dropping, just a function of relaxation. But as the fluid
70:14 comes around from the veins to I mean, to the atria,
70:18 just gonna keep flowing through that opened V. Valve and then it
70:26 you see, and then we're back we started. Yeah. Mhm.
70:37 , it's the ap valve followed by semi lunar valve. Yeah, just
70:44 . Yeah. Angry teenagers. You tell me what to do.
70:53 Now this flow and this period is beneficial to increasing and decreasing heart
71:01 In other words, we are going fill up the majority of the ventricle
71:05 the front end because of the fluid in the atrium and waiting for the
71:09 . V. Valve to open. right, And then what's going to
71:13 is is that there's little filling that at the very end and only when
71:19 squeeze. Do we get that last bit? So, what I want
71:23 to think about is as the heart increases, we're not having to do
71:29 to the volume. Volume is more less staying constant because most of the
71:34 occurs over here. You see that the two curves. So The Red
71:38 represents the heart beating slowly. The represents the heart beating faster. And
71:43 for both of them. The rate which we're filling is more or less
71:48 . But look here when when we a fast heartbeat, that's when we
71:52 that little squeeze and push the less of blood. But when we're having
71:56 slow heartbeat, look out a little is actually being filled in. It's
72:00 like my thumb height, right? wise? That's like what a couple
72:07 based on this. If that's 70 , it's like just a couple
72:13 So, by having by basically looking the physics, you can actually see
72:20 heart deals with same volume almost all time. It doesn't have to worry
72:25 increasing or decreasing volume because heart range changing now. It will we're going
72:30 see that. Probably not today, we will see that. All
72:36 Doesn't affect the volume. Heart love and dub. Don't worry about
72:42 other ones. All right. There's uh I mean, the closing of
72:47 A. V valve. Closing of simulator valve. I put this up
72:50 to show you that. Yes, are other sounds but we don't
72:55
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