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BIOL 2302 Human Anatomy & Physiology II - 2302_lecture05_0131
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00:01 Good. There we go. Good campers. How are we doing
00:06 Aren't we? Glad we're not living Dallas where it's actually colder than this
00:13 freezing. Um All right. So , what we're gonna do is we're
00:18 to continue our discussion about the heart probably in the reading, you saw
00:22 horrible graph, right? It was big massive graph and it had like
00:27 the E. K. G. it or the E. C.
00:29 . On it. It had pressure volume and heartbeat. And uh did
00:33 see that that graph show up? you guys like look at it?
00:36 not gonna learn this and just kind skipped on. Yeah. Uh if
00:40 learn that you've learned everything you need know about the heart but were afraid
00:43 ask. So we're going to cover today. Um as part of our
00:47 and we're going to stop being afraid graphs. Because graphs are awesome.
00:52 tell us everything we need to know it makes life a lot easier for
00:56 . But before we do that, we're gonna do is we're gonna start
00:59 understanding what's going on with regard to electrical activity. We started or we
01:04 on thursday today is Tuesday. Okay. I don't never know what
01:11 it is. All right. On . We talked about these action
01:16 Right? And these action potentials are electrical initiators of the contraction, lack
01:22 a better term. So we had two different types of action potential.
01:26 had action potential that was for the rhythmic cell and that is what serves
01:31 the electrical signal to activate the action in the contract. I'll sell and
01:36 the contract. I'll sell that contract make the heart go thump thump.
01:39 , Well, good with that. right. So, what we're gonna
01:42 now is we're going to take that example because when we talk about an
01:45 potential, we're really talking about what's on inside one little cell and your
01:50 isn't one little cell. It's how cells? The answer is lots.
01:55 . And so, what we are is we're now looking at the heart
01:58 a whole. And what we're gonna is we're going to see that there's
02:02 conduction system, basically a bunch of wiring. All right now, it's
02:07 electrical wiring. 1 2. This not a nerve system. This is
02:12 muscular conduction system. Alright, whenever you look at any sort of
02:17 textbook, you're gonna see three different . We've talked about red and
02:21 right? Red is oxygenated blood. represents deoxygenated blood, except in certain
02:26 when the author gets all funky and , but usually you'll see a third
02:30 , which is yellow and yellow usually nerves. And so when we talk
02:34 the conduction system, they draw yellow throw this to talk about this conduction
02:40 . It is not nerves. All . These are the auto rhythmic cells
02:46 to each other, creating this network looks kind of like a nervous
02:51 And it's not all right. And we're seeing in this particular picture is
02:55 four basic areas that are part of conduction system. Alright. The first
03:01 called this, the sino atrial Then we have the atrial ventricular
03:08 And then we have the bundle of named after the guy that discovered
03:12 And then finally we have the per fibers. And those are the four
03:16 that serve as this conduction system. so what we're going to see in
03:20 rhythmic cells using this as a way tell each other it's time to
03:25 And then that when that's electrical passes all the terrific cells and they're passed
03:30 to the contract. I'll cells that up the rest of the heart.
03:33 can see in the picture what the of the heart looks like.
03:36 So the essay notes, these are specialized region found in the upper right
03:43 wall. Alright. And what we're to see here is that's there and
03:48 connected to the next one in The A. V. Node.
03:51 A. V. Note or atrial node is located at the cross.
03:56 when remember we drew the heart? our artistic endeavor how perfect and beautiful
04:00 heart was right where that cross where it separates the two hr from
04:04 two ventricles that septum. Remember we service between the atria and ventricles as
04:10 dividing line to prevent the electrical activity the atria to affect the electrical
04:15 The ventricles. The A. Note sits at that juncture so that
04:19 electrical activity of the atria can pass and down to the ventricles. So
04:25 the only point of of electrical conduction the two areas and then down through
04:31 middle of the ventricular septa. That where you're gonna see the bundle of
04:35 . And it actually divides into two . Because what we're gonna do is
04:39 gonna work our way down to the . And then we divide into a
04:42 bunch of bundles that then spread around outside walls of the ventricles. And
04:47 last little bit are the perkin gee . Right? So S. A
04:52 , a B node bundle of and then on the edges per kenji
04:56 . That's the anatomy of this. right. So if you remember that
05:00 , you're probably in good shape. right. So of all these the
05:05 important in terms of governing the electrical through the heart is the S.
05:10 . Node. Now each of these . Remember our auto rhythmic cells.
05:15 it doesn't matter if you look at A. V. Note, kenji
05:18 is a bundle of hiss or the . A note. I notice how
05:20 put them all out of order. each contain auto rhythmic cells and auto
05:25 cells naturally D polarized, going you down to that bottom and slowly d
05:32 de polarizing faster, Get to that and come right back down and just
05:37 . So they are a natural pacemaker . But of all of these four
05:43 , it's the S. A node governs the rate of electrical conduction through
05:48 system. Alright, So each of have their own rate. And the
05:53 that most books kind of explain is think of a train, a big
05:56 train. And the big long train engines at the front of the train
06:00 engines all work together to pull the train. But if the first engine
06:05 , you still have three other engines pull the train. And so each
06:09 can do the job of the A. Node. But because the
06:11 notes on the front end, it's for governing at all. That kind
06:15 makes sense, sort of terrible illusion it doesn't explain some of the weird
06:22 that are going on the heart. that's the idea. All right.
06:26 the idea is if you somehow damage S. A. Node,
06:30 don't worry, you still have other , I'll cells that are responsible for
06:37 the heart rate and the heartbeat. ? And so the next one in
06:42 would take over. All right. if the S. A note fires
06:47 signal is then gonna be conducted down the A. V. Node which
06:50 fires which conducts it down to the of his which fires which conducts through
06:55 park in the fires which all fire the path or the pattern that we're
06:59 to see. So what is actually on? All right. So we
07:06 to follow this path from the A note down through these structures.
07:10 the first thing we're going to see the S. A. Node fires
07:13 those auto rhythmic cells are going to and send their signals in two different
07:19 . The first direction is going to across from the right atrium over to
07:24 left atrium and this is referred to the inter atrial pathway. And what
07:29 trying to do is we're going to to excite all those contract I'll cells
07:33 make up the two atrium because we them to contract at the same time
07:38 we said is we have a heart is a two pump system. So
07:42 want to pump blood from both a into both ventricles at the same
07:47 And so the activation of the A. Node ensures that this occurs
07:51 both will go thump at the same . So far. So good,
07:55 easy. Alright now, following atrial , we would like the ventricles to
08:01 and so we want our signal to from the atria to the ventricles.
08:05 so the second pathway is the inter pathway and hear the signal is going
08:10 the S. A node down to the the note is located, hence
08:15 name or inter nodal. So what doing is we're setting it up so
08:19 the both atria contract first inter atrial . And then we're sending a signal
08:24 that we can set up and get ventricular pathway or the ventricular muscle to
08:29 ready to contract. And that's what picture is trying to show you.
08:34 I've kind of put arrows here, of represent that we're going in this
08:37 to help this one contract with And we're moving the signal down to
08:40 A. V. Note which is in that septum so that we can
08:43 the signal further onward. So that in the international pathway gets down to
08:52 A. V. Node. Now the A V. Node responds a
08:57 slowly. Alright, It's what's referred as the A V nodal delay.
09:02 , what we're doing here is we're that the atria contract. We don't
09:07 the atria to contract and be in middle of contraction to start the ventricular
09:11 because now you're creating a path of instead of a path of reception.
09:18 kind of makes sense. In other , if there's pressure that's opposing the
09:23 of blood into the ventricle then you're gonna move blood into the ventricle and
09:28 a bad thing. All right. the idea here is the A.
09:31 . Note. The A. Node basically receives its signal and twiddled
09:35 thumbs for a second, right? it kind of sits there and
09:38 alright, I'm gonna wait for the to begin its contraction before I send
09:45 signal down to the next structure which be the bundle of his.
09:50 And so this allows for the complete polarization. So all the cells of
09:54 atria receive their signal and then they to contract. And that allows for
09:59 contraction occurs. So that blood which be in the atrial be pushed into
10:03 ventricle. And then that signal is go to the ventricles. So from
10:10 A. V. Node and there's lot of words up here. But
10:12 worry about that. Now, what can see is that we go from
10:16 A. V. Node right down bundle of hiss and there's nothing slowing
10:19 down now, it's just basically gets to the apex and those fibers spread
10:23 becomes the fibers and then the signals up and around the edges of the
10:28 muscle. All right now, what doing here is we're basically spreading an
10:33 signal as fast as we can to many cells as we can.
10:37 Because you remember there are more cells the ventricle than there are in the
10:42 in terms of muscle cells. And so we want to get that
10:46 as fast as we can because we so many more cells to talk to
10:50 we want to ensure that they're all communicated with almost simultaneously so that they
10:54 contract simultaneously. One the two ventricles . But we want to ensure that
11:00 actually get a really strong contraction because want to propel blood out of the
11:04 either to the system or up to lungs. All right now the the
11:09 are a bit more organized than what see in the inter atrial pathway or
11:15 the international pathway. It's they're basically bunch of of not contract I'll cells
11:21 the auto rhythmic cells and they're all to each other in rows. So
11:25 be like me passing going here, do this and then you take another
11:29 over here and passing over here and it starts passing to everybody. And
11:33 if you can imagine only 1% of cells being ought arrhythmic and the other
11:37 are contract. I'll eventually, everyone's get it. But if you spread
11:42 those pathways through everybody, then the is going to get out a lot
11:47 . That kind of makes sense. that's what's going on with the fibers
11:52 the bundle of his. So let's it down quickly and then the let's
11:55 it out to as many cells as possibly can. And those auto rhythmic
11:59 get that signal they send it off then the contract cells start receiving the
12:03 and then when they receive that signal produce their actual potential. Which is
12:07 cause both ventricular muscles, both in left and the right. To contract
12:12 same time so that they can push blood out. Alright. So I
12:16 a lot of words to explain That was pretty simple. All
12:20 So in terms of electrical activity, rhythmic cells are this pathway. S
12:26 note to a V. Node, ? S a note over to the
12:30 atrium so that both atria contract a nodal delay waiting for the signal to
12:36 a contraction down the bundle of his through the fibers. Then the ventricles
12:42 . Alright, pretty straightforward. I believe I spent that much time talking
12:47 it. All right now you're probably familiar when we talk about electrical activity
12:54 this picture. If you've watched enough of tv shows you've seen the machine
13:00 goes peeing. All right. That's what monty python referred to it
13:04 the machine that goes ping beep, , beep beep beep beep. Somebody
13:08 there with an intubation tube in their . All these doctors with worried faces
13:13 them saying horrible things and then beep in the background. And you see
13:17 little dude. Alright. For those you who are planning on this
13:23 you will never see a picture as as what you see in the
13:27 All right. What you're looking at is the E. C.
13:30 Alright. It stands for electro Alright. And what this is is
13:36 recording of the electrical activity of all muscle cells in the body. Or
13:42 the body, But in the heart now it's a representation, it's not
13:47 actual direct recording. Um This picture do an incredibly good job of showing
13:53 where the leads are. So what do is they will put leads on
13:56 two wrists, one on one of legs and they put like six leads
13:59 around the heart. And it's kind like what you would do is if
14:04 guys we all watch the football even if you weren't interested. Have
14:07 watched a football game? Yeah. you noticed like in a football game
14:12 you have multiple angles on the When it happens? Like for
14:16 if there's a controversial play, you , they stop and they go to
14:21 and then the announcers make all sorts inane comments because they're experts, you
14:25 ? And then they show you a from this side and they show you
14:28 view from that side. They show a view from this side. View
14:30 this side And people up in new are usually and they're watching up in
14:35 york are they are they really watching new york? Or is it just
14:38 randomly saying stuff? I don't But the idea is they're all watching
14:42 play from a different angle and you make or break a play based on
14:49 view, right? And so it's those views create the composite image of
14:54 going on. And if you watch long enough, have you seen how
14:57 now have these digital plays? Like it's like this is what they
15:02 They show this it's like watching a game where they like circle the person
15:05 they yeah so that's a result of composite video that they actually create and
15:10 can actually create what play looks Now why do I go through this
15:14 ? Because I like football and I to make you guys like it too
15:17 though it's not going to necessarily be . But number two is because this
15:22 what an E. C. Is like. Alright when I'm looking
15:27 this, what we're doing is we're two leads and we're using those two
15:31 as a positive and negative and we're at the activity between those two
15:36 And so the view from Point To Point B. Is gonna be
15:40 from the view from Point A. point C. Which is different from
15:43 view from the point B. To C. Which is different from the
15:46 of Point B. To point And yada yada yada yada yada.
15:50 so each of the views that you're see gives a different idea of what's
15:55 on with with regard to the electrical of the heart and then if you
15:58 all of that together and composite The machine puts out a picture that
16:04 like that thing that you see here the bottom. These little wave
16:08 And so, what this is is representation of the electrical activity, not
16:13 actual measurements of the electrical activity. . It's not a measurement of a
16:19 action potential either. All right. we're looking at is all the activity
16:24 the heart at the same time over . What's going on? Alright,
16:30 , I have a bunch of things , just so I make sure it
16:32 you the recording of the electrical activity you measure in the bodily fluids.
16:37 , it's in direct to its overall of the activity. So, what
16:41 seeing is you're seeing not the actual polarization and polarization. You're looking at
16:46 is the heart doing during this period time? And what does it
16:49 What does it kinda look like? right. So, you're not looking
16:52 the action potential and what you're doing you're seeing changes in voltage. All
16:57 . But you're not watching deep polarization re polarization. Alright, So,
17:03 gives you or gives the physician or is looking at this and comprehensive assessment
17:09 the electrical changes that are taking And so, it has parts to
17:14 . All right. We have three distinct wave forms. And this is
17:18 kind of the fun part, I . You know there's stupid little facts
17:21 this thing. Alright so you'll see the first wave begins with P.
17:24 have any idea why it begins with . You don't want to take a
17:30 . It's my favorite little story. my favorite but it's up there.
17:36 . In biology we always name things alpha or a. Or one or
17:42 roman numeral. So the yahoo who working on this stuff said you know
17:47 ? I'm tired of starting things with letter A. Or alpha or
17:51 I'm gonna begin in the middle of alphabet. I'm gonna pick the letter
17:55 . And I'm just gonna see how waves are formed. And so he
17:58 pee and he saw the next one was Q. And then he saw
18:02 and then he saw S. And he saw T. And then it
18:04 repeating itself. And so that's how got P. Q. R.
18:07 . T. It has no. it's funny I think right. I
18:13 scientists are always so stiff and Gotta know now stupid things fly.
18:21 are awesome. They name all their after jeans. What genes? All
18:30 so three distinct wave forms first one they all correlate with something that's going
18:35 in the heart. First one is P. Wave. And what it
18:38 is atrial de polarization. In other the contraction that you're gonna see as
18:44 result of all those cells. Polarizing is where you're gonna see the
18:48 . Wave. The Q. S. C. Goes down first
18:51 up and then comes back down That's referred to as the QRS
18:55 So it's Q. There's a Wave. There's an art wave.
18:57 an S. Wave. It represents deep polarization. So we have
19:02 L. D. Polarization that would represent the contraction ventricular re polarization that
19:07 ventricular contraction. And then the Wave represents ventricular re polarization. What's
19:16 atrial re polarization? Thank you for attention and playing my game. It's
19:21 hard. Very early in the morning do so. So why is it
19:26 ? Does the heart does the atrium re polarize? Well it's there it
19:37 actually there. You just can't see . But that's a good guess.
19:41 like oh isn't just relaxing? Well what report Ization represents. It represents
19:45 relaxation of the heart muscle. All . I'm gonna tell you why this
19:49 is getting harder and harder every year I've got if you don't know I
19:52 two sets of twins which is always to tell people because they always kind
19:56 freak out. All right. I three boys out of those two sets
19:59 twins. Alright so all my boys like me. I'm basically I've cloned
20:07 and you guys are all in trouble we're taking over the world. All
20:10 now it was a lot better when were small and cute. But now
20:14 all in junior high and higher so not quite as cute anymore.
20:20 They're not little kid cute. That's it that way. All right.
20:24 youngest of all my boys. So second twin of the second couple,
20:29 mean, he's spot on, looks me at that age, right?
20:34 he's also a little bit shy. so when he was like five and
20:38 years old, if I had brought into this classroom, he would have
20:41 out here at all of y'all and would have been like and he would
20:44 just run right behind me. And then there's nothing I could do
20:48 like, you know, show if turned like this, he would just
20:50 behind me all the time. Well, that's what atrial re polarization
20:56 done. All right. It's in . You just can't see it because
21:00 have this Q. R. Wave which is massive. And so
21:04 re polarization sits at the exact same . It's just masked. Sorry,
21:10 should do it that way. It's by that massive Q. R.
21:12 . Wave. All right. you can see that we have eight
21:17 old deep polarization somewhere around where QRS . That's where you'd see atrial re
21:23 but you can't see it. You ventricular deep polarization through the Q.
21:27 . S. And then over here you see that t. I should
21:30 it the other way T. Represents deep polarization or re polarization. All
21:36 . So what these are supposed to you is the activity that's going on
21:42 that heart. All right now remember is not specifically referring to action
21:49 Alright. So you can't see the note actually firing right? That that
21:56 potential that's a result that creates this of electrical activity is not observable.
22:01 you see is you see all the that make up the atria coming together
22:08 contracting or race basically the electrical activity over the muscle cells that are going
22:13 result in the contraction that are gonna place and cause the contraction of the
22:18 . Right? So that's what you're seeing here is you're seeing not only
22:22 a note, but you're seeing all contract I'll cells. And the current
22:25 trial cells really are what are represented there. All right now, notice
22:30 not very big relative to the And the reason for that again,
22:33 to do with the volume of muscle the concentration of muscle. The atria
22:38 have a lot of muscle. They have to do a lot of
22:40 All they've got to do is squeeze the last bit of blood out of
22:44 atria and squeeze it into the And we're gonna see what that means
22:47 in just a moment. Right Not literally filling up and then squeezing
22:52 the blood in the atrium to the , blood literally just kind of passes
22:57 the atrium going, oh this is nice place. I'm heading over to
22:59 ventricle because of the way that these work. All right. So the
23:08 note fires. Um and what you is you see that spread across all
23:13 muscle, that's what that p wave . And then shortly thereafter about 0.1
23:18 after that. That's when the contraction to occur. So this represents the
23:24 of deep polarization and then the contraction going to take place on that.
23:27 have a really good picture that's going show that here in just a
23:31 And if you look at this this if you look down here at the
23:35 , it's just showing you this is it represents. You can see the
23:39 occurring and it's spreading to both So the curious is the trick Euler
23:47 polarization. I said it masks that re polarization. It has this weird
23:53 down thing. And the reason has weird up down thing is because of
23:56 direction that the that the electrical activity to follow. Remember just looking at
24:01 the A. V. Know down the bundle of history of the fibers
24:04 go down and then back up and and each of those fibers are
24:09 And so the down up down activity a result of the direction in which
24:15 that wave of electrical activity flows before get the contraction. And I don't
24:22 if you guys remember but on thursday kind of pointed out this kind of
24:26 act uh kind of spiral shape of heart muscle. Do you remember that
24:31 ? I kind of pointed out and threw it out to the side.
24:34 was like oh yeah you can see how the muscle kind of does this
24:37 eight thing and then I just kind ignored it and kind of went on
24:39 way. Do you guys remember that sort of one person? Okay because
24:44 way that the heart works it actually like so when it contracts and so
24:50 contraction wave is a function of the of that heart muscle and how it
24:55 of creates his ringing action. Now interesting. I have a friend who's
25:00 pharmacist um who has, he was the military and he said oh my
25:08 wave is upside down. What do mean it's upside down? So it's
25:12 down, it doesn't go down up it goes up down and then up
25:18 before it levels out said how does happen? He says it's because my
25:22 when it developed flipped around the other so the muscles are backwards, it
25:28 contracts the right way, right? still rings instead of ringing this way
25:32 rings that way. That makes sense ? And so because of the shape
25:38 his heart muscle it creates a weird . Right? So that's what this
25:42 . Why is because of the weird in which the muscle is arranged in
25:47 heart. And finally you get to T. Wave which I even put
25:54 on the last slide. No, don't. So I don't know why
25:57 didn't put the T. Wave but T. Wave represents that period where
26:00 get the ventricular muscle relaxing again. you've gone through the contraction and so
26:05 you're gonna see relaxation taking place. it's the loss of the electrical
26:11 So if you look at this this kind of interesting. Alright. We
26:17 some areas where there's not gonna be sort of current, any sort of
26:21 activity. Alright. We have this of space. This one showing PQ
26:26 but it's basically from P. To . That's the A. V.
26:29 delay. All right. What's going ? The A. B. No
26:33 . Sitting around waiting right, waiting the signal. Go from the atrium
26:37 the ventricle. I have this long of time from Q. To
26:40 They're calling it the S. There. It is the intervals right
26:44 . So there to there. What's on that represents the period of time
26:48 I'm getting the ventricular contract. I'll in their plateau phase. So remember
26:53 drew the picture we said here we the contract ourselves. They're going along
26:58 rest. They get activated. And they kind of sit there in a
27:02 and then they get go through re . Remember that that that contraction is
27:09 in that deep polarized state allows the to go through a period of
27:15 All right. And you can actually those down. So it's showing you
27:19 , like look here's the contract. cells of the atria. And you're
27:23 P. And that Q. And in the plateau phase. And so
27:29 other thing that sits on top of this, I was like, oh
27:33 not gonna get my pen today, it back in there. So the
27:38 you can look at this is you think about like this this is my
27:47 . Sorry, I'm trying to make nice and smooth. That would be
27:50 contraction of the atria right there. the contraction of the ventricle. Did
27:59 see that soapy initiates the electrical activity goes through the auto rhythmic cells under
28:07 conducting cells. Or the contract. cells contract. I'll cells fire.
28:12 you can see there action potential drawn top of this is not the actual
28:17 itself. It's just saying this is can imagine if you put them all
28:20 this is where that action potential would . And so your contraction made by
28:25 little red here is represented in this right here. And then you get
28:30 a v nodal delay that causes uh the A. V. No
28:34 the signal goes down the bundle of along to the park in the fibers
28:37 activates all the contract ourselves of the . And then the contract ourselves.
28:42 the ventricles are get that ax potential in your plateau phase. The plateau
28:46 represents a period of time where you through a contraction. So the ventricles
28:51 . That's what you're seeing during this of time. And then finally I'm
28:56 gonna look here because we got two them side by side. We have
28:59 space in there and that's the space between when your heart is at
29:05 Okay? The T. P. . Alright, so think about the
29:10 that a heart makes, thump, , rest, thump, thump,
29:17 , thump, thump rest. That is the T. P.
29:24 All right, think about when you're or you see the cute person that
29:28 have a secret crush on. And is your heart? Do the rest
29:33 , rest, rest. The rest what gets smaller right that period of
29:42 here. That is the rest. does the E. C.
29:48 Make sense a little bit as a point. Okay, so this is
29:54 lot of physiology here and I understand an mp class but the idea here
29:58 to introduce you to this idea that have this pump that is going through
30:02 period of contraction relaxation. To push into your uh pulmonary system and blood
30:08 your systemic circulation simultaneously using these two . And the electrical activity of the
30:14 is what allows that to happen. we can measure it by putting all
30:17 leads on your body and looking at movement of that electrical activity which is
30:22 by the CCG. And so if heart is going through a period of
30:26 and relaxation, right, What we do is we can divide your heart
30:30 into these periods of activity and non . Alright. We have names for
30:37 . All right, When the heart in the process of contracting, we
30:41 it sisterly. Alright, if a is going through a period of
30:48 we call it die Estili You all your blood pressure taken at one point
30:53 your life. They give you two , right? What's the normal number
30:57 what's the number you hope for? you wanna know? 1 20/80?
31:02 like please let it be 1 You go in and it's like you're
31:05 , it's like 1 80 over 120 like, oh no, I'm
31:08 No, no, no, that's okay. When you're panicking, your
31:11 pressure is up because of anger Every time I go to the doctor's
31:16 I get angry. So my blood is always up in the doctor's
31:19 They have to take my blood pressure when I'm sitting. I hate wait
31:23 the waiting room sucks right? so I'm always ready to fight people
31:26 the waiting room and then I get there 20 minutes later it's like now
31:29 like okay can we take your blood now? Sure sure. I don't
31:32 now I'm in a better mood But anyway so the obvious thing about
31:36 heart is we're going to go through of contraction and relaxation called systolic and
31:42 . But the thing we don't always about is that remember the atria are
31:46 through a contraction relaxation cycle. So has its own system and die a
31:52 and the ventricles go through a contraction relaxation. So it has its own
31:58 and diastolic. And when you hear terms, if someone says you know
32:02 is the systolic pressure. Usually what referring to is the activity of the
32:08 , right? And they're measuring the in the aorta. Usually really they're
32:12 it way down here and making some . But but the idea here is
32:18 when you hear the word systolic we're usually referring to the ventricles but
32:22 need to understand both chambers have this but typically we're going to focus on
32:30 ventricle. So if you hear system I actually think oh I'm dealing with
32:33 ventricle if we're not dealing with the we will always always 100% preceded with
32:41 alright. But if it's the ventricle lazy and so we just leave it
32:46 , that makes sense. Okay, that mind we've already mentioned heart
32:53 There's two that are very familiar. is what you're most familiar with.
32:56 Love and the duck. That sound and sound to what they refer to
33:00 represent is the closure of the And I believe I mentioned this on
33:04 on thursday last week. So that sound the S. One sound which
33:09 the love. That's the closing of A. V. Valves. Those
33:13 shut and then when blood goes in the ventricles begin contracting, that's when
33:19 valve slams shut because the blood doesn't don't want the blood to go backward
33:22 the atrium. So that slamming is result. I like to think of
33:26 as you can think of it as your blood is an angry teenager and
33:31 you can't tell me what to do and it slams the door shut and
33:34 why you can hear it all And then when the blood is
33:39 the semi lunar valves open and when vehicle begins to relax Then the pressure
33:45 to go backwards into the ventricles and causes a similar balance to slam
33:50 And that's that doesn't sound, that's S- two sound. Now there are
33:54 sounds as well, there's you can a galloping sound which is S.
33:58 and S. Four, we're not to deal with those. Alright,
34:02 I don't have a good example of is primarily but we all can do
34:06 up. Right, loved up is bump bump bump bump. The love
34:11 the dope. All right. All . So, as a clinician in
34:17 future, you can use that to is the heart behaving the way that
34:21 should? All right. Now, flowing through the valves and flowing through
34:30 vessels and flowing through your heart does in what is called a laminar
34:35 and that's what you're seeing in this . Right here. Okay. It
34:39 flows in straight lines. All And when fluid flows like that,
34:47 doesn't make sound alright, It makes when fluid makes sound, it's because
34:53 created turbulence within that flow. So if you live on the first
34:59 apartment, you've probably heard the people flushing toilets, right? You've probably
35:06 showers or whenever they turn on water usually you're not you have old
35:14 I mean, I lived in an complex below somebody and I swear the
35:18 for like 40 years old and you hear everything flowing through those pipes,
35:24 ? Especially toilet. That's gross. can just think all the stuff that's
35:27 the pipes underneath the toilet. And so you hear that? I
35:31 about like when you hear a babbling . Why is the book brook
35:38 Because you have turbulence, right? going over the rocks, that's where
35:42 sound comes from. So this is . So if your blood is making
35:48 and the example of a noise would a murmur if you have a heart
35:52 , what that's representation representing is non flow because of some sort of
36:01 So there's different types of murmurs that can have. So basically it's an
36:06 , Usually these are valve malfunctions. if the valve becomes stiff,
36:12 So in other words, when you open it real well, right?
36:17 when blood flows through you now have resistance and so what's what's blood gonna
36:22 ? It's gonna push through. So like it's like steam being pushed through
36:27 kettle and it whistles. I can't the noise because I don't know like
36:35 . So if you're listening and you kind of a sound, oh that's
36:40 representation that the valves are stiff, not opening properly. So blood has
36:45 wash through in a way to get the other side and the heart has
36:49 work harder. The other is valvular and that's when the valve doesn't close
36:55 . When the valve doesn't close What happens is instead of creating a
37:00 it creates an opening and so now can leak through backwards into the chamber
37:06 it was formerly in. And so you kind of get a swishing noise
37:10 opposed to a whistling noise and then upon where you hear that sound,
37:16 it's a whistler or swish and you it between S. One and
37:20 Two or between S. Two and . One tells you which valve it's
37:24 all right. Yeah. No. because the doctor on a regular
37:34 let's say wait a second. I'm something strange happens. You notice when
37:36 go to the doctor, one of things he does is puts that nasty
37:40 thing on you and says, alright , breathe in deep. They're listening
37:44 tuberculosis right? Because they're looking to how hard is it to bring in
37:48 back and forth. Right? Is something in the lines? But they're
37:51 listening to your heart and whether or there's these weird sounds taking place.
37:55 I think in the previous picture, , it's very easy to overlook
38:02 right? It's like there's a I'll come back to another time.
38:05 look what this picture is showing These little yellow dots are telling you
38:11 the best place to listen to the ? Right? So again, when
38:17 go on to your professional schools and your professional things, this is one
38:21 the professional things they teach you. do you put that colt 1st 1st
38:26 it in the ice and then once dipped it in the ice then you
38:30 it on them and this is the where you put it. All
38:34 so that you can hear best. right? So like I said depending
38:41 when you hear it, and I'm gonna ask you where is the systolic
38:44 thing because this is something that's experiential it's something that you do when you
38:49 off to the professional schools. All . What I want to deal with
38:52 the is the cardiac cycle itself. . We said we go through this
38:57 of contraction and relaxation, both in atria and the ventricles. Alright.
39:02 what we're trying to do is we're to move blood from circulation into the
39:05 and back out to circulation. we'll be going from systemic Into the
39:10 , out to pulmonary or from pulmonary the heart out to systemic.
39:15 And there are at least depending on textbook you look like. There's at
39:19 four cardio stages of the cardiac Your book chose five a book I've
39:24 previously for this class had nine. know it's it's just the author.
39:29 , I'm going to slice the pie and thinner and thinner so I can
39:31 it confusing for you. All So, I think five is
39:35 I think four is the easiest. wish that your book would have done
39:38 , but I'm not gonna teach you your book talks five. Alright.
39:42 what I want to understand here is we're going to look at something that's
39:45 to seem very, very scary and , but I don't want you to
39:49 afraid of it. All right. all we're doing is we're breaking down
39:53 information in the categories so that we look and see what's going on
39:57 What's going on here? What's going here? What's going on here?
40:00 right. So, if you look this this cycle here, I've just
40:02 to look at we have atrial then we have ventricular sisterly. We
40:07 late ventricular system. So, we early and late. So, what
40:09 done is they've taken this and they've into two halves. Then we have
40:13 late ventricular diastolic and then we have ventricular diastolic. So, this whole
40:20 is being broken down around which structure , the ventricle. Alright,
40:27 really what they're saying is, what we're gonna do is instead of
40:30 at the whole heart, we're gonna the heart in half and we're gonna
40:33 at one side. Now. Which are we probably gonna look at?
40:36 typically look at the right side of heart because it's easy to think of
40:40 blood going into the systemic circulation than is to think about going into the
40:43 circulation. Right? So, we focus on the right side and really
40:48 gonna be looking at both chambers. it's really all the focus is let's
40:53 in on what the ventricle is doing that's what we care about is where's
40:57 blood coming from and where is it to? And the ventricle serves as
41:01 pump to push it to. That sense. Alright, are you ready
41:07 the scary graph scary graph? All . This is called the wickers
41:13 I'm not gonna ask you its It's just nice to know what it's
41:17 called because we teach this over and and over again. And if you
41:20 at this you can see we have ? 1234 different things here.
41:26 sometimes you'll have 1/5 thing down at bottom which shows you what's going on
41:29 the heart as well. And what looking at is up at the
41:33 We have the E. C. . Is the BCG scary.
41:37 Okay so we don't have to worry that one. It's just we're lining
41:40 up to the electoral cardio gram. so what we're gonna ask is we're
41:44 ask actually there should be another one here that they don't have. But
41:48 we have in the middle that read purple and blue represent the pressures in
41:54 different places. The red pressure represents pressure inside the aorta. So which
41:59 of the heart are we on the side? Okay. Alright. We're
42:05 at the pressure inside the ventricle. said the right side. I'm so
42:10 my brain is putting what side of heart of my on which side is
42:15 ? My left. Thank you. you guys aren't paying attention. You
42:19 have all just shook your head and you're an idiot? Turn your body
42:24 ? That's yeah. Alright. And you can see over here that we
42:29 the purple is the ventricle and then blue represents the left atrium.
42:34 I gotta get my caffeine going. next step down deals with volume and
42:41 volume of blood inside the ventricle. right. Now, what they're not
42:46 you here is they're not showing you state of the valves. So that's
42:51 you usually will see in the But this one isn't showing. But
42:54 it does show you. It shows the sounds. Where do the sounds
42:58 ? Alright, So that kind of you a hint of of where you're
43:02 because the sounds represent valves closing. ? So that's what you're seeing in
43:07 diagram. Now, the easiest thing do if we have these five stages
43:11 ask these different questions. Alright. are we with regard to the
43:17 C. G. Alright. Where we with regard to pressure? Where
43:22 the pressure? All right. And is a function of volume.
43:28 what is the volume in the ventricle a result of the pressures that we're
43:33 ? All right. What is the of the valve? Is the valve
43:37 or closed? And there's two So there's there's a valve that goes
43:41 the ventricle valve that goes out. we ask the question. What are
43:44 state of the valves in this particular ? So that's going to give us
43:47 sense of which direction is blood flowing is it flowing at all? And
43:51 last thing is um that volume and the last thing. So each of
43:56 slides are gonna have these five things there. Right? It's gonna be
43:59 are we with the E. G. Um What is the chamber
44:04 in terms of of the muscle activity to the E. C.
44:08 So what does that do? The ? What does that do to
44:12 What does that mean with regard to valves? All right. Now,
44:16 do I mean by all this? right. If a muscle contracts it's
44:22 pressure, right pressure drives the movement fluid. Did you guys learn that
44:28 time ago? I hope back in seventh grade when you took the that
44:33 science class. No, you don't that here. Do you guys remember
44:39 word Boyle's law? You may not the law, but do you remember
44:43 the word Boyle's law? Yeah. . It just describes the relationship between
44:47 and volume. All right. If increase the pressure that's gonna drive fluid
44:54 an area of high pressure to an of low pressure. Right?
44:59 Think of a balloon balloon has equal on the inside the balloon as
45:04 But if I take that balloon and blow into the balloon, I am
45:09 a pressure that drives air from my into that balloon and then the pressure
45:15 the balloon begins to increase decrease or the same increase right? Because now
45:22 more volume. And what does that wanna do? Doesn't want to leave
45:25 does it just want to hang out say okay I'm happy to being inside
45:28 bloom. It wants to leave. ? And so you gotta sit there
45:31 clamp onto that little tiny blow area you clamp on it because if you
45:39 and then you have to start all again and now it's wet on the
45:42 and it's even harder. Right? you understand these concepts, We're just
45:48 put names to it all. All ? So our starting point is going
45:53 be in the atrium. Remember we we're gonna look at the E.
45:57 . G. To figure out where going. And so here we
46:00 And we're pointing in our little picture here during atrial Sicily Sicily means
46:08 So if my a tree is what have I done with regard to
46:12 pressure inside the atria has gone So let's take a look at the
46:17 and see what's going on here. here I am. Red arrow tells
46:23 where we are. I'm here at P. R. Interval right?
46:27 sitting in there. So if I down here remember I said atrial
46:31 what is it doing? It's So what's happening is that the patriots
46:37 , right? And it's creating pressure drive blood from the atria into the
46:42 . Now, the only way that happen is if the valve is open
46:47 right. And to the pressure inside ventricle has to be less than the
46:53 . Does that make sense? If water can only go downhill,
46:58 , fluid can only move from an of high pressure to an area of
47:01 pressure. So if I have pressure inside the atrium, right, that
47:09 in order to drive blood out has be greater than the pressure to where
47:13 blood is going. And that would in the ventricle. And if you
47:16 at that graph, is that true that point? So here's the blue
47:21 represents atrial pressure. Purple represents ventricular which is on top of which atrial
47:30 is greater than than ventricular pressure. is on top of purple and notice
47:34 always on top of purple as we're along here. So blood should always
47:39 flowing into from the atrium to the during this period of time. But
47:45 does. So even more this graph terrible here. But it does.
47:49 even more. So you can see going in there and I'm getting this
47:53 surge of fluid. Okay, does make sense? I'm pushing blood into
47:59 ventricles. So the volume inside the in terms of how much blood it's
48:02 is increasing another way to put If I have a cup that's empty
48:07 I'm pouring fluid into the cup. the volume increasing? Yeah. Is
48:13 pressure inside the cup increasing? What you think? Yeah, it
48:20 What does that where does that fluid go? Want to go out of
48:23 cup thing is the cup has walls it can't. That's the same thing
48:27 going on here. So look at pressure is going on here. Is
48:31 pressure climbing in the graph. the same point is the ventricular pressure
48:37 in that graph. Yes. But is the ventricular pressure always staying
48:40 Atrial pressure right here. Is it underneath? Yes. Alright. So
48:49 blood during atrial sisterly moves from the to the ventricle, increasing the volume
48:59 blood inside the ventricle. The pressure in the atrium contracts and as it
49:05 blood into the ventricular pressure rises as due to the presence of the fluid
49:12 the ventricle. Okay, now, the first step, the ap valve
49:19 to be open and it has to open because you can't move between the
49:22 chambers if that door is slammed shut the purpose of the ap valve to
49:26 is to prevent backflow. It's not to prevent forward flow. So as
49:31 pressure is open, it causes or pressure is greater in the atrium to
49:35 ventricle, it causes the valves Alright. So this is all going
49:40 during atrial. Sisterly and this is starting point. All right. The
49:47 step is ventricular system. Alright. remember we sent the signal from the
49:52 . A note to the A. . Note that sat there and twiddle
49:54 thumbs delayed. And then we get Q. R. S.
49:58 R. S. Is a representation all of those contract. I'll,
50:02 of the ventricles contracting simultaneously. So all your muscles in your arms contracts
50:10 , they create tension. Right? creating tension to move something. So
50:16 example, I've got this big heavy . Got to put it up on
50:21 stage. So heavy. All come to the chair and I can
50:30 tension in the muscle but notice that left the chair. No.
50:36 what I have to do to lift chair create more attention and more attention
50:42 more attention to Finally, I create tension to lift the chair. Was
50:46 really bad angle, lift the All right. So, what we're
50:51 here in early ventricular sisterly is the of creating that tension boom tension
50:59 It reaches or or uh comes across resistance. Now, where is that
51:07 come from? The resistance is a of the blood inside the chamber.
51:15 still in your starbucks for a I'm not gonna hurt it. You
51:20 , you don't want me to just . All right, actually this is
51:22 better one right behind. I'm stealing water. Let's pretend her water
51:30 That water bottle is more full. let's pretend this water bowl is
51:34 This is like the ventricle. The ventricle, what we have is
51:39 create a contraction boom. It hits pressure inside the ventricle goes up.
51:44 at the graph. You see the go up, See how it
51:49 Does it cross over the atrial Boom? So when that happens,
51:55 A. V valve slams shut. do I want, do I want
52:00 going backwards? No. So it shut as a function of that.
52:05 does blood leave the chamber? because the other valve is slammed shut
52:12 well. Because the pressure out here the aorta is greater than the pressure
52:17 the ventricle, just like me lifting that chair, I have to create
52:21 tension and enough pressure to overcome the in that next area the aorta.
52:29 I begin squeezing. So my hand like the muscle of the ventricle surrounding
52:34 ventricular chamber. And I squeeze and squeeze and I squeeze and I create
52:39 and more and more and more And it's only until the pressure right
52:45 a result of the tension becomes greater here too. Cause that valve to
52:49 until the blood leaves. So in ventricular sisterly. Thank you. What
52:57 doing is we're creating that pressure and tension. So during this period of
53:03 the eight years relaxing. It's going its diastolic it's like I did my
53:07 . I squeezed everything out and now here ready to receive blood coming back
53:12 the system. So I'm in a state so just keep sending me
53:15 So it's right. But the vehicle now in the state of contraction.
53:22 valve slam shut. You hear a club? Right pressure begins to rise
53:30 that's what you're seeing here, pressure rising but there is no movement.
53:38 you don't see any change in the . The artist did a very poor
53:42 of doing that. It stays flat can't leave blood can't enter. And
53:50 you're doing is you're increasing and increasing the pressure more and more and more
53:54 more until the pressure inside the atria greater than the pressure outside in the
54:03 . And when that happens that's when blood will leave. Now. The
54:08 that we give to the volume of inside the ventricle at this time is
54:14 the end diastolic volume. Now it's end of ventricular diastolic. It's the
54:20 of ventricular sisterly and that's where he his name. The end diastolic because
54:25 at the end how much blood is the ventricle at the time when diacetyl
54:29 ends. Now this E. V. Is gonna be important here
54:33 a minute because we're gonna use it help calculate another value. But it
54:37 constant. But when the pressure gets than the aortic pressure, alright so
54:47 building a pressure, building up it's an isometric contraction. You guys
54:51 the word isometric from Mp one, it's when the muscle is getting more
54:55 more attention but you're not getting any of movement. What's going to happen
54:58 you create that tension, it becomes enough and then what it does is
55:04 overcomes the pressure in the aorta. simulator valve pops open. Whoosh.
55:14 the pressure is like over it's it's you've now overcome the hump and so
55:19 you don't get that isometric contraction, now getting a squeezing pressure. So
55:24 I squeeze, where does the fluid out? And what do we see
55:33 fluid leaves out? It goes as as it can and it goes out
55:37 the aorta. The pressure inside the increases. Why? Well because now
55:44 able to contract even further, I'm squeezing and squeezing and squeezing. Okay
55:50 . But I'm also squeezing volume of out into the aorta and the order
55:55 receiving a volume of fluid which causes pressure inside the aorta to go up
55:59 well. And that's what we're seeing . All this stuff. Alright now
56:08 will continue to flow down its pressure . That means the pressure inside the
56:14 sits higher than the pressure inside the , even though they're both climbing the
56:19 inside the ventricle is slightly higher than pressure inside the aorta and as long
56:24 we keep contracting, we're going to that process of driving the fluid
56:31 Now that contraction remember is a function of a it's kind of it's like
56:36 parabolic curve. I got contraction and I hit a peak. And then
56:39 happens on the other side is I relaxation and when we have relaxation that's
56:47 diastolic. And so here we are I think I got these two out
56:53 order. Here it is. Early diastolic. Sorry. And so here
56:58 are. And what we're going to is we're at this peak and then
57:05 we're still above. And just when get down to there that's when diastolic
57:11 . Alright. We created that We squeezed everything out and then the
57:15 begins to relax. And then when pressure in the aorta which is now
57:22 because I pushed all this fluid in now I've got a muscle a ventricle
57:28 relaxing, that muscle begins to relax eventually the pressure inside the ventricle gets
57:34 . And so which way does the want to go? He wants to
57:38 back to the ventricle like look there's path of least resistance it starts running
57:42 that causes semi lunar valve to slam . So we get our 2nd sound
57:47 up. Now we have two valves , the valve is closed and the
57:55 and the semi lunar valve is Alright the muscle is going through a
58:00 of relaxation. So atrial pressure is , much less. So you can
58:10 where the atrial pressure is. Way here, ventricular pressure is over here
58:14 it's less than the aortic pressure which right there as well. And what
58:18 going to see is that that pressure going to continue to drop as that
58:23 relaxes. All right. Think about the tension in a muscle,
58:29 Cardiac muscle the same thing and then the muscle feels good, doesn't
58:34 Right. Right. It's doing the thing. But blood can't enter in
58:40 the aorta because the semi lunar valve , blood can't enter in the
58:44 V valve because the pressure inside the is still greater than the pressure inside
58:48 atrium. And so there's no flow the ventricle. And so we end
58:53 with a volume of blood because we squeeze it all out. We never
58:58 all the blood out. All That is there at the end of
59:04 . That's what we call in systolic . So, I have an in
59:08 volume in systolic volume. And the between those two is how much the
59:13 pumps, which has a fancy name the stroke volume. So mathematically stroke
59:20 equals in diastolic volume minus in systolic . I think we'll see that in
59:24 second here. Alright. So early diastolic. Remember we're in a state
59:30 relaxation. We're not in a state reception? We're basically in a state
59:34 returning back to a state of And the only time we can begin
59:38 receive again is right here. When ventricular pressure as a result of that
59:45 drops below the slowly rising atrial Why is the atrial pressure rising?
59:53 I just pushed a whole bunch of into the systemic circulation and that's pushing
59:56 forward, pushing brush forward and blood returning back to the heart on the
60:00 side and it's just slowly filling up atrium. And as the pressure inside
60:05 atrium rises and the pressure inside the falls, they'll create a tipping point
60:10 a crossing point which results in the . V valve opening and all that
60:15 simply moving down its pressure gradient into ventricle. So, notice blood doesn't
60:22 need to be pushed into the It naturally goes there because of a
60:26 gradient. Can I time out for second? Just just time out gradients
60:34 gonna become the single most important thing you to understand. Not just pressure
60:39 , but just gradients in general. you deal with physiology alright. Things
60:44 from areas of high concentration, low things move from high pressure to low
60:48 . Alright, when you hear the gradient, you're jumping back to
60:53 When you learn things go down, ? You looking at the diver,
60:58 get up on top of the What is a 30 m? 32
61:03 ? The how about a 10 m ? 10 m? That's 30
61:09 Do you stand on your hands and that? Which way you gonna go
61:17 ? Always down, right? Always down. We always move down
61:23 Okay to go up the ladder, had to work. But when you
61:27 up there it's just gonna happen. that's the same thing that's gonna be
61:32 gradients. Alright, pressure gradients. move from the area, high pressure
61:35 low pressure volume. I have more . Less here, I'm gonna move
61:40 that gradient. And so that's what's on is as the atrial pressure
61:44 the blood pressure or sorry, the volume increases the pressure in here,
61:49 drops below that blood is gonna then go leaping forward and notice what happens
61:57 . And late ventricular diastolic blood leaps the ventricle is not pushed, it's
62:06 in simply because the pressure caused the . V valves open. When the
62:12 V valve opens, blood flows in then we returned back to where we
62:21 . Then we go to ventricular right? We have an early and
62:25 stage and then we're back to diastolic we just repeat it over and over
62:30 over again. The big thing about is if you can learn this,
62:37 learned how the heart works. All gotta do is just separate it
62:40 Make it simple for yourself. What going on at the P wave?
62:46 this is what pressure looks like in two chambers? What does that mean
62:50 regard to the valve? Is it or closed between them? Oh it's
62:54 . Oh it's closed. If it's , things can flow through. If
62:58 closed, things can't flow through. does it open? Because pressure on
63:02 back side is greater. The pressure the front side. Why is it
63:06 ? Pressure on the front side is the pressure on the back side.
63:10 want blood to flow in a particular . What about the volume? Volume
63:15 dependent upon the direction of blood If blood is moving right, you
63:20 all those things together, you get picture and it's easier just to kind
63:25 ask that question. Here I am here I am here here I am
63:28 here I'm here. What's going on four places? Think you can do
63:34 ? Everyone should nod your head and yes, I'm not an Aggie.
63:38 know I probably have a post back . Who's an Aggie And I'm
63:42 I'm not trying to make fun of . Let's make fun of people went
63:45 texas instead. Yeah, we're good it. two people are nodding their
63:52 . How about over here All right in the back, We're good people
63:59 their history homework. You guys You've got questions about it. Go
64:17 . Mhm. So so I would that this this particular poorly drunk,
64:26 mean, is really what is I if you there are better ones out
64:30 . I've seen worse than this. , the physiology textbook I use for
64:34 upper level students. It's even worse they don't even use color. Just
64:39 but I think in terms of what going on here, the picture doesn't
64:45 a good job. And partly it's , you know, the artist didn't
64:49 between the two. It should be exaggerated. So, you can see
64:53 just like they did down here. can see a slight exaggeration. These
64:59 accurate numbers, they're just points of . And they're just saying,
65:03 here's this difference. Okay, now swaps. And then when I get
65:07 here, it's like, oh, I'm gonna be like, so and
65:11 gonna stay like this until this one over. Now I'm I'm less and
65:15 just kinda how it works. Yeah, this is where bad artists
65:23 cause huge problems Okay with that. right. So, what I wanna
65:30 is I wanna I wanna move on deal with something else that with regard
65:36 how your heart works. And I we're uh we've got about 15 minutes
65:41 I think we can cover all this . So, the first thing I
65:44 to deal with this cardiac output, output, bite up. And it's
65:48 simply the amount of blood pumped by single ventricle and why we say single
65:53 because each side is doing the exact thing. So, the cardiac output
65:57 that ventricle done in one minute. so this is usually expressed in liters
66:01 minute. And it's determined by two , fairly simple heart rate and stroke
66:06 . All right now, the heart is the number of beats.
66:09 what you do is you can sit and count for 60 seconds to see
66:13 many beats you have. There you . There's your heart rate. All
66:16 , You can do it in 10 and multiply by 66 seconds. Multiplied
66:20 10. All sorts of fun. ways that you can do the calculation
66:22 you want to. All right, stroke volume is the amount of volume
66:26 blood ejected per beat. And this measured in mils per beat.
66:30 if heart rate is beats per now you've got measures, you're doing
66:34 per beat. So, you can those two things. Thing is,
66:38 you really measure your stroke volume? we go out? And I
66:41 other than, you know, cutting big giant hole in you and doing
66:45 . No, we can't. here's some of the interesting.
66:51 so your cardiac output is gonna vary with your heart rate and or stroke
66:55 to meet the special demands of your . Alright, So, when you
67:01 , what's gonna happen? Your heart goes up, right. And the
67:05 it goes up is because now there's greater demand for the auction and the
67:09 your body is needing in order to whatever the activity is. So,
67:15 see your heart rate go up. you also see your stroke volume go
67:19 . So they kind of work hand hand to increase that cardiac output.
67:24 right. Now, the examples I up here are also some really,
67:27 interesting ones. So, for if you have a small heart,
67:31 a child has a small heart and you go and measure the heart rate
67:34 a small child, it sounds like hummingbird. Because the truth is,
67:40 body is trying to keep a constant output. That is equal regardless of
67:46 or size. It's basically like this how much fluid I need to be
67:51 at any given time. So, you have a small heart, it
67:53 to work harder to move that same . Right? So, you have
67:58 small stroke volume as a result of small heart because just size. And
68:04 to compensate for that smaller heart and smaller stroke volume, your heart rate
68:09 up. Right. And so you imagine her heart rate and her mother's
68:16 rates even faster because kids are about run on the street. All
68:23 Yeah, Alright, Large heart. our athlete that is an athlete.
68:29 type of athlete is that sumo wrestler want to mess with them. All
68:33 . He has a very, very heart. This is why I picked
68:36 picture because I think this is incredibly , Right? This is a big
68:41 and this person has a big So when his heart beats, he's
68:47 trying to maintain a cardiac output. this particular athletes heart normally beats at
68:53 a lot slower than the rest of . Right, would be thumb,
68:58 , thumb, thumb, right? you end up with a much much
69:02 heartbeat. Alright, And the reason is because they have a very large
69:08 volume, bigger heart, more blood pushed. They don't need to have
69:13 many heartbeats. And so that's why have a slower heart rate. All
69:17 now, as I said, any of physical exertion there. I like
69:22 one of the best example. Your rate is gonna increase to deliver blood
69:27 , right? Oh, my muscles blood now. So I need to
69:31 it there now. So, the way I can do that is if
69:33 start moving it quicker, Right? I also need what's in the blood
69:41 . I need more of it. the other half of that is I
69:44 going to increase my stroke volume. much blood I'm delivering to ensure that
69:51 particular organ gets what it needs. cardiac output. Both things are gonna
69:57 up. Alright, so you've probably this, your heart when you like
70:01 you've exerted yourself where your heart is hard, you can feel it
70:06 It's going thump, thump, thump, thump, thump. It's
70:08 fast. But you can also feel exertion because what it's doing is it's
70:14 and contracting and pushing more fluid at same time. All right. So
70:21 increase both as a function of Now there's a whole bunch of different
70:25 that can affect your heart rate. so these are some of the external
70:29 that are going to act on the . A. And the A.
70:31 . Node. Alright, so we autonomic innovation. We're going to have
70:34 types of hormones and different types of and drugs. We're going to focus
70:38 primarily on the on the two middle the first and the second one,
70:41 on the other things. Collectively these are referred to as krone tropic chrono
70:47 with time. So what we're doing we're affecting the timing of the
70:52 the rate of the heart. All . So with regard to the cardiovascular
70:57 , we're talking about the autonomic nervous . Keep in mind the heart beats
71:01 its own, it has its natural . The natural pace is regulated through
71:05 structure. First thing we talked about . S A node. It will
71:12 beat. All right. That's what does. First thing your heart does
71:16 it develops it produces these cells before even have muscle cells and it already
71:21 there and creates this beating. So what we wanna do is we
71:27 to either increase it or decrease it this is where the autonomic nervous system
71:31 into play. All right. It's be controlled through the medulla and there's
71:40 regions. One is called the cardio Torrey region. One is called the
71:43 inhibitory region. Fancy words to make heart grow faster, makes the heart
71:47 slower. Right? And what we're do is we're gonna respond reflexively,
71:53 mentally, right? We're not we control it. It's a reflex in
71:58 to chemicals pressure in order to maintain needs that our body has.
72:03 that's what homeostasis is. All And the other thing is your heart
72:07 knows how to respond to over filling saying no no no quit sending
72:11 So they're gonna control and regulate how is returning to the heart, as
72:16 as how the blood is pumping the . Alright. So with regard to
72:20 innovation, this is really, really and really simple acceleration occurs in the
72:25 of sympathetic activity. All right, am P. One We learned about
72:31 and parasympathetic autonomic nervous system, cardio is sympathetic. All right.
72:38 what we're using here is we're using spinal nerves. T one through
72:42 Five. We go to three different . S A node, the node
72:48 the rest of the mild cardio. ? Why would I do that?
72:55 , what I wanna do is I to ensure that I'm sinking up the
73:00 , the ventricles in order to get to work in unison. I don't
73:04 the atrium to start contracting faster and ventricle not keeping up. I want
73:10 of those things to work in So this is responsible for ensuring that
73:16 that is going on. So that's we increase our heart rate. We're
73:19 affect the control the auto rhythmic cells make them contract fast and we're gonna
73:24 how we do this in just a . But the other thing is the
73:28 cardio myocardial is represented by the contract cells and I'm stimulating the contract I'll
73:34 to work harder. All right. other words, I'm making them contract
73:41 and faster so that they create more quicker. It's beating out of your
73:50 like that. That's what's going All right now, there's also innovation
73:55 the coronary arteries and what this does it will actually induce dilation or in
74:01 depending on which arteries you're looking, gonna be dilation further on. You're
74:04 see resistance and it's actually speeds up allows for more volume and we'll deal
74:09 that when we deal with the blood . All right, to slow down
74:14 heart. This is where parasympathetic comes . It's through the vagus nerve,
74:18 , That's the one nerve we learned we talked about the autonomic nervous system
74:22 you gotta know vagus nerve because it's the big weird one. Alright.
74:26 what we're doing here is we're decreasing this is interesting. It's the heart
74:32 . We're not worried about force of . So it's not going to the
74:37 . Alright. It's dealing primarily with two nodes. Yes and the
74:40 V. Node. So we're doing we're slowing down the heart but we're
74:45 gonna worry about force of contraction that take care of itself because of some
74:50 the inherent qualities of the heart. we say something is positive a positive
74:57 tropic when it increases the heart All right. So sympathetic innovation is
75:04 chrono tropic. And what it's really here and I don't want to spend
75:08 too much effort on this. Is it's affecting that curve. That action
75:13 that we talked about. Remember we the action potential is dependent upon sodium
75:17 and calcium. Alright. So if want to increase the rate at which
75:21 climb then I want to make sure have more calcium coming into the
75:27 So that causes my my my curve go upward. And what I wanna
75:32 is I want to increase the rate which I go down but I don't
75:36 to go down as far as I to. Alright. So what I'm
75:39 do is I'm going to reduce the of potassium that is being allowed to
75:44 back and forth. And so what up happening is I climb fast drop
75:48 . But I don't go down as so I can climb fast again.
75:51 so that means I can get more in the same period of time as
75:55 did when I started. And that's this picture is. Trying to
75:57 You see here the gray, you see that's the normal path. Notice
76:02 . I don't go down as far ? So I'm allowed to return back
76:07 threshold quickly. Look at my slope relative to my slope there and you
76:11 just pick any one of those too for one of them is like this
76:14 for the other ones like that. I rise quicker. So that means
76:17 getting more heartbeats because I'm causing the fire with greater frequency. Alright,
76:25 increasing calcium decrease in potassium. All now, the other way we can
76:32 this we have hormones in our right? We can increase their
76:39 Right? Someone jumps out of the and go boo, fight or flight
76:43 . What do we do? We our body with epinephrine? What does
76:46 epinephrine do? It does the exact thing. It acts on these cells
76:50 create that and make it happen, hormone does the exact does something
76:55 It basically makes them more responsive to epinephrine and norepinephrine that's in circulation.
77:01 other drugs for example can do similar . So caffeine basically um inhibits the
77:09 so that this whole thing speeds There's other drugs that can do that
77:13 well. Not so interested in knowing . So positive. Corona tropic,
77:19 do they do increases heart rate, chronic topic on the other hand are
77:26 be through the parasympathetic, it just the opposite, it decreases calcium
77:32 it increases potassium permeability. And so you end up doing is you end
77:37 spending more time below thresholds to look the slope there versus the slope there
77:45 . You do know that's incredibly Alright I don't care if you guys
77:49 leaving. Just don't make a huge about it. All right.
77:56 You mean you guys are adults you choose when to get up and go
77:59 don't be loud about it. And then again there are other
78:05 So if you have probably heard beta , beta blockers block or prevent epinephrine
78:10 norepinephrine from binding to the receptors and you don't when you aren't able to
78:16 those receptors then you you end up a reduction in the activity in other
78:21 epinephrine or norepinephrine epinephrine and norepinephrine increase rate, blocking those receptors prevents it
78:28 happening. And so you decrease So krona tropic agents positive or negative
78:34 parasympathetic stroke volume we said is something we can calculate. We just need
78:41 know what the end diastolic volume is what is left at the end of
78:45 versus what is the end at Sicily the difference between that's how much blood
78:50 move from the beginning and the So that's your stroke volume. All
78:55 now there are three factors that affect volume and this is gonna sound a
78:58 scary because we use big words but already understand that these are gonna be
79:03 . We have things called pre We have things that's called external in
79:07 tropic agents, things that are going affect the ions involved. And lastly
79:11 load. Alright so let's deal with venus return. Alright, the pre
79:18 . This is one of the cool about the heart. You don't need
79:22 tell the heart how to behave. heart already knows how to behave.
79:24 actually follows something that two guys figured by just making observations whatever you give
79:31 heart. The heart's gonna work In other words the heart pumps what
79:37 give it. So if you constrict veins and push more blood into the
79:43 right. In other words you push blood in the heart. The heart
79:45 at and says okay I'll pump that so it basically responds to what you
79:51 it. All right? So if change how much blood I'm getting in
79:57 beginning of the process that's diastolic diastolic ? So I'm receiving blood during dia
80:04 if I increase my in diastolic What's gonna happen to my stroke
80:09 Mathematically says stroke volume equals in diastolic buyers E. S. V.
80:15 if I increase E. D. . What happens to stroke volume?
80:20 increases? Right. Let's make a number. E. D.
80:23 Is 10. E. S. . Is one. The difference between
80:26 two is nine. Alright if I E. D. V. And
80:29 it to 15 and I don't change S. V. 15 minus one
80:33 14. It grows. So stroke increases so if I increase the pre
80:40 the amount of blood that the heart gonna pump back out is also going
80:45 increase. That's the stroke volume. ? That's pre load, that's venus
80:49 . And this is based on the Starling law. Alright. That's the
80:53 phrase there. The on a tropic are the external factors. So autonomic
80:59 stuff. We've already talked about. happens with sympathetic innovation. What does
81:04 innovation do, increases contract I'll So if I increase the amount of
81:10 I make the heart beat harder. what that does is that gives me
81:14 greater drive to push things outward so supports what frank Starling does. So
81:19 that increases calcium is going to increase volume. Anything that decreases calcium reduces
81:25 volume. Okay and then the last and I'm sorry I'm keeping you an
81:30 minute life is hard here? Right the after load? Alright? If
81:36 have greater pressure in the arteries, my heart have to work harder to
81:41 blood into the arteries? Yeah. it this way if you want to
81:48 this room and I'm standing in front the door, are you gonna have
81:50 work harder to get out of the or get through the door? Yeah
81:54 gotta push me so you have to harder to leave. And that's the
81:58 thing when there is an increase in in the periphery, that's your blood
82:03 . Then my heart has to work to overcome the pressure to push the
82:08 out. This is your after All right in other words what I'm
82:13 is I'm dropping my E. V. If I'm using the same
82:16 of work I'm not able to push as much blood and so now I
82:20 more blood to push out the next and the next time the next
82:22 So in order to do that work have to work harder at the front
82:26 . Come on in dr Gifford. this right here is a simple summary
82:33 those last four ideas. Alright so load what I give to the heart
82:41 load, the resistance in the blood . And lastly what's going on
82:46 In other words as I affect the of calcium. If I increase calcium
82:50 decrease calcium I'm gonna affect that stroke . Both positive and negatively. Thank
82:55 for being patient for the last three . I'll see you on thursday we
83:03 to
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