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BIOL 2302 Human Anatomy & Physiology II - 2302_lecture04_0126
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00:11 Good morning everybody. How are we doing today? Did everyone get soaked
00:15 Tuesday? Yeah. Did you actually walking like when it was raining in
00:22 horrible nastiness? Yeah. Okay. , what we're gonna do is we're
00:27 to talk about the heart. We've dealing with the blood. We've learned
00:31 couple things about blood. Probably something than you didn't know before. I
00:35 right, blood is made up of made up of cells or formed
00:40 We have red blood cells, white cells, and we have platelets.
00:45 kind of understand their big picture of . Right? And so blood is
00:49 only a third of the circulatory I'm not by volume. I
00:53 there's lots of blood. How much do you guys remember about five
00:58 Not an important number, but, know, trivial stuff, sticks,
01:01 in my head. And Well, bad. All right. So,
01:04 circulatory system has to be part. has the heart which is a
01:09 it has blood vessels, or the . Vasculature is what is used to
01:14 the blood around the body as a of the pumping of the heart and
01:17 the blood carries all the stuff to cells or away from the cells so
01:22 you can move materials through the Alright, so, our focus today
01:26 really gonna be on this first this pump system, This heart and
01:30 it does. Um And so in to understand this. I think the
01:35 first thing we're gonna have to do we're gonna have to just get one
01:40 thing out of the way regarding the . Alright, because there's terms here
01:44 you heard or used before, you know them. But just in case
01:48 you don't, I need you to of take these minimum details so that
01:54 can kind of understand some of the that's going on in and around the
01:58 . So the vasculature has three parts it. There's there's more than
02:02 But this is like the three Alright, you can think of this
02:06 highways and streets. Okay on a , you're trying to get between two
02:12 . If you live in Katy, get on I 10, you
02:15 go go and if you're trying to to Mcdonald's, you just stop the
02:17 on I 10. No, what you do? You have to take
02:21 exit and get onto a surface street finally you find your way to that
02:26 all right. And that's kind of we're dealing with here. The highway
02:30 are the arteries and the veins. , They don't play a role in
02:34 sort of gas exchange. They are the expressways between two points in the
02:39 arteries are always going to be moving away from the heart, veins are
02:44 going to be moving blood to the . So, it's a nice simple
02:48 is I'm going to or from right vein where all the fun stuff takes
02:55 . In other words, where all exchanges taking place between the external
02:59 like when you breathe in and you in that oxygen, you're breathing and
03:02 moving that carbon dioxide that exchange between environment and the body is occurring at
03:08 level of the capillary. Similarly, you're looking at a cell and that
03:12 is receiving nutrients or or removing waste that sell that stuff is picked up
03:17 the level of the capillaries. So have kind of this general structure
03:22 we have arteries that carry blood away the heart down towards the cells or
03:27 the lungs or whatever. And it's that level of the capillaries around that
03:32 , where the exchange is taking place then when that exchange has occurred and
03:37 blood is now moving away from the of exchange, you're gonna be traveling
03:41 the veins. Okay. And so using this nomenclature now because one of
03:45 things we're going to see about the is that it actually has some arteries
03:48 veins associated with it. And if didn't know what those terms were,
03:52 could be sitting. Right, so want to avoid the uh All
03:57 so what is the heart? It's place where love grows? I get
04:05 giggle. I got one giggle. you. No, no, it's
04:09 where love grows, it's where No, is it where life
04:14 No, it's a it's a It is literally a mechanical structure.
04:20 . It's a hollow four chambered at least in humans and other organisms
04:25 gonna see, or one of us going to see that there are other
04:30 of hearts out there. But for it's a four chambered structure and there
04:33 three basic features that you need to aware of. The first is this
04:38 pump type structure. What you just ? It's a hollow organs. The
04:42 , Yeah, it actually has two to it. We're gonna see what
04:45 two pumps do. Secondly, it these vessels that deliver and allow blood
04:50 leave these two pump structures. And , there's gonna be a pair of
04:55 that are gonna control which direction blood gonna be flowing because blood flows in
04:59 very specific direction through the pump Alright, so we're gonna just kind
05:05 walk through them to pump system. , The first thing everyone I want
05:09 to raise your right hand, I swear that my I understand where my
05:15 is, and I understand where my is. Look at where my right
05:18 relative to your right, Why is ride over here? Because I'm facing
05:23 guys see it's still my right. if you look at the pictures and
05:27 like that, your brain is gonna wait a second writes on the wrong
05:30 , It's not on the right It should be over on the other
05:33 . But remember you're looking at a . So anytime you're looking at a
05:36 , remember the right of the thing you're looking at is a dead person
05:41 the table and that's what you're So this is your right, when
05:45 dealing with the heart, you need know where your right from your
05:47 Because we're always going to begin over on the right hand side, it
05:51 life lots easier. Alright, so have a right side and the left
05:55 of the heart. What we will is that the right side is the
05:59 pumping system. Its purpose is to blood to the lungs and then blood
06:06 from the lungs returns back to the and then the left side of the
06:10 pumps that blood to the rest of body. Now, in saying that
06:16 don't want you to think that the only serves the left and the right
06:19 . In other words, the right of the heart doesn't serve the right
06:21 of the body. The left side the heart doesn't serve the left side
06:23 the body. That's not how it . The left side of the heart
06:26 your entire body, but the left the right, but it's what we
06:30 to as the systemic circulation. The side, this side is pumping blood
06:36 into both lungs, the left and right, so that you can deal
06:40 gas exchange. All right now, side has two chambers that are
06:46 Remember we said this is a four structure. So it's hollow and it
06:50 these four chambers. Alright. The chambers on both sides are called the
06:57 . Alright. That's plural. Atrium singular. The two lower chambers or
07:01 chambers are referred to as the So we have a right atrium.
07:08 have a left ventricle. Sorry, ventricle. That's why I say
07:12 I have no idea. Right Then over here we have a left
07:15 and left ventricle. Okay, pretty anatomy. And you can draw this
07:21 . Oh I forgot to pull out pen. Let's see if I can
07:25 this on the slide. Just because people have taken a and p.
07:30 . You know exactly what my heart like, right? Because I'm the
07:33 artist ever. All right, this your heart. Pretty Huh?
07:44 See you don't need to be an to be an anatomist. And then
07:48 you do is you just put your old crisscross in there and then what
07:51 have up here, That's your right down there. That's your right ventricle
07:56 here. That would be your left . That's your left ventricle. Pretty
08:00 . Huh? So what we're gonna is we're gonna push blood in and
08:06 is gonna go out. We're gonna where those vessels are and why it
08:08 out that way and then blood comes in and then it pushes out up
08:12 the middle again. All right. not going back through the atrium.
08:16 structurally the cross doesn't work perfectly. . So what we're gonna do is
08:22 propelling blood from the right atrium into right ventricle, right ventricle propels blood
08:28 to the lungs. Blood coming from lungs goes into the left atrium from
08:33 atrium, you're pushed into the left and the left ventricle is responsible for
08:38 the blood out into the systemic circulation that all your organs and stuff can
08:43 the blood they need in order to . Now the way we get that
08:47 there is through these just don't like . Let's see if we can push
08:51 down a little bit. Oh, that thing. All right. So
08:55 we're dealing with the vessels, how blood get there? These are the
08:59 vessels. These are those arteries in veins that we're talking about. All
09:03 , So there's two major arteries that need to be familiar with. So
09:08 said the blood is leaving the heart two different places. One it's going
09:12 the lungs, one, it's going the to the system to your entire
09:16 . And so the vessel that's leaving go to the lungs is called the
09:22 trunk. Now it's called a trunk it starts off as a single vessel
09:26 it splits. And so you get large branch like structure and you can
09:30 it here um You can see it , here is the pulmonary trunk.
09:38 this thing altogether. It's big, huge. And what it's gonna
09:44 it's gonna divide into the left and the right pulmonary arteries. And that's
09:48 the names come from. All The other one is the aorta.
09:52 you've all heard about the aorta at once in your life, You may
09:54 know what it is, but you've the word right Aorta means literally big
09:59 and it is the big artery here leads from the left ventricle and there
10:04 is, there's the aorta and you see other blood vessels branching off the
10:08 of that thing. Alright, So we have now on the right hand
10:14 , we have the right atrium, have the right ventricle. Blood leaves
10:18 heart via the pulmonary trunk splits into two artie's left and right pulmonary
10:23 and then blood returns back. We talked about that yet. And then
10:26 we're gonna do is we go through left artur or left atria down the
10:30 ventricle and then up and out through aorta, which then delivers blood to
10:35 smaller arteries, which will then eventually down to your different organs and ultimately
10:41 to capillaries now to get the blood the heart. We need to have
10:47 and there are two major veins that need to deal with or major groups
10:51 veins is probably a better way. first is how do we get blood
10:56 the right hand side. We always on the right hand side. And
10:59 structure coming in on the right hand is called the vena cava.
11:03 It's like the cave vein is the you can think about it vena
11:07 Now there's one that goes up and that goes down the branch, there's
11:10 branch in there and so you'll see vena cava and superior vena cava.
11:15 they join together and they form that that empties in directly into the left
11:22 . Excuse me? Right atrium. , so vena cava, right
11:26 right ventricle, pulmonary trunk, pulmonary back down. And then the way
11:30 get back down is via via the veins. Alright. And so in
11:35 little cartoon, once again you can here here are the left pulmonary
11:39 right pulmonary veins notice but its All right. They're coming in as
11:44 group and then they join up and into the left atrium from the left
11:50 down the left ventricle from the left out through the aorta and the systemic
11:54 back to the vena cava. And can just repeat this process over and
11:57 and over again. All right now where I have fun with you guys
12:03 I like to have fun. so we enter the heart via a
12:07 . So that starts with a Then we go into the atria.
12:11 an A. Then we go into ventricle, that's A V. And
12:14 we leave out via an artery and we go through the system and then
12:18 come back via vein. Then we into an atrium, then it's a
12:22 and then we go out through an again. See that a vis a
12:26 a vis a vis notice we're ignoring . All right. But this is
12:31 real simple system. And so we already see now that there is a
12:34 flow. There is a kind of that is occurring as a result of
12:38 structures. Alright, interview the vein cava atrium ventricle on the right hand
12:45 . Leave via the pulmonary trunk which pulmonary arteries, return back via the
12:50 veins. I haven't told you this and I'm already sure I've already said
12:54 invited you any things for what they or for what they look like or
12:57 what they do. So, you see the name pulmonary just tells you
13:00 coming from the lungs. So pulmonary , left atrium left ventricle out via
13:06 aorta. Now if your flow is this, there has to be something
13:11 directs the flow. Alright. We there's a third feature that the heart
13:16 and that feature is valves. All . Now the valves, there's two
13:24 of them. The nomenclature kind of all over the place. Now,
13:27 good news is that on an exam not going to just give you one
13:31 if you've memorized something else. Usually I'll do is I'll give you both
13:34 if something has two names. All . So you can kind of pick
13:38 choose. And part of the reason do this is because I'm lazy and
13:41 like to memorize easy things. I like to always memorize the hard stuff
13:46 I'm lazy. All right. But two veins, they include the atrial
13:51 valve. Our veins valve, excuse ? Atrial ventricular valves and the semi
13:55 valves. Now you can go and all that stuff. But why do
13:57 think they call them a V Atrial ventricular. Why? Between the
14:05 ? The ventricle. Okay so it's doorway that lies between those two
14:09 Okay now I said they we name for what they look like or for
14:12 they do. So that's for what do where they're located semi lunar.
14:17 do you think we call him semi half moons? Alright, so there
14:23 go. That's well you can't see there. It doesn't look like but
14:26 you're sitting there cutting them up you're oh look it looks like a little
14:29 moon. Right. See the heart magical. That's where love comes
14:33 Has moons in it. All right we have to a v valves.
14:40 one on the right one on the because we have a left side of
14:42 heart and the right side of the and what we're doing is we're directing
14:44 between the atrium, the ventricle. there's a right A V valve.
14:49 I'm abbreviating it by nomenclature, I say right, atrial ventricular, but
14:53 three syllables and navy is easier. ? So we have a right A
14:57 valve. It has another name. other name is Try cusp it.
15:04 , so now we're naming it based what it looks like. It has
15:08 cups. All right. So three like structures that help to serve to
15:14 as a door. So instead of being two, there's three cups and
15:19 the left. Davey valve is called bicuspid because it has two cups and
15:25 goes by another name, which is confusing. It's called the mitral
15:29 Now, you probably don't know what metra is. Anyone here know what
15:32 metra is? Here's a nice little pursuit thing. Right? You might
15:38 able to use it sometime in word because it's a five letter word mitra
15:44 is the hat that a bishop And so it has a shape like
15:48 hat. That's where they came up a name, like what? I
15:52 even know what a bishop is. worry about it. All right,
15:55 the easy thing to do left and . A V valve and knowing which
15:59 which and I will put on the right, would be left. A
16:05 valve in parentheses, mitral valve, bicuspid, something along those lines.
16:12 , now that's how I do In the future, you may come
16:17 some horrible nasty anatomist who makes you , just one thing. So that's
16:23 I teach it all to you. right. So we have these two
16:26 . They lie between the atria and ventricles. We have another set of
16:30 , these pairs of semi lunar valves their name for where they're located as
16:35 . They lie between the ventricles and artery in which they are feeding
16:40 All right. And so we have pulmonary valve and the aortic valve.
16:45 aortic valve sits between the left ventricle the aorta, the pulmonary valve,
16:51 between the right ventricle and the pulmonary . And so what we have now
16:58 we have the structures that are going direct the flow of blood in a
17:03 direction because these valves are one way . One way doors right? So
17:11 one side, if you push on valve, the valve will open up
17:14 the material can flow through. But you push the other direction, the
17:18 slams shut and nothing can go And so that means blood is directed
17:23 the in the direction in which the can open up. So blood is
17:28 this way and the valve opens this blood can go through and then the
17:32 that we open and close is based pressure will get to learn all about
17:36 a little bit later when the pressure greater on on the backside, that
17:41 shuts and blood can't go backwards. that means when my heart is pumping
17:47 a function of the muscle, I'm blood from one chamber to the next
17:52 the artery in a particular direction. I go from right side, right
17:58 with the vena cava, vena cava the right atrium, right atrium through
18:02 right A. V valve down into ventricle. The right ventricle, right
18:06 uh creates pressure, pushes causes the to pass through the pulmonary valve into
18:14 pulmonary trunk. From the pulmonary You go into the lungs, come
18:17 back to the pulmonary veins, empty the atria? We the pressure inside
18:23 eight year. When it's greater, ventricle opens up the valve, the
18:26 A. V valve pushes blood into left ventricle from the left ventricle.
18:31 it creates pressure, it causes the to open. So your aortic valve
18:36 and blood goes out into the systemic . And you've just learned the path
18:43 flow of blood through the heart. side do we start off right
18:50 Always. Always just for those who up here in the States, did
18:54 guys learn how to pledge allegiance to flag, Which hand do you do
18:58 with? Do it with the say an oath, right hand.
19:05 use the right hand really easy. . You can do it on a
19:09 flight if you forget. Oh And then else that's your cheat
19:15 Right? My right hand, you call somebody over when you do
19:18 So you might want to just kind like, Oh yeah. All
19:22 So the purpose of the valves is cause or direct flow through the heart
19:29 a function of the, the activity the heart. So this is our
19:39 , right? We're now just kind breaking it up. Remember what we're
19:43 be looking at when we talk about , When you hear the word
19:46 what does that imply? It's in word circulation. What what what does
19:51 imply? It's a circle. so everything is in motion all the
19:56 . All right. So you're not working on one side and the other
19:58 sitting around as things move on the hand side, things are gonna move
20:01 the left hand side and vice Right? It's like ring around the
20:06 . I used to actually do this the classroom when we have more
20:08 Ring around the rosie had a couple people up here and make you do
20:11 guys remember ring around the rosie hold , you move in a circle and
20:14 a little little bitty ring around the pocket full of posies. It's a
20:18 little ditty about the black plague. you didn't know that ashes ashes,
20:24 all fall down basically talks about dying , are there to make it smell
20:30 , but you can't do ring around rosie if someone stops right, everyone
20:34 has to move at the same And that's what circulation is the heart
20:39 it's moving, all the blood is at the same time. Now,
20:42 said that there are two circulations. have the lungs and we have systemic
20:48 , but they're congruent. We're not , they're there, they're in
20:53 I'm blanking on the world right All right. So what we're doing
20:56 as we push blood into the pulmonary , we are also pushing blood in
21:01 systemic system just as both the left the right side of the heart are
21:05 blood as a function of us pushing . So, you need to think
21:09 all this stuff is gonna be working . So, we talk about the
21:12 side, we're actually dealing with pushing were receiving blood from the systemic and
21:17 blood that we're receiving from the systemic lacks oxygen. And so what we're
21:21 is we're taking that blood that lacks . What we wanna do is we
21:24 to oxygenate it. We want to oxygen in it. So we're going
21:27 push blood into the pulmonary system where gas exchange can take place so that
21:32 blood can become oxygenated. And when blood comes back to the left side
21:37 the heart, we now have oxygenated and that blood is now going to
21:42 pushed by the left side of the out into the system to provide oxygen
21:46 all the cells in your body. now. I'm not saying anything here
21:50 particularly complex or difficult, but it really easy to forget that we're dealing
21:55 these two different things. We're separating out so that we can understand the
21:58 system together. So both sides are exactly the same thing at the same
22:03 , even though the systemic circulation is much larger. So if you were
22:07 clamp off the two systems and try measure the amount of blood in each
22:10 them, you'd find that there is about a 3.5 to 4 fold greater
22:14 of blood in your systemic circulation than your pulmonary system. That's just a
22:19 of size. I think. How you are like me, look at
22:22 , I'm a big guy, is my here's my chest is in
22:26 lungs, my lungs relative to the of my body. Pretty small,
22:32 ? But the amount of blood that's moved is about 80 mils. And
22:36 each time I'm pushing 80 mils out moving 80 mils in. So,
22:41 a small amount of blood through both parts. Each time my heart beats
22:46 that's what this heart is responsible for moving that 80 mils of blood.
22:53 or take. All right. the reason it does this, we
22:57 a name for it. We call ventricular balance and it just ensures that
23:02 system is in constant motion, constantly blood. So that's kind of the
23:07 overview of the heart and what it's to accomplish that seemed particularly hard.
23:11 is that kind of easy to You can come up with a song
23:15 come up with a cadence or draw picture, right? Just draw your
23:19 heart and say this is where it in. This is what passes
23:21 You can can you guys do Is that easy to do?
23:25 now, the other thing, I'm gonna point out this is just something
23:28 whenever you're looking at one of these , remember what we said that blood
23:32 always always always read. But what do is there's a different relative levels
23:36 red. So, veins are usually blue arteries are usually painted red and
23:43 that indicates is actually oxygenation. But a problem when you're dealing with pulmonary
23:52 , right? Because the blood coming of the heart through an artery is
23:58 . So, kind of make sure you're looking at these pictures, what
24:01 I what am I actually seeing Right? So, uh, this
24:06 trying to show you the lungs and can see here here's an artery and
24:10 this case this picture is trying to the state of the blood, not
24:17 an arty and what's a vein. makes sense. Okay. All
24:23 Yes, ma'am. Why don't you ? Right. Okay. So what
24:40 was saying, So the question is right, you said something weird
24:43 wayne. That didn't sound right to that you said and it's what you
24:48 , right? I think you heard you said your body has unequal portions
24:52 blood in the lungs and in the of your body. But it's moving
24:56 equally and that those two things can true. Right? So, I
25:02 have a leader of blood. I'm up numbers now. Okay, I
25:04 a liter of blood roughly here in lungs. I have four liters in
25:08 rest of my body. But my isn't pumping one liter of blood at
25:12 time. It's pumping 80 mils of . So that means the right side
25:18 my heart is pumping 80 mils in my lungs. That means 80 miles
25:23 to come out. And then that that's left now has to be pumped
25:28 the systemic circulation. So the 80 is now being pumped out into the
25:31 circulation and 80 mils from my systemic has to return back to my
25:36 So it's only a small portion of total portion in your body. But
25:41 see how both sides are are pumping same amount, right? I could
25:45 said 100 mills. That would've been . But that idea, this idea
25:50 the same amount of blood is moving the heart in all four directions.
25:55 into and out of on both Right? And that doesn't refer to
26:01 total volume. It's a good Anyone else before we move on?
26:08 some anatomy. Anatomy. Yeah. right. Let's deal with the location
26:14 heart. We got some weird Alright. Uh This is located within
26:18 structure of the chest cavity called the steinem. Alright, so uh this
26:24 your thoracic cavity in the middle of thoracic cavity. Is this compartment called
26:28 media steinem? This is where it's . And the first thing I want
26:30 point out is where the tip of heart is All right. The tip
26:34 the heart is called the apex. apex points right down here and notice
26:39 it's pointing. It's pointing to your hip. Now some of you it's
26:41 be pointing to your right hip. that's such a small percentage of the
26:44 , we don't care who it But you can think, oh my
26:47 side. This is the direction which heart points. So when I think
26:52 apex I think of top of when I go to the apex of
26:55 hill right? But this is the . The pointy point of the
27:00 So that's pointing downward. What it's labeled on here is what's the base
27:04 the heart then? Well, if apex is the pointy part, the
27:08 is the flat part. The flat sits on the top. It's all
27:11 . So in our little cartoon I'm just gonna draw this, see
27:17 I can do this without changing the . So there's I knew that was
27:20 happen. All right, So there's pointing part that's apex that right there
27:25 the base. Very confusing. All . But if you know what an
27:30 is, it's pointy then the opposite the apex is the base.
27:35 two thirds of the mass of your lies to the left of the
27:38 Alright, So when you're a they told you, you know
27:42 for those of you grew up here the States and the place where you
27:44 your hand. When you put it your heart, you put it over
27:47 , didn't you? But notice this where your heart lies right underneath that
27:52 plate. But just the majority of mass sits a little bit right over
27:56 . Okay, So you're kind of ? And that you're covering your heart
28:00 you do this, putting your hand the left side. But it's really
28:04 the mass of the heart that sits mostly behind the breastplate, right?
28:10 that's where it's located in the middle your thoracic cage in the media
28:14 Alright. What covers the heart is layer of protective connective tissue called the
28:22 . Alright. The pericardium is actually double walled sac. We're going to
28:27 that there's two layers here. And this pericardial sac has within
28:31 It has fluid. So the outer nearest the surface, the the most
28:39 sorry, the most superior portion is is referred to as the fibrous
28:46 Alright, so here you can see down here is the muscle, the
28:49 , this is the chamber of the . And what they're saying here is
28:52 here. That is the fibrous And then on the side that's nearest
28:58 heart. That's the serious pericardium. together the series pericardium and the fibrous
29:05 has a space in between them that referred to as the pericardial sac.
29:09 it's in this sack where we have fluid. Now again, for those
29:13 took A and P. Two. took ap one, you know where
29:18 going here with this. Okay, gonna ask you guys. I'm looking
29:23 your faces. I know who was my class. What are we made
29:26 . Do you remember what I I said lots of times. What
29:28 we made of? Made of? on. Made of starts the letter
29:36 ends with a T. It's not hard question. What are we made
29:42 ? You remember? She's like, not gonna look at him. Were
29:46 of meat. Alright. We're made meat. Right. If Shasta came
29:54 in here? Well, she's a small. But the old Shasta before
29:57 died. If Shasta came in which I can't eat you guys,
30:00 made of vegetables. No, he look at you lick his lips and
30:05 chomping down on you because you are of meat. All right.
30:11 when we eat meat, because we're , we typically do something to the
30:16 . What do we do to the ? We cook the meat.
30:19 So, heat is usually how we meat. There are other ways to
30:22 meat, but he is the way cook meat. If we are made
30:25 meat is heat good for us. . Right? So when we rub
30:30 hands together, we create friction friction heat. And you can feel that
30:35 . All right now, is your always beating? Is it always
30:40 Yeah. Uh huh. So it's moving and it's always rubbing up against
30:46 lungs and over time, what would ? You'd produce heat and then you
30:52 your your your your muscle and that which is meat would then be a
30:56 big fat, juicy steak sitting in middle of your chest. It wouldn't
30:59 able to do what it does. we've got to stop that from
31:03 And this is where serious membranes come . They release a fluid called serious
31:08 , which is very very lubricating, reduces friction. And so what you
31:16 is basically the heart glides against the via the pericardium and the plural set
31:22 basically doesn't produce heat and that's why extend basically live your entire life without
31:27 heart turning into a cooked steak. . So what are we made of
31:35 now? Really? What is When you go to the grocery
31:37 Meat is literally muscle and the heart made of muscle. In fact,
31:44 just gonna tell you that we're not do this in the class because when
31:46 don't have a budget and two, guarantee you none of you would do
31:48 . But I have a colleague that's at a at a small college up
31:52 north texas and he teaches the lab the lecture and when he does the
31:57 , he goes out and buys a bunch of cow hearts and they do
32:00 dissection kind of looking at the pieces and afterwards he grills them and serves
32:04 heart. You like that. What his heart? It's steak with
32:10 fat. All right. Would you it? What if I didn't tell
32:17 if it was hard, What if said here's a mistake. You wouldn't
32:20 the difference. If you go and at it at stake. It just
32:23 look like it because you'd see the old cow heart thing, but I'm
32:29 gonna do it here. But I you if you haven't done it,
32:32 and do it go, you can to the one place you can really
32:35 . You can go to fiesta and can buy cow hearts. They're like
32:40 . Yeah. And then you can at the stuff if you want to
32:44 with the heart, you can go at it and then afterwards season it
32:49 it. You're looking at me like is the most shocking thing you've ever
32:54 of. It's a heart. Now , I'm with you. There are
33:01 I will not eat that come out the body. I will not eat
33:04 . No. And you guys are there arguing about a heart. Heart
33:09 a muscle, liver is not a , liver is an organ that takes
33:13 the toxins and says, you know ? I'm gonna absorb those. I'm
33:16 gonna touch that. I will not tripe. What? Yeah. All
33:21 people said norman, you know, , Sundays not gonna happen. I
33:26 not put tribe in my body. know, we all have our things
33:33 . It's muscle just like a You guys are now talking about it
33:40 no way Jose. All right. here we can see fibers. It's
33:49 dense connective tissue sits on the outside that. You're gonna see both layers
33:54 the serious membrane. So the one nearest the heart is referred to as
33:58 um Excuse me, is the visceral . The one that's furthest away from
34:04 heart of the parietal layer. And it creates what we call we call
34:07 potential space, basically the potential space already filled with fluid. So,
34:11 why it's a potential space. It's with something. All right. And
34:16 this is what prevents the heart from the friction but moving beyond the
34:21 We're gonna move down into um We basically the heart is divided into kind
34:27 three layers. So the pericardium is of the outer layers. So that
34:30 what is referred to as the epic . Um Alright, so, it's
34:34 the visceral portion of that serious Alright, So that would be the
34:40 gets closest to the heart is adhered the heart. It's part of the
34:43 . Then underlying that, that stuff actually interested in. That's the myo
34:47 um That's the muscle portion. And what we're going to see is
34:52 there's not only muscle there, but some connective tissue that serves as a
34:56 of a skeletal framework on which those can work. And then third on
35:00 inside lining the inside of all the is an epithelial layer that is contiguous
35:08 the rest of the vasculature. In words, it's an epithelium specific to
35:13 the cardiovascular system. Alright. This what is referred to as indo
35:18 We just give it a special name thallium. All right. So,
35:23 have these three layers. So, we look at the myocardial, we
35:28 see here, the fiber skeleton of heart and what we've done is we've
35:32 a cut between the atrium the Alright. So, if you can
35:37 this picture kind of here kind of it right there on the dotted
35:41 That's not exactly where it is. you can see and if you were
35:44 look from the top, looking down the ventricles. So, in this
35:47 picture right here, what you're seeing I've cut away the atrium and now
35:52 looking straight down the heart and you see here the skeletons framework.
35:57 That's connective tissue. The muscles attached that framework, and you can see
36:03 within that framework. You can see four valves. All right.
36:09 this connective tissue has four major functions we need to be aware of.
36:14 first being. It serves as a support between the atria ventricles.
36:21 It's basically the dividing line between the chambers and the lower chambers.
36:27 what it does is it provides a to which the heart valves can actually
36:34 . Alright, It needs a structure which it can be attached to and
36:39 muscles need something to pull on in for them to do their work.
36:43 so, this fibrous connective tissue in middle of the heart serves as the
36:48 to which muscles can pull on. here, you can see this kind
36:54 figure eight looking structures that's showing you direction of the muscles and how they
37:00 . Alright. You don't need to those. I mean, we'll get
37:03 that eventually. But what they do they basically ring the heart and what
37:07 doing is they're pulling on that skeleton the center, which is not
37:10 it's connective tissue and it allows that to contract to propel the blood
37:17 All right. The last thing that does is that it serves as an
37:25 , specifically an electrical insulator between the and ventricles. Because what we're gonna
37:30 in just a moment is that muscles like everywhere else in the body have
37:35 potential. So they have electrical activity them and we want the atria to
37:41 before the ventricles do and to ensure one's not influencing the other. We're
37:47 to put a barrier that prevents the signals from one side from interrupting or
37:54 the other side. All right, far. So good. Kind of
38:01 . Alright, So here we have taken a slice through the heart.
38:06 now, we're a little bit below valves and you can see that the
38:09 sides of the heart look very, different. Right? We have the
38:13 side, very, very thick muscles the right side. We have very
38:17 muscles. Now again, you can , you can go and read the
38:20 because there's everything I have up there going to tell you. But can
38:23 imagine why that would be. What I say about where blood is and
38:28 in the body. Yeah, that's right. She said the left has
38:40 work harder because there's more blood to the right side doesn't have that much
38:46 to push right now. They're not pushing all the blood. But the
38:51 you can think about this is remember is a massive blood sitting in your
38:56 system, there's a massive blood sitting your circulatory system. And what you're
39:00 is you're pushing a small volume of into that. So you have greater
39:06 in the area where you have more , right? Put another way you
39:12 to move a small box versus you to move a car, right.
39:17 one is gonna require more force to the car. Right? I
39:22 I mean, I guess if it's smart car, it's like a small
39:25 , but but the idea is it's same sort of thing, is I
39:28 to overcome the pressure, right? really the resistance of that blood.
39:35 this muscle over here on the left has to work harder to get the
39:39 amount of blood out into the systemic than the right does trying to get
39:44 blood into the pulmonary system. And as a result, the muscle is
39:49 much thicker. All right, that's we got down here now. It
39:55 shows you what's going on right right the pulmonary have low resistance, low
39:59 left side, high resistance, high . And then we come to the
40:07 oh my goodness, there's a picture the heart with lots of things that
40:11 arrows pointing at it. Okay first , don't panic when you see something
40:15 this, remember what the publisher has is they try to save money by
40:20 everything that they want to label on slide. Alright so what we're gonna
40:24 is we're gonna kind of back away kind of show you the different things
40:27 you need to know. So first what we have is we have a
40:38 . It's called the septa. We have a septa between the two
40:43 chambers. We have a septa between two lower chambers. We're going to
40:46 first. What we're doing here is focusing on there we go. On
40:51 right side. All right now the is everything you see on the right
40:54 is gonna be found on the left . Alright, so even though I
40:57 a slide over here that says left , notice it's the exact same
41:01 All right. All right, so does the septa lie? Well,
41:06 are separator. So if I have arterial septa it means it's in between
41:11 two. A tree. I said but atrial atrial septa right So basically
41:18 wall right there is the septum. and it lies between the two atrium
41:26 the ink on the slide. that's number one. And then what
41:32 wanna do? We wanna focus in solely on that right atrium? All
41:38 . Now, if you look at heart on the external side of the
41:42 which I don't have a picture It has these two little flaps that
41:45 like elephant ears, interestingly enough. called oracles. What's this called?
41:53 called an article. All right, they look like two little ears that
41:57 on the heart. Alright, so the articles, you have a little
42:03 of muscle that stands out and that called the pectoral muscle. All
42:09 Now, it's not the only place muscle is it just stands out as
42:12 unique or different. The whole structure muscle. Alright. We have a
42:16 depression right there. All right. is called the fossil. Oh,
42:22 . Now a long time ago when were a little tiny. Itsy bitsy
42:27 thing inside your mother's womb. Your didn't need to flow through all four
42:33 . Alright. It had a hole the two atria. And the idea
42:37 is you're basically moving blood flow differently you're not necessarily using your lungs.
42:45 so you're receiving blood in such a that it was bypassing the system.
42:50 , that structure is a remnant of hole in your heart to allow that
42:56 flow to flow differently. Okay, that's what that is. All
43:03 when you're a little tiny developing it's called the framing of valley,
43:08 whole the oval hole. That's what called. Isn't that funny? I
43:15 All right over here, the little little circle right there. But I
43:21 did That is called the coronary The coronary sinus is the opening from
43:27 cardiac circulation. Alright, So, gonna see the heart has its own
43:33 circle. Ization. Uh circulation. not part of the systemic circulation.
43:38 not part of the pulmonary circulation. . I said cardiac, it's coronary
43:43 . All right. Um Other things here. You can see there is
43:48 uh the inferior vena cava. That be the opening of the inferior vena
43:52 . You can't see in the But up there, that would be
43:53 the superior vena cava comes in. they basically just empty directly into the
43:59 the um atrium. Alright, And down here, race income probably should
44:06 picked a different color. Don't you here? Blue Better. Yeah.
44:15 then lastly this right here, that's right A. V valve.
44:20 Now notice everything we just talked There was in the right atrium.
44:23 didn't even look down in the ventricle . Okay, so one of the
44:27 ways to do this is say I'm gonna walk my way through the different
44:30 . I'm gonna start up here on top and I'm gonna work my way
44:33 to the bottom. Alright, I'm follow the flow of blood.
44:36 if I know what's going on in atrium? After I've done with the
44:38 , I can say thank you very . And I can move now down
44:41 my venture coal. And so I'm ventricle. There's a couple of things
44:44 I want to point out to. right. The first is the tropically
44:51 . Alright now, ridiculously, when guys learn about bone are basically the
44:57 tiny weird extensions in spongy bone, the parts that make up the kind
45:01 mesh work. So what is typically you think of mesh work?
45:07 And so if you look around the of the ventricle and just kind of
45:12 , circling in areas where there's You can see this muscle.
45:17 So it's meshed meat. That's what literally means, Right? That's that's
45:24 muscle of the heart. Okay we have these bumpy things. I'm
45:31 raise the income slide, see right right there, right there, right
45:36 . I'm gonna go to the other as well. You can see a
45:39 one right there as well. All , these are called papillary muscles.
45:44 right now the papillary muscle is attached a tendon. Alright, this tendon
45:49 called the cord attended. A And can see all the quarter 10
45:52 right there, Those quarter 10 today attached to the edges of the valve
45:59 of the A. V. And what they do is that when
46:05 ventricles contract. So the papillary muscles contract as well. What they do
46:09 they pull on the court of 10 and what they're doing is they're pulling
46:14 valve tight because when the valve or the ventricle contracts, it's creating a
46:20 bunch of pressure, more pressure to cause the aortic valve to open,
46:26 the pulmonary valve to open. But pressure is so great that if you
46:31 have these tendons, the A. valve would blow open the opposite
46:37 which is bad because you want your to flow out the other way.
46:41 , it's basically like tying ropes to end of a tint and having a
46:45 go behind your sitting there pulling it holding it in place. That's kind
46:48 what it's doing. All right. the last structure of interest right up
46:55 , that's the pulmonary semi lunar Alright? Pulmonary valve. So,
47:03 a lot of structure here in the . And really what I'm trying to
47:06 is showing you the important things that you can see or how we're going
47:11 see how this heart is actually doing it does. Okay, so back
47:17 the corner, back in the very , do I need to go over
47:24 again? Alright, so that's a just please don't go over it
47:28 Is what he said. You we're good over here. All
47:32 I like that. All right. , if we do the same thing
47:35 the left hand side, it's hard see because this is a view from
47:39 right hand side, but everything you on the right side is gonna be
47:43 on the left side. So everything this slide is just the same
47:47 but it's now pointing to the left of the heart. Okay, so
47:56 have two slides here that deal with valves again and I know we've already
48:00 about this but this is I just to reinforce. Alright, the first
48:03 I want to point out here is v valves. They're always gonna be
48:06 between the atria and the ventricles, it's not easy to lose them.
48:09 says it in the name where they're . So secondly, these valves are
48:13 ones that have the court intensity attached them, right, which are attached
48:19 the papillary muscles in the ventricles. again, the purpose of this is
48:23 ensure that the valves open in only direction, you want them to open
48:28 so that blood flows from the atria the ventricles. You don't want them
48:32 open up the wrong way so blood backwards into the atrium when the ventricles
48:37 . Alright, so they have that right, and so we're guaranteeing or
48:43 that flow occurs from the atria to ventricles? Alright, Similar valves.
48:51 . Semi lunar valves are are They have these cups um What they
48:59 , right? Is there situated in a way that they don't need um
49:06 These quarter 10 today? Alright. they're like half moons like. So
49:13 that when blood is on the so they're in the aorta or in
49:18 pulmonary trunk, the blood pushes down holds the cups in place and it's
49:24 back pressure that holds them and prevents blood from flowing down because of their
49:28 . Like they're like cups. When the ventricles contract, What that
49:35 is is they force the valves to up. I can't make my cups
49:39 that direction right? So this is to direct blood flow from the ventricles
49:45 the arteries. This is probably a picture. It kind of shows you
49:48 going on. Um You can see here it's open and then when the
49:53 are contracted, what they do is hold everything in together when it comes
49:57 the A. V. Valve. , when the semi lunar valves are
50:01 , blood is flowing outward, you see how the cups have kind of
50:04 , allowing flow outward. But when pressure and the flow wants to go
50:08 down, the blood catches in the and slams the edges shut so nothing
50:14 escape through them. Right now. don't need valves between the veins and
50:22 atrium, the atria always want to blood. And truthfully what keeps blood
50:28 flowing backwards is when the atria it actually squeezes the vena cava and
50:33 squeezes the pulmonary veins closed so that can't go backwards because they're part of
50:40 wall of the atria. Alright, they're unnecessary. So the flow of
50:46 will always be from those veins into atria through the valve because of a
50:53 gradient into the ventricle. When the contracts the valve slam shut and the
50:59 has to be relieved somehow, which the semi lunar valve to open.
51:03 it doesn't matter if you're looking at right or the left hand side of
51:05 heart. Same thing is true. matter which side you go to.
51:10 , you're trying to visualize it aren't know when I look at somebody,
51:14 always like, I'm gonna come in with silly string. I threatened every
51:20 every semester I am one of these , I'm coming with silly string.
51:24 you don't answer my questions. If don't laugh at my dad jokes,
51:33 practice, safety, safety, life to be fun. All right questions
51:46 far. Anything about what I've talked and I'm kind of talking slow,
51:49 I'm going over a lot of different . So no questions were all
51:55 You can draw it over and over . Alright. All right, coronary
52:01 . More anatomy. Where I heart is has its own little circulatory
52:07 . Alright? It's separate from the circulation, basically the opening to the
52:12 circulatory system is located just outside the valve. And so when the heart
52:19 , because remember it's a pump pump , pump. It pump. It
52:23 pushes blood up in the aorta and pressure drives blood into the coronary
52:27 The pressure in the artery does the the aorta. Alright, when the
52:32 is open, you actually block the into the coronary circulation. So this
52:37 a very short circulatory system. You see here all the arteries and veins
52:41 that have been filled with latex to you where it is and they removed
52:44 the tissue. And the other thing weird about this is that the blood
52:49 through the circulatory system in the coronary system is intermittent. Alright, It's
52:54 the heart itself where it's like, the rest of your body. What
53:00 see is that while initially blood entering the body is pulsing tile, it
53:05 smoothed out and becomes a nice um nice simple flow. Alright, so
53:12 we don't have that kind of flow there's multiple reasons behind that, but
53:16 , ultimately it's because of the pumping of the heart and the pressure going
53:20 and down over and over again. anatomy, you need to know here
53:29 the arteries, the major arteries and veins that are going to supply the
53:34 circulation. Alright. And so hopefully will make sense to you what we're
53:38 again is the anterior view of the . And so we're going to see
53:43 we have a major artery. We a left coronary and right coronary
53:46 Does that make sense to have a side and right side? Okay.
53:49 right. So you can see here coronary artery, right coronary artery from
53:54 left coronary artery, what we have we have an artery that goes right
53:58 the center between the two ventricles. . And so this is on the
54:04 hand side, so it's called the and then inter ventricular artery.
54:09 so this is what's providing blood to the muscle that's doing all the pumping
54:13 the front side of the heart and a branch of that left coronary artery
54:17 around and along the edge. Now can see it's back over here but
54:22 want you to kind of get the along the edge. So we're talking
54:25 the posterior wall of the left um . So that's how we're getting all
54:33 muscle, how it's getting, it's on the left hand side, on
54:36 right hand side. What we're gonna is we kind of go around the
54:41 side and we come along the edge the margin and so that's the right
54:47 artery and then on the backside. we do is we go down and
54:51 around the back side between the two and so posterior inter ventricular.
55:00 So the cartoon makes it really easy see it when you're looking at an
55:04 heart. You have to kind of what you're looking for. And there's
55:08 of a little indentation um that you see where the shows you the to
55:15 the inter ventricular arteries are supposed to All right. But I think four
55:20 for the front of the heart and back of the heart. Four arteries
55:24 kind of those are the generic And then when we get to the
55:30 , what we have is a very large structure that ultimately opens up
55:35 the atrium, right? And which we're going to We're we're turning deoxygenated
55:40 . So we're going to the right . It's gonna be called the coronary
55:45 . Alright, so that's on the of the heart, the posterior side
55:48 the heart. So, coming into coronary sinus, sinus, coronary
55:54 We have the great cardiac vein that's run alongside the anterior inter ventricular
56:03 We have the middle cardiac vein. , that's gonna run alongside the posterior
56:09 ventricular artery. And then we have small cardiac vein which kind of sits
56:14 over on the side and runs alongside the marginal artery is. We also
56:20 a posterior cardiac vein which is going be running alongside where the circum flex
56:25 is. And then we have the cardiac vein. Um see if I
56:32 this right. Yeah. That's not on here. That's right. I
56:34 probably read my slides. All But this also goes right into the
56:39 atrium. And so the idea here I'm returning the de oxy blood that
56:44 heart used back to the heart. the reason I need these is because
56:51 heart can't steal oxygen from the blood it's pumping. Alright. That India
56:57 serves as a barrier to the movement oxygen back and forth between it.
57:02 , it needs its own circulation to so. All right. Everything we're
57:13 see here if you remember stuff about muscles is more or less the same
57:20 . So, what is the It's muscle. It's meat. Can
57:26 cook it and eat it? Are we going to? Because we're
57:31 scared too. But we'll eat liver tripe brains, brains. Yeah.
57:40 . Just could not pay me enough even though it's mostly fat.
57:47 All right. So cardiac muscle exists in the heart. It is
57:52 Just like skeletal muscle. It is voluntary. Unlike skeletal muscle, you
57:57 make your heart do what you wanted do, right? Can't make it
58:01 faster or slower. Jason doesn't All that stuff you see in all
58:06 horror movies where they die and then come back to life because they slow
58:08 heart doesn't work. All right. made up. It's great fantasy.
58:13 right. What we have here is system that has its own internal
58:19 So, very early on in You'll actually see these cells arise before
58:24 chambers even show up and they'll begin already pulse pulsating over and over and
58:30 again. And your heart forms initially those things are. It's really cool
58:36 see. All right now you can the pacemakers through the nervous system,
58:43 ? I scare you rate gonna go . Yes, but notice it's a
58:50 through experiencing the environment. The nervous goes, oh, something's dangerous.
58:55 need to prepare myself to either fight run away. Right, So it's
59:01 response. You're not sitting there oh that person's my heart better start
59:05 faster. That didn't happen. All now, I just want to show
59:09 here, just to kind of give kind of sense of their similarities and
59:14 . Right? Skeletal muscles very, long, slender coal. Remember we
59:17 muscle as long as the muscle, name muscle itself multi nuclear. Because
59:23 cells are fusions of multiple cells. they have multiple nuclei. They don't
59:29 branches basically. They just run in straight line the entire length of the
59:33 . And lastly, they are not with each other. So each of
59:37 individual muscles are separately wrapped and separate each other. When you deal with
59:42 muscle, you have these very, short muscles. You can see right
59:46 , for example, c there's a the boundary that right there is one
59:50 cell. Alright, that right there one muscle cell. one muscle
59:54 Alright, so they're very short, fat. They're united nuclear because they
59:58 fuse. Like you saw in skeletal they are branched which is really
60:04 You can see that branching right here the middle. It's just the muscle
60:07 themselves have these branches to them and interconnected to each other. So the
60:11 is connected to that cell which is to that cell and so on.
60:16 , so they communicate with each Alright, so where these do not
60:21 with each other, These do communicate each other right now, in terms
60:25 the structure internally, they're very very . They have the T. Tubules
60:28 we described in A. M. . One. They have the Circle
60:31 in particular. Um They have mile pills. Um The filaments, they've
60:35 all of that stuff. But one the things that's unique about them is
60:38 have this structure called the inter collated . Alright, so in the
60:43 I'm gonna go back here. This pink thing that you're looking at that
60:48 an inter collated diskettes. The point contact between the two cardiac muscle
60:53 All right there like um causing them be uh you know or what allows
61:00 to be connected are a series of OEMs and gap junctions. The Dismas
61:04 hold the two cells together so that one cell contracts it pulls on the
61:08 cell right? And it has gap so that materials ions in particular can
61:17 in between the two cells so that can communicate and talk to each
61:20 So if I have a cell that's over here, the the ion movement
61:25 causes that contraction are passed on to cell over here. So even though
61:29 cell is contracting, it's telling the cell to it, you contract to
61:33 so it contracts and so you get chain reaction of contractions between all the
61:39 that are interconnected with one another. other thing and this is not shouldn't
61:45 surprising at all is you have mitochondria over the place makes up almost a
61:50 of the um the internal structure of cell. And whenever we see
61:57 that's an indicator of energy usage. ? So the more mitochondria you
62:02 the more energy you need. And kind of makes sense because your heart's
62:05 beating right? The thing is, you know this is that the heart
62:15 rhythmically. You guys noticed that you put your head on somebody and just
62:20 to their heart for a little Thump, thump, thump,
62:22 thump, thump, thump, thump and over and over again. It's
62:26 the sound is love dub. Love a BB dub with a P.
62:30 don't know, lubed up, lubed . That's how it's described.
62:34 so this rhythmic behavior is actually that you hear is really the opening closing
62:41 the valves. But that rhythmic behavior that pumping is a result of the
62:46 their heart pump is a result of muscle contracts, contracting and relaxing over
62:51 over in a very rhythmic fashion. there's two types of actual muscle
62:56 So both cardiac cells, there's actually different types here that we need to
63:01 concerned with. Now, when you of the heart, you think of
63:05 , I'll cells and it's okay to . So, 99% of the cells
63:08 the heart are what are these I'll cells. They're doing the hard
63:12 of making the heart contract and relax pump the blood in your body.
63:17 you also need cells that tell them to contract. And these are the
63:22 rhythmic cells. All right. They're referred to as nodal cells. And
63:26 the ones that have this pacemaker That's another word you can use from
63:30 pacemaker cells. Right. And they're . They have the activity to tell
63:36 the other cells when to contract. , so, about 1% of the
63:41 of cells aren't doing the heavy They're the boss cells. Okay,
63:46 where you can think about that. , I can't do anatomy physiology without
63:53 about action potentials at least once. , sorry. All right.
63:59 what I wanna do is I want remind you very, very briefly about
64:02 action potential. Remember max potential is the flow of ions in and out
64:06 a cell that creates an electrical Right? And we can use that
64:11 current for a whole bunch of different . We talked about muscles use that
64:15 current as a signal. Tell a to contract in the nervous system.
64:19 use that electrical signal to tell a neuron when to fire. Right,
64:24 guys remember that. Ok, so the electrical signal is gonna look a
64:29 different than what we've seen before. it still does the same thing.
64:33 a signal to tell a muscle cell this case it's a contract, I'll
64:38 cell when to contract, right? a cardiac muscle cell. What we're
64:45 at here in this picture and on top is what a nodal or auto
64:51 cells. Um Action potential looks like very weird looking right? Remember what
64:57 actual potential of a neuron and skeletal was went like this. I'm facing
65:03 went up and then it went down kind of did this sort of
65:06 You remember that? And look at one, it goes up kind of
65:10 down plateaus and then drops down and this weird table thing. So,
65:14 kind of looks like a table or a chair with a very, very
65:17 back. Right? You see that there's a reason why it does this
65:25 we're gonna look at that in just second here. Right. What I
65:29 to point out here, is that we looked at action potential, I
65:32 have taken a sip because my but I just want to keep
65:38 All right. When we look at potentials previously, we said there were
65:42 ions involved. You can't remember what two ions were sodium and potassium.
65:47 . Alright. So, what we're now is we're just adding one
65:51 We're adding calcium. Alright, when was present, that caused deep
65:57 When potassium was present, it caused or re polarization. Remember that?
66:02 , if you think of the action going up, that's deep polarization when
66:05 comes back down, that would be polarization. And then so on this
66:09 that sodium and then on this side was potassium. Remember that. And
66:14 you don't it's like, okay, know where to go looking for
66:17 All right. So, here, kind of gonna be the same
66:19 We're gonna see three ions. We're see the sodium and potassium. It's
66:24 gonna do anything differently. But then have this weird one, calcium and
66:27 does something to make that weird All right. And so I'm just
66:31 flip to the next slide just so you can see so deep polarization.
66:35 So, at rest we're at a point of rest and this is gonna
66:38 the function of open potassium channels. care about that so much what I
66:43 you to be aware of is the polarization. Alright, so deep
66:48 Is this right this right there that's function of the opening of voltage gated
66:56 channels. Oh you mean just like we learn the actual potential before?
67:00 , exactly. So deep polarization is function of sodium and then those channels
67:05 and they close and when they close can see right there that it's like
67:10 we're gonna start re polarizing. But else happens. And that's this
67:16 That plateau is a function of two . First, the opening of the
67:21 channels, they're like all right let's let's go down. We're gonna re
67:24 and then the calcium channels up and no, no, no, not
67:28 . And what they're gonna do is gonna sustain a deep polarized state for
67:32 period of time and then I'm gonna up that calcium channel and then I'm
67:35 return back down like. So so easy way to think about this.
67:43 , easy is always better than every aspect psyllium causes it to de
67:49 calcium causes it to plateau potassium causes to re polarize. So you see
67:56 table, right? So if you draw it out, you could say
68:01 calcium potassium right, sodium calcium That's the easy mode. Alright.
68:13 the reason we do this, why we need something so weird like
68:19 It has to do with refractory Refractory periods. I remember that
68:24 Do you remember that word? A period. Remember is a period of
68:29 in which you can't get another action . Right? So why do we
68:35 this refractory period here? Because we to create pulse, it'll activity of
68:41 heart. We want to create rhythmic . We want a period of time
68:45 we're going through contraction and relaxation and don't want the heart to contract and
68:50 contracted. Well, good on I don't want a contract at
68:56 That would be bad. Right? if you look at this picture up
69:00 at the top that skeletal muscle and can see in the little green that
69:05 green represents the action potential and the on that action potential. The blue
69:10 really actually little green represents the refractory in that action potential. Remember an
69:18 potential is not a contraction and potential signal to cause a contraction. And
69:22 we see in that top picture up is we see the action potential.
69:25 refractory period. But right afterwards we the contraction. Right? And if
69:31 do a whole series of action really, really quickly, what we
69:34 do is we can create a series contractions that cause tetanus and that's where
69:38 get that contracted muscle. Right? all remember that the last thing we
69:43 about in the empty one. Alright , the refractory period is sustained because
69:52 the presence of that calcium. That's the bottom graph is showing you.
69:57 so you can see deep polarization boot . I go and then calcium is
70:01 and that causes that plateau and I bring down that action potential or reset
70:06 until the calcium is gone. And what I end up with is this
70:11 of time where I can't get another potential. But remember it's that deep
70:16 that causes the contraction and the red here that little bump. That's the
70:24 of the muscle fiber. So I an action potential. I get contraction
70:28 relaxation and then I get the muscle end of the action potential. So
70:34 contraction takes place throughout the entire refractory . So what does the heart do
70:38 it beats it beats? Think about you see someone cute. All I've
70:50 is I've decreased the amount of time each of those action potentials. But
70:53 still allow the heart to go through contraction and relaxation phase. It will
70:58 go into a sustained tetanus because of peak or that plateau. So good
71:07 that. Does that make sense? this is for the auto rhythmic
71:12 Right. They're the ones that tell the other cells what to do.
71:15 tell it? Fire? Fire. the contract. I'll cells are contracting
71:21 response to that signal that these guys producing. I'm sorry. Back it
71:27 , raise what I just said one . These are the I said auto
71:31 cells. These are the contract. cells would make sense because they're causing
71:34 contraction golly. It's been a long already. Alright. What we're gonna
71:41 at now is how do we get signal to the contract? I'll
71:44 We're gonna see what the auto rhythmic action potential looks like. And that's
71:49 the next two slides are. And we'll be done for the day or
71:52 slides. Alright, so this is a pacemaker action potential looks like.
71:58 . It's very very different, isn't ? It looks a little bit more
72:01 the first type of action potential. learned a long time ago, but
72:05 still not the same what we Is there's really no resting period,
72:09 there? It's like you've got this of time where you slowly contract and
72:14 get this peak and then deep rollers re polarization. You hit this low
72:19 and then you start climbing again. right. So, the auto rhythmic
72:26 are self signaling there, causing themselves naturally de polarize. And it's a
72:33 again of the three ions. We at sodium calcium and potassium.
72:38 Whenever you see potassium just presume de or re polarization or hyper polarization?
72:43 see sodium consider you're doing deep polarization this case calcium also causes deep
72:49 It didn't the last one. But doesn't look like deep polarization. Because
72:52 got a plateau. Alright, But we have here, we have different
72:56 of channels and they all play an role to cause this to happen.
73:01 right. So, we have these . F. Channels. Now
73:04 F. Stands for funny channels. right. There. It's inward.
73:08 . That's their name. Very Alright. So, what we're going
73:14 see here is how this thing So, the resting potential again,
73:19 60 minus 16 minus 70. Um don't really have this sustained period.
73:25 is all going to be a result the sodium potassium A. T.
73:29 . A. The sodium leak channel channels that are available. So that's
73:33 you where you are in terms of your rest is. But really this
73:37 your rest. Right. Right, , right there. That that's how
73:40 it is. And what happens is you hit that rest, that's gonna
73:44 sodium to start coming into the Because there's leak channels already there.
73:49 , see if you have sodium channel channels, sodium comes in and sell
73:52 happening to your your cell? Is D polarizing polarizing? Hyper polarizing.
73:57 d polarizing. So you're getting this deep polarization and that slow deep polarization
74:03 the opening of these funny channels? . Funny channels or sodium channels.
74:09 I open up some sodium channels. now what happens more sodium comes in
74:13 more sodium comes in. Do I polarize faster or slower faster?
74:19 Right. If I'm D polarizing And I open up more channels,
74:23 gonna start d polarizing faster. Look what our curve does. Is it
74:28 like this or is it going like ? It's kind of going kind of
74:32 this. And so as more sodium in it causes the opening of the
74:37 type of calcium channel. The first of calcium channels are the T.
74:41 . They're called transient. That's where tea comes from. And so that
74:45 calcium to flow in. That causes to move even faster. So you're
74:49 starting off like this and then you curving upward as a result of the
74:54 than the calcium. And then at certain point what we call threshold.
75:02 when we open up the L. the L. Type calcium channels open
75:09 at a specific time. It's really a specific vulture but a specific
75:13 And they open up and that causes massive deep polarization event. So what
75:18 seeing here, that's a function of . So down here sodium and calcium
75:29 , calcium and then all those things shut. And then we're going to
75:34 in the next stage the following That's when you slam the calcium channels
75:39 potassium channels open and you de And then when those channels close,
75:44 rinse and repeat the whole process comes over again. So when you're dealing
75:48 these auto rhythmic cells. What are doing? Slow, deep polarization
75:53 Deep polarization, massive deep polarization, polarization, slow deep polarization, faster
75:59 polarization, massive deep polarization. And they're doing is they're creating a signal
76:05 is then transferred over to those contract cells and that signal says fire.
76:11 they released their sodium. That caused to go up calcium, peak potassium
76:17 down. And then what do the I'll sell do as a response to
76:20 action potential contract, relax. So is your heart doing, bump,
76:27 , bump, bump? You guys right. Woo hoo. So we've
76:33 through our first thing when we come , we're gonna talk about more about
76:35 heart. And then the last two are going to be about the
76:41 No questions, of course, because
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