**Anatomy of the Heart and Coronary Circulation — Transcript & Summary | SozAI**
Source: https://sozai.app/transcript/heart-anatomy-coronary-circulation/

Ninja Nerd's anatomy lesson on the heart and coronary circulation, covering heart wall layers, chambers, valves, and coronary arteries using illustrations and an Anatomage table.

## Key Takeaways

- The heart wall has distinct layers, each with specific protective, lubricating, or contractile functions
- Pericardial fluid enables smooth gliding of the heart surfaces during each cardiac cycle
- The coronary arteries supply the myocardium, and their anatomy is important for understanding ischemia and infarction
- Knowing normal anatomy helps in recognizing pathology

## What the video covers

- Introduces learning the anatomy of the heart and coronary circulation using both illustrations and a 3D cadaver on an Anatomage table
- Walks through the layers of the heart wall from superficial to deep: fibrous pericardium, serous pericardium (parietal and visceral layers), myocardium, and endocardium
- Explains the functions of the fibrous pericardium: protection, anchoring the heart, and limiting overfilling
- Describes pericardial fluid in the pericardial cavity that reduces friction during contraction and relaxation
- Covers the myocardium as cardiac muscle responsible for heart contraction and blood expulsion
- Examines the endocardium, which lines the chambers, valves, and continues into the great arteries
- Reviews the right atrium, interatrial septum, and fossa ovalis as a remnant of the foramen ovale
- Discusses internal ventricular structures such as the moderator band and anterior and posterior papillary muscles
- Covers the coronary arteries, including the right coronary artery, marginal arteries, and the artery supplying the SA node
- Explains coronary veins such as the great cardiac vein and the clinical relevance of referred pain in myocardial infarction

## Chapters

1. 00:00 Introduction and Learning Approach
2. 03:18 Layers of the Heart Wall
3. 07:00 Interior of the Right Atrium and Septal Anatomy
4. 14:22 Ventricular Structures and Papillary Muscles
5. 24:06 Coronary Arteries and Blood Supply
6. 33:50 Coronary Veins and Clinical Correlations
7. 44:40 Conduction System and Coronary Ostia

Answers

## Questions about this video

What are the layers of the heart wall from superficial to deep?

The video describes the fibrous pericardium, the parietal layer of the serous pericardium, the pericardial cavity with pericardial fluid, the visceral layer of the serous pericardium (epicardium), the myocardium, and the endocardium. Each layer has a distinct structure and function.

What is the function of pericardial fluid?

Pericardial fluid sits in the pericardial cavity between the parietal and visceral serous layers. It reduces friction so the layers can glide smoothly as the heart contracts and relaxes, preventing inflammation.

Which coronary artery supplies the SA node?

The sinoatrial (SA) node, the heart's pacemaker, is supplied by the sinoatrial nodal branch, which is typically a branch of the right coronary artery. The video emphasizes this as important knowledge for exams.

## Full Transcript — Download SRT & Markdown

00:08

Speaker A

What's up, ninja nerds? In this video today, we're going to be talking about the anatomy of the heart and the coronary circulation. Again, we'll be talking about this utilizing two different ways of learning. One is we'll be going through our illustrations, going step by step, having a great learning process, but also we'll dig into our three-dimensional cadaver and use our Anatomage table to help us navigate through that, as though we're kind of a little red blood cell moving along the way through the heart.

00:18

Speaker A

step by step having a great learning process but also we'll dig into our three-dimensional cadaavver and use our anatomage table to help us to navigate through that as though we're kind of a little red blood cell moving along way

00:29

Speaker A

So let's actually go ahead and dig into the illustrations, and after that, let's go ahead and dig into the heart and then start actually talking about every single piece, going through, identifying things, and pretending we're a little red blood cell moving along the way.

00:42

Speaker A

moving along the way. All right. So, let's talk now about the anatomy of the heart, the coronary circulation. We'll dig into this, go through the illustration step by step, and then we'll kind of review with just an overall kind of like view um looking at

00:53

Speaker A

All right. So, let's talk now about the anatomy of the heart, the coronary circulation. We'll dig into this, go through the illustration step by step, and then we'll kind of review with just an overall view looking at the Anatomage table. So, let's kind of step into this.

01:02

Speaker A

you imagine I have like a knife and I'm going to penetrate it through the person's chest wall, and I want to talk about what layer the knife is going through from superficial to deep um sequentially. And so you can imagine

01:12

Speaker A

So, first things first, I want to take a look at the actual heart wall. So, I want you guys to think about this in a slightly morbid way, but imagine I have a knife and I'm going to penetrate it through the person's chest wall, and I want to talk about what layer the knife is going through, from superficial to deep, sequentially. And so you can imagine that by just zooming in on this whole heart wall layer. And we're going to go through this from superficial to deep.

01:19

Speaker A

The first layer that we have highlighted is the fibrous paricardium of the heart. Really dense irregular connective tissue. When we think about this, what is the overall function? Well, if you can imagine, because it's super hearty, it's going to protect the heart from a

01:33

Speaker A

The first layer that we have highlighted is the fibrous pericardium of the heart. Really dense irregular connective tissue. When we think about this, what is the overall function? Well, if you can imagine, because it's super hearty, it's going to protect the heart from a lot of external forces. And on top of that, since it's a really strong connective tissue, it can anchor the heart down to the surrounding structures associated with it. Another thing is that because it's a little bit more rigid, we don't want the heart to always overfill. And so this is only going to allow for a certain degree of stretch, if you will, and it's going to prevent that heart from overfilling with blood. So three primary functions: again, protect it, anchor it, and prevent it from overfilling with blood.

01:45

Speaker A

more rigid, we don't want the heart to always overfill. And so this is going to only allow for a certain degree of stretch, if you will, and it's going to prevent that heart from overfilling with blood. So three primary functions is

01:56

Speaker A

The next one, just deep to that, is called the serous pericardium. So you have the fibrous pericardium, and then you have another layer called the serous pericardium, and there's a parietal layer, and then we'll talk a little bit later about the visceral layer. So the parietal layer of the serous pericardium is kind of like mesothelial tissue. It's a simple squamous epithelial tissue with a little bit of areolar or connective tissue, and so it lines that inner surface of the fibrous pericardium. Some of those cells are responsible for producing the pericardial fluid that lies within the pericardial cavity that we have highlighted here in blue. The pericardial cavity holds what's called pericardial fluid. Whenever the heart contracts and relaxes, we don't want those two layers, the parietal layer and the visceral layer, to rub up against one another and get kind of inflamed, so we allow for them to have some fluid there to allow them to glide easily and keep it really smooth.

02:09

Speaker A

paricardium and there's a parietal layer and then we'll talk a little bit later there's a visceral layer. So the parietal layer of the cirrus paricardium is kind of like a meothelial tissue.

02:18

Speaker A

The next one, just deep to that, is called the visceral layer of the serous pericardium. You can appreciate it in this pinkish color, and we also give it another terminology, as you see here, called the epicardium. All right? Meaning it just clings to the outer wall of the actual heart tissue itself. Now, the visceral layer of the serous pericardium again lines that surface of the heart, and those cells are responsible for producing some of that pericardial fluid, which again allows for that gliding of the heart.

02:33

Speaker A

that we have here highlighted in blue. The paricardial cavity holds on to what's called paricardial fluid. And that paricardial fluid basically whenever the heart contracts and relaxes we don't want those two layers the parietal layer and the visceral layer to

02:46

Speaker A

All right. The next one is the myocardium. The myocardium is a thick tissue made of cardiac muscle, and that cardiac muscle is critical to the contraction of the heart. So it's obviously responsible for being able to expel blood out of the heart. It's critical to contraction and relaxation of the heart, which helps us either move blood out of the heart or relax to allow us to fill, or have a proper venous return as well.

02:57

Speaker A

is called the visceral layer of the cirrus paricardium. You can appreciate in this pinkish color and we also give it another terminology as you see here called the epicardium. All right?

03:06

Speaker A

Then we come to the innermost layer, called the endocardium. It's an endothelial tissue, so it's simple squamous epithelial tissue with a little bit of loose connective tissue, and it lines the walls of the heart. It lines the atria, lines the ventricles, and believe it or not, it even lines the valves, so it's a very important structure. And it's continuous. One of the beautiful things is that this continues into the arteries, the pulmonary artery and the aorta. It's a pretty cool thing to talk about.

03:18

Speaker A

producing some of that paricardial fluid and that's going to again allow for that gliding of the heart. All right. The next one is the mocardium. The myioardium is a thick tissue made of cardiac muscle and that cardiac muscle

03:31

Speaker A

So we can appreciate the layers of the heart wall. Again, to go from superficial to deep, which ones are they? The fibrous pericardium, the parietal layer of the serous pericardium, the pericardial cavity, the visceral layer of the serous pericardium, the myocardium, the endocardium, and then you're into the actual cavities of the heart. In this case, this would be like the left ventricle. All right, that's what I want you to take away from this.

03:45

Speaker A

or to relax to allow for us to fill or have a proper venus return as well. All right. Then we come to the most inner layer called the endocardium. So it's an endothelial tissue and so it's just simple squamus epithelial tissue, a

04:00

Speaker A

Okay, now that we've talked about the layers of the heart, let's actually go through step by step, and as one of the team members here who helps make this, get into the chamber of secrets. All right, that is the left atrium, the right atrium, the right ventricle, the left ventricle, and go through some specific structures you could have to identify on the exam. So, the first one we'll do is take an overall holistic view of the right atrium. You can see the right atrium here, and there's a structure called the auricle, the right auricle, that sits over it. Let's take and slice it open and take a better look at it to appreciate some definitive structures. We peel that right atrial auricle back. All right, we can appreciate a couple of different things.

04:12

Speaker A

of the beautiful things is that this continues into the arteries, the pulmonary artery and the aorta. So it's a pretty cool thing that we can talk about with this. So we can appreciate the layers of the heart wall. So again

04:22

Speaker A

What are those things? Well, one thing is you have three things that empty into the right atrium, bringing deoxygenated blood back to the right side of the heart. The first is the superior vena cava, which we'll talk about later. It brings deoxygenated blood from above the diaphragm. All right, that's one. The next is the inferior vena cava, which empties into the right atrium, bringing deoxygenated blood from structures below the diaphragm. And then there's another one, sometimes called the opening or ostium of the coronary sinus, which is right here, and it brings deoxygenated blood from the myocardium. So three areas of deoxygenated blood empty into the right atrium: the superior and inferior vena cava and that ostium, or opening, of the coronary sinus.

04:38

Speaker A

case, this would be like the left ventricle. All right, that's what I want you to take away from this. Okay, now that we talked about the layers of the heart, let's actually go through step by step and as one of the team members here

04:50

Speaker A

Another structure we have here is called the fossa ovalis. You might remember this is kind of a scar tissue remnant. It is the result of something in a pediatric patient that exists called the foramen ovale. That was a hole that allowed blood to shunt between the atria. We know this because when the baby is in these stages where it's growing, it's not breathing air. The lungs are within the amniotic fluid, so there's no ability to breathe air. We need that shunting structure so we can move blood from the right side of the heart, much of it, to the left side of the heart, so we can send it out to the systemic circulation and to the placenta for the placenta to do its function. But eventually that has to close off. We don't want it to be patent, so it becomes what's called the fossa ovalis, which is a

05:02

Speaker A

that we'll do is we'll take an overall kind of holistic view of the right atrium. And again, you can see the right atrium here. And you can see that there's a structure here called the oracle, the right oracle that kind of

05:12

Speaker A

sits over it. Let's kind of take and slice it open and take a better look at it to appreciate some definitive structures. And we kind of peel that right atrial muffin cap back blue. All right, we can appreciate a couple

05:24

Speaker A

different things. What are those things? Well, one thing is you have three things that empty into the right atrium. So, they bring de oxygenated blood back to the right side of the heart. That is the superior venne cable. We'll talk later.

05:37

Speaker A

Uh brings blood from deoxxygenated blood from above the diaphragm. All right, that's one. The next one is the inferior vennea. That's going to empty into the right atrium. is bringing blood, deoxxygenated blood from structures below the diaphragm. And then there's

05:53

Speaker A

another one and you can sometimes call it the opening or the osteium of the coronary sinus, but that's going to be right here and that's going to be bringing de oxygenated blood from the myioardium. So three areas of of blood

06:06

Speaker A

and deoxxygenated blood are going to empty into the right atrium. That is the superior inferior vennea and that osteium or opening of the coronary sinus. Another structure that we have here is called the foss valus. You might remember this is kind of a scar tissue

06:20

Speaker A

remnant. That is the result of something in a pediatric patient that exists called the fammen oval. And that was a hole that allowed for blood to be able to shunt between atria. And again, we know this because whenever the baby is

06:36

Speaker A

in these stages um where it's growing, it's not breathing in air. And so the lungs, they're kind of like within the amniotic fluid, right? So there's no ability to breathe air. So we need to have that shunting structure um so that

06:49

Speaker A

we can move blood from the right side of the heart as much of it to the left side of the heart so we can send it out to the systemic circulation to the placenta for the placenta to do that function.

06:58

Speaker A

But eventually that has to close off. We don't want it to be patent. So it becomes what's called the fossa oval which is a nice scar tissue between them. Um and generally that's within a structure called the interatrial septum.

07:10

Speaker A

There's usually a hole during the normal kind of developmental process that should close and become a fibrous remnant when you get older. You don't want that to stay open. The next thing is we have if we peeled that muffin cap back blue, we got

07:26

Speaker A

this kind of like part of the wall. It's more of the anterior wall of the right atrium and it's made up of a muscle called the pectinate muscles. They may play a role a little bit with kind of

07:35

Speaker A

like overall helping with expansion and increasing the size maybe of the right atrium. Uh but it's more just an anatomical structure that you may have to identify in the exam. And then there's kind of like this separation point that you may see here called the

07:49

Speaker A

crista terminalis. And that's just one of those demarcation points that we may see and you may have to identify. All right. Another thing is again you're kind of you saw it from that first view which you saw this kind of structure

08:01

Speaker A

sitting over on top of the right atrium and that is called the right oracle and we can appreciate that structure as well. It's just more of a fatty kind of tissue. All right, that is the right atrium. So we can appreciate the right

08:14

Speaker A

atrium and the structures that are kind of there. And the reason why we kind of talked about them in great detail is because whenever a patient has path, you know, pathological processes that occur such as right heart failure or they have

08:27

Speaker A

some type of issue where they have a patent famino valley. Uh those things are critical to know how these things normally function their normal structure because whenever there's a breakdown in that normal structure, a breakdown in that normal function, that's when we see

08:40

Speaker A

things like pathology. Um and so it's really really critical to know that to just give you an example if you could imagine that the right atrium couldn't receive blood from the superior and inferior vennea what would happen and we

08:53

Speaker A

see this in right heart failure blood would back up and it would cause jugular venus distension it would back down the inferior vennea and that would cause more of that lower extremity edema hpatomegaly maybe even ascites and so

09:05

Speaker A

that's why it's critical if we didn't close off that fosso valalis and it remained patent you would end up with an asyanotic heart defect and these babies they may experience severe hypoxia um and other complications as well. So

09:19

Speaker A

that's why it's important to talk about it. Let's then move down because we know that the right atrium is connected to the right ventricle but it's usually via a space which we have a valve to prevent backflow and we'll talk about that valve

09:32

Speaker A

in a second and that's called your tricuspid valve. Right? But we're going to enter our way into the right ventricle through that tricuspid valve.

09:39

Speaker A

Let's kind of open it up and take a better appreciation. So, you can see here we got a couple different things that we need to talk about. The first one is all of these kind of rigid kind of like bundled up pieces of muscle and

09:52

Speaker A

they're all over the place, but it's called the ticula carne. They tend to be they can be in all of the walls, but if you ever open up a heart and a model or a true cadaabver, you'll see and

10:02

Speaker A

appreciate it more in the anterior portion of that ventricle. But either way, it's more of these obvious kind of like rigid spindly type of muscle fibers that are presented there. All right, the next thing is we have another kind of

10:15

Speaker A

like muscle tissue that's kind of critical because the perkingi fibers actually run through this and it acts as kind of a way of being able to connect some of the papillary muscles so that they can receive that proper perkingi

10:26

Speaker A

signal and that's called the septto marginal tbacula. I like to call it the moderator band, but you can appreciate that here. And it's really just kind of like you can see how it kind of acts as like a little kind of bridging point

10:38

Speaker A

between the papillary muscles and the perkingi fiber should run through there. Another structure kind of just knowing it in general um we have what's called the pulmonary trunk and it's not to be confused with kind of like an area where

10:50

Speaker A

blood is getting ready. It's kind of like a little it's like it's moving onto a deck essentially that's going to then move through these like little valves and then go into the pulmonary trunk.

10:58

Speaker A

This little area here, this little deck if you will, is called the conis arteriosis. All right, but then again, we'll talk about this later. It kind of provides the gateway of moving towards the pulmonary trunk through the pulmonary semi lunar valve. Another

11:13

Speaker A

thing is we have papillary muscles and we have a bunch of them. This is a little overkill, but I still think it's important especially when you start getting into infarks. Whenever you have infarks, different areas control different papillary muscles, so

11:25

Speaker A

different parts of the heart wall. And so if you have for example uh an an infarction somewhere along the in the septum or on the lateral wall, it may affect those papillary muscles which then may cause particular valvular

11:38

Speaker A

insufficiencies. And again, we'll get into that a little bit later. But papillary muscles, let's kind of identify them. The first one is called the anterior papillary muscles. And then you have the posterior papillary muscles right here. So imagine these are just

11:53

Speaker A

coming out the anteriors a little bit more. And then going deeper, if you're going and punching into the actual camera, um you're going to have the posterior papillary muscles. They're going to be deeper into that right ventricle. And then you can imagine

12:04

Speaker A

here's the septum. So what would you imagine these are? That's the septal papillary muscles. So these are your papillary muscles. And their job is to be able to contract and kind of tighten up these little strings um that are

12:16

Speaker A

called what? The cord tendon. And the cord tendon is basically a very critical structure that whenever it kind of what it does is it connects to what's called your valve cusps um or the leaflets if you will. And what happens is the

12:31

Speaker A

cordate tendon if they are kind of pulled taut by the papillary muscles they really help those valve cusp to kind of like approximate together nicely so that you get a good closure of that valve. So if a papillary muscle is

12:44

Speaker A

infarcted or it dies it can't contract. it can't hold the cord a tendon taut and then those valve leaflets or cusp are more mobile and this can cause things like regurgitation or prolapse of that structure into the appro the appropriate

12:59

Speaker A

atrium. So that's why it's important to know that. But again papillary muscles connect to the cordate tendon which are then kind of anchoring down specific cusps if you will. It's harder to point these out so but I'm going to use this

13:12

Speaker A

as an understanding here that here's our anterior cusp. It's really just this portion here. These we already pointed out are the cordate tendon but they're connecting to that anterior cusp. And then you have another one. This is called your posterior cusp. And that's

13:24

Speaker A

again it's going to be connecting to the cordate tendon which connect to the posterior papillary muscles. And then you have your septal cusps which are connecting to the cordate tendon which are connecting to the septal papillary muscles. So again you can appreciate all

13:36

Speaker A

of these structures and how they make up a really profound valvular apparatus. With that we talked about the right ventricle. We covered the valvular apparatus. We covered the tubicular carnea, the conis arteriosis, which are I think the big things to really

13:51

Speaker A

identify. All right, let's now kind of take and turn around and get into the left atrium. When we kind of open up the left atrium, peel that muffin cap back blue, you can appreciate at least some important structures that are critical

14:04

Speaker A

to knowing that way if there is disease, you can understand kind of again the normal anatomy, normal physiology. If you break it down, what the pathology may look like. All right. So the first thing that I want you guys to identify

14:16

Speaker A

is again it's the same concept. It's just it's homologous to the right atrium. If you peeled it back there's a muscle in the anterior wall called the pectinate muscles. This is just musculi pectinade which is again it's a more

14:28

Speaker A

fancy way of saying pectinate muscles but again it's the same concept same structure same function. What I want you to remember is if I remove that we can get a better appreciation for things that empty into the left atrium. So if

14:40

Speaker A

you guys remember what were the structures that emptied into the right atrium, the super vennea, inferior vennea, coronary sinus. What empties into the left atrium? The pulmonary veins. If I asked you to take a next step, how many? I want you to say four.

14:52

Speaker A

Two from the right and two from the left. All right, these empty in to the left atrium. They're supposed to bring oxygenated blood back to the left atrium. All right, really important that you know that. Now there's another

15:06

Speaker A

structure which we can kind of appreciate here and it was a hole that was actually between the right atrium and the left atrium when you were a very small baby in your mother's womb. What was that called? The famino valley. When

15:18

Speaker A

you're born it should close up become a fibrous remnant called the fossa ovalis. You're just appreciating it on the other side of that interatrial septum. Again, we see the mitro valve apparatus kind of parts of it and we'll get in we'll talk

15:32

Speaker A

about the anterior and the posterior cusps because the tricuspid valve had three cusp. This one's only going to have two cusps. Another name for the mitro valve is called the bicuspit valve. All right. And then we have what's called the left oracle. And the

15:43

Speaker A

reason why I want to mention the left oracles is the left oracle has a small little space in it called the left atrial appendage. And this is something that's important to know because what happens is in patients who suffer from

15:54

Speaker A

something called atrial fibrillation where their heart atria isn't contracting very properly. It's kind of actually shivering or quivering if you want to kind of say it like that. It doesn't get a good atrial kick. What happens is because of that it gets

16:08

Speaker A

stagnation. It gets stasis of blood and it tends to sit right here in this like little pocket. And if blood sits for a long time it can form a thrombus. And that thrombus that forms there can then get flicked off. So left atrial thrombi

16:22

Speaker A

and atrial fibrillation they they actually love to sit here. And so sometimes what we may do is if we'll put them on anti-coagulants, but sometimes if we can't or they're not responding well, we may actually have to olude that

16:33

Speaker A

space so that they can actually allow thrombi to form there. So that's why I wanted to mention that one. All right, that's our left atrium. The big things that we wanted to hit there was that left atrial appendage and the pulmonary

16:45

Speaker A

veins. seeing the other side of that fossa ovalis and then you're kind of seeing the entryway via the mitro valve.

16:52

Speaker A

But let's now move into the bottom part where we're going to move from the left atrium if we could imagine we're a little red blood cell. We're moving down from the left atrium at the left ventricle through the bicuspid through

17:02

Speaker A

the mitro valve one of those two into the left ventricle. We take a piece off and we can see inside. You can again appreciate some of those rigidy spindly structures called the trapicle carne.

17:16

Speaker A

Right? You can also appreciate your papillary muscles. If you can imagine this is the anterior. This side is the anterior portion of that heart. And this is the posterior portion of the heart.

17:26

Speaker A

You're just looking at it from kind of a lateral view. All right. So here's going to be the anterior papillary muscle. And what would this one be? The posterior papillary muscle. And we can appreciate that these are controlled by different

17:39

Speaker A

blood circuits. And we'll kind of get into that more in the kind of arterial distribution, but I want you to talk about that more in the pathology section. So when we get into myioardial inffections, it's kind of critical

17:51

Speaker A

because again papillary muscle rupture is a pretty nasty thing and it can cause a lot of mitro valve regurgitation, acute heart failures. So it's why it's important to kind of remember that. All right. Nonetheless, these are two structures that are going to be holding

18:06

Speaker A

on to what that cord tendon which are then connected to the valve cusp or leaflets. And you should have an anterior cusp which again you're kind of appreciating the top part of it. This is the cordate tendon and then what's this

18:19

Speaker A

one? This is the posterior cusp and it's just this portion here. It's connected via the cordate tendon to the papillary muscles that makes up your valvular apparatus.

18:29

Speaker A

All right, that really gets you, I think, the big things that you need to know about the left ventricle. And then we've covered the chamber of secrets.

18:37

Speaker A

Let's now move into the next part here. The next thing I want us to discuss is the valves. The valves are really important. And you're probably like, didn't we already kind of do that? Yes, we did. But we didn't really talk about

18:48

Speaker A

two other valves that I want to talk about for a second. So, if I'm taking a slice of the heart, so again, you can kind of appreciate if I'm kind of taking a slice through the heart. I'm going to

18:58

Speaker A

try and get all four valves in one view. So, we're going to do that now. And we're going to appreciate we're looking from like the top down at these valves.

19:06

Speaker A

Um, and there are some critical things to talk about. So, the first one is the tricuspid valve. And you can appreciate the three cusps, right? As we talked about the anterior, the posterior, and the septal. Then we have the bicuspit or

19:19

Speaker A

the mitro valve. and it just has the anterior and the posterior cusp. Then the semi lunar valves. So we didn't talk about these, but if you can imagine, we kind of saw the pulmonary simile lunar valve when we were looking from the

19:33

Speaker A

right ventricle up through the conus arteriosis. It's hard to see the aortic similuna valve, but it's tucked deeper and a little bit more posteriorly into the left ventricle. But again, nonetheless, they're going to be the entryways into the arteries, the aorta

19:47

Speaker A

and the pulmonary artery. So we have to have valves to prevent that back flow.

19:51

Speaker A

And so what will we have? Well, the first one is the aortic semile lunar valve. And this is going to have three of those cusps. And then the pulmonary semile lunar valve, which is going to have three of those cusps. One thing I

20:02

Speaker A

think that's critical to remember about valves in general, is that they're preventing backflow. AV valves, which are also referred to as your atrio ventricular valves, which are which ones? Your tricuspid and your bicuspid, those prevent back flow into the atria.

20:17

Speaker A

That's their job. It's not to promote flow into direction. That happens passively. Their job is that whenever the papillary muscles contract, they pull the cord tendon. The cordate tendon bring the cusp closer together that you don't push blood back into the area that

20:32

Speaker A

it just came from. Same thing. Semile lunar valves, which you can appreciate here, their job is they're going to open up whenever the heart goes into cy. The pressure gradients will push blood from the ventricles into the arteries. But

20:46

Speaker A

there will be a drop in pressure during diastily where it'll want to flow back.

20:50

Speaker A

We don't want that to backflow into the ventricles and that's the purpose of these valves. Another beautiful thing that you can see here and I love from this diagram is that off of the pulmonary artery uh at least the

21:02

Speaker A

pulmonary trunk, it'll bifrocate into the right and left pulmonary artery. The aorta itself, which is going to come after the aortic valve, it's going to then have a couple different things.

21:12

Speaker A

One, it is will move up via the aortic arch. But there's also two branches that come right off of the base of the aorta and they're very important to talk about because we're going to move into this next and that is your coronary arteries.

21:26

Speaker A

These are the structures that supply oxygenated blood to the myocardium which we need. The myioardium is such a hungry workhorse. It needs oxygen. It needs nutrients to be able to perform its job.

21:37

Speaker A

So we need to give it its own blood supply. And the same way your biceps, your triceps, your quadriceps, your brain, your all these other organs are depending upon systemic blood flow from the aorta, so is the myioardium. So you

21:49

Speaker A

can appreciate that these are just right off the base. And so they get a good amount of blood flow that moves into them. And here's a question that you'll probably be asked when during diastily during relaxation of the heart. So

22:00

Speaker A

whenever blood gets pushed out into the aorta, the heart relaxes and it creates a pressure gradient that wants to cause the blood to move backwards towards the ventricles. what should close the AV the semile lunar valves. When they close,

22:12

Speaker A

blood is then redirected into the right and left coronary artery. So that's why it's important. All right. So with that being said, let's kind of talk a little bit about more of this blood flow. And we're going to talk about it in two

22:24

Speaker A

different ways. We may have a couple other views, but we're gonna be able to appreciate a lot in the sternocostal view. This is the normal way that you would look at the heart. If I was looking at a person in front of me, this

22:34

Speaker A

is generally the way that the heart is. It's usually kind of sitting within the mediainum and it's it's shifted 2/3 to the left of the midline of that sternum and we can appreciate the apex and we can appreciate the base. This is looking

22:48

Speaker A

at it more in a dorsal kind of codle view. And so you're looking at the heart. I'd be looking at a person from the back and I'd be able to appreciate that this is what it would kind of look

22:57

Speaker A

like from the back where it's shifted two/irds to the me two/3s to the left of the midtermal line. But I'm able to appreciate the posterior wall, some of the left atrium, and a little bit of the right atrium. All right. So, that's

23:08

Speaker A

again some views that I want you guys to appreciate because now what we're going to do is we're going to use those to really talk about some vessels that run along this surface. The first one is the right coronary artery. So, you have two

23:19

Speaker A

coronary arteries, the right and the left. The right coronary artery, we can appreciate right here. Left coronary artery, we can see poking behind the pulmonary trunk right here. Right? But let's kind of focus on the right coronary artery. So here we can see the

23:32

Speaker A

the aorta. It's going to give off this little branch and that's called your right coronary. Now a beautiful thing about the right coronary is we can see it moving kind of down down and then whoop it moves back. I can kind of

23:43

Speaker A

appreciate it here but instead of me doing that look you can see it's kind of wrapping around that right atrium. The reason why I say that is there's some branches that are given off along the way. The first one that is critical is

23:55

Speaker A

the essay nodal branch. Supplies the essay node. That's the pacemaker of the heart. Bro, definitely need to know that one. Another one is the right marginal artery. Some people call it the acute marginal artery, but I like to call it

24:07

Speaker A

the marginal artery, the right marginal. And it's going to come off here. And you'll appreciate that it can apply a decent amount of that lateral wall of the right ventricle. And so that's pretty critical to know, right? So if

24:19

Speaker A

there's kind of an occlusion here, you may kind of experience a lateral wall infarction.

24:25

Speaker A

All right, that's another branch. Another one that you can appreciate, we can kind of see it here, but we can better appreciate it from this kind of dorsal codal view here, which is your what your posterior descending artery. I

24:37

Speaker A

want you to remember there is two names for the posterior descending artery, the PDA. There's the posterior descending artery and the other one is called the posterior intervententricular artery because it runs in a little fat-filled groove called the posterior

24:50

Speaker A

interventricular sulcus. So just do remember there is two names for this vessel but I'll talk about this later.

24:58

Speaker A

Not all patients have blood flow. I'd say most of them probably 80% of their patients are probably have what's called right dominant PDAs meaning that their PDA comes off of the right coronary artery. Some people it comes off the

25:11

Speaker A

left and we'll talk about that is usually like the left circ. Um, it's not a lot of people and some people actually have their PDA fed by both the right side and the left side, but we'll get into that. All right. Again, the reason

25:24

Speaker A

why I mentioned all of these branches is that if you have an occlusion of the right coronary artery, pretty proximal, you can lose the lateral wall. You may lose some of the posterior wall of that right ventricle, and you may even lose

25:35

Speaker A

some flow to the to the SA node, and that's pretty bad, right? So, you can experience some pretty nasty complications. the left coronary. We can appreciate this one pretty nicely here.

25:44

Speaker A

It's really this is the main and it's gonna it's going to give off some branches along the way. And so let's kind of talk about those. So the first one again it's going to be that we we give it a lot of different names but the

25:57

Speaker A

left anterior descending artery. Um we call it theoretically you call it the widowmaker but the only reason we call it the widowmaker is if there's a clot in this because it supplies so much of your left ventricle your

26:09

Speaker A

interventricular septum that if you knock that out there's a strong chance of experiencing sudden cardiac arrest going into acute heart failure it's a pretty nasty one that you don't want to clot this up either way the l is one

26:23

Speaker A

term another one just to be aware of it's you're probably going to be like oh yeah well this was the posterior descending And they call that the posterior intervententricular artery.

26:32

Speaker A

Oh, I can call this the the anterior intervententricular artery. Why? Because there is a fat-filled groove called the anterior interventricular sulcus that it runs down. The other vessel is called the left circumlex. And this is that left circuit kind of sometimes you hear

26:47

Speaker A

the left circus a kind of like a little slang for maybe interventional cardiologists and stuff, but it's the left circumlex artery. It's going to kind of move around that left oracle and it can give off some branches as well.

26:58

Speaker A

Um, but what I want you to know is that it kind of loops around and you can kind of see it looping and then swooping right over here. And it'll give off some branches that supply more of that

27:08

Speaker A

lateral wall of the left ventricle as well. Um, and even a little bit of that posterior portion as you can appreciate here from that dorsal codle view. Um, so that's what I want you guys to be able to take into consideration. They do have

27:20

Speaker A

branches that come off, but these are probably the main ones that you'll kind of be tested on most often. All right.

27:25

Speaker A

Again, the profusion regions are critical when it comes to pathology because you can see here what the right coronary artery supplies. It's a pretty good chunk, dude. It can supply a very large portion of the right side of the

27:38

Speaker A

heart, some of the septum and even we can even appreciate in those patients who have a pretty dominant um right coronary supply, it can even give some supply to the posterior portion, right?

27:50

Speaker A

And again, that's just considering it as the whole thing. If you go off the branches, that right marginal, which is still kind of a branch off the right coronary, so if you block the right coronary, you're going to lose supply to

27:59

Speaker A

this one as well. That's going to supply more of that kind of lateral wall of the right ventricle. And again again applying that constant concept to the PDA it's still a branch off the right coronary. So if you olude that you're

28:13

Speaker A

again you're going to lose that posterior wall. So you can appreciate the right coronary supplies a very significant amount of the heart more of that right heart more of the posterior heart. And that's why you clot it off

28:23

Speaker A

you can experience a pretty nasty right ventricular myioardial inffection right heart failure. And these patients often don't do very good. All right, the LED again coming off of that left coronary.

28:35

Speaker A

The left coronary gives the LED which supplies a very good portion of the left ventricle, supplies a good amount of the free wall, supplies the septum, supplies the anterior portion of the left ventricle. So really, really critical structure here. And again coming off is

28:49

Speaker A

that left circuit is going to supply more of that high lateral wall, if you will, of the left ventricle. And it even gets into that posterior portion of the left ventricle as well, right?

28:59

Speaker A

especially on the left side. So that's some profusion regions that I think just points to the overall significance that if you clot these vessels, you can appreciate what would happen if you were to kind of imagine that you had what's

29:11

Speaker A

called an echo cardiogram. It kind of it tells you the contraction of the heart.

29:15

Speaker A

And that contraction of the heart may actually be you may have an area that's not contracting very well because it's not getting enough oxygen. It's infarcting. Um and so sometimes we can appreciate wall motion abnormalities.

29:27

Speaker A

Those can be made worse during drug in trials or like we can give them certain medications and that's a little bit beyond the scope of this or we can do stress tests to see if we can kind of

29:37

Speaker A

trigger that area to act abnormally on an EKG or act abnormally on an echo cardiogram. So that's why it's kind of really important to know the particular areas and then we'll apply this when we get into more of the medical aspect to

29:50

Speaker A

when we read EKGs. EKGs can theoretically point to a particular area that is infaring and the likely vessel to consider when you're snaking a catheter through these areas. But that's what makes interventional cardiologist so great is that they can find that out

30:06

Speaker A

when they're kind of going through the process. All right. So, last thing I want to kind of talk about is just giving another kind of really quick recap and appreciation to the dominant supply to the PDA. This is something

30:18

Speaker A

that if you're an avid desirable cardiologist, you really want to know the nitty-gritty that sometimes you may get hit with a question about this. It's kind of important to know. So the right coronary, I'd say probably 80 85% of the

30:30

Speaker A

time it's going to be the primary supply to the PDA. So it's going to supply that posterior ventricle for most of the scenarios. And so that's that's something I think that's probably the most often, right? So if you can kind of

30:40

Speaker A

imagine, I think a cross-section of the actual the ventricles and we can see here the right ventricle, here's the left ventricle. What we're going to appreciate is you're going to have some blood supply, right? And this is looking

30:50

Speaker A

at your kind of your interventricular arteries like the anterior descending which is either the left or the posterior. Uh and so what you can appreciate here is that the right coronary is going to give most of the supply to the right ventricle, right?

31:02

Speaker A

It's going to supply most of it. But in certain scenarios, that right coronary will then supply the PDA 85% of the time. So it'll give most of the supply to that posterior wall um of the right ventricle to the interventricular

31:15

Speaker A

septum. And as you can see, even a small piece of that posterior wall of the left ventricle. So that's 85% of the time, right? Small cases, we can appreciate that it's not coming off. Look, it just it disappeared. Now it's coming off of

31:29

Speaker A

the left circ. So in that scenario, we can appreciate that it's left dominant. This is now left anterior descending giving a branch like left circ. Left circus is supplying most of that lateral wall. But then it gives the PDA which

31:41

Speaker A

supplies the posterior wall all of that left ventricle septum and then on top of that even goes into that right posterior wall a little bit of the right ventricle. So you can appreciate that in about 8% of cases, right? And then small

31:54

Speaker A

cases like 7% of the time it may oh wow look it came off of both of them and that's kind of a co-ominance if you will in that scenario where you may have the right coronary and the left circ both

32:08

Speaker A

supplying that particular area. And so you can kind of appreciate that here with this purple which is the overlap.

32:13

Speaker A

All right. So those is just a little thing that if you want to know the nitty-gritty or if by chance you see this as a question or you're looking through the cadaavver you're like oh dude this is I'm following this and this

32:21

Speaker A

is coming off the left circ well that might be one of those left do oh wow it's coming from both that's the co-ominance most of the time you're probably going to see it falling off the the right coronary to feed the PDA all

32:31

Speaker A

right now we hit the arterial circulation which is supplying oxygenated rich blood to the myioardium what about whenever you perform gas exchange you need to get blood out of the myioardium and then take it back to the right heart where it opens up via

32:45

Speaker A

the coronary sinus into the right atrium so it can go back to the lungs get oxygen and then go back to the you know the left ventricle the aorta fill the coronaries again so we got to talk about

32:53

Speaker A

those so the veins here I actually like to do these in a way it's a little bit different where I like to think about the blood flowing along an artery um or this vessel this vein flowing along with

33:03

Speaker A

the big arteries so the first one is the coronary sinus you can see this is a big fat structure in the dorsal codal view it's the best way to see it and what I like about this view is that where's Is

33:13

Speaker A

it going to the right atrium where it's going to empty in? So now what I want to do is I want to think about it as tributaries, the things that are feeding into it. So let's go through that. The

33:22

Speaker A

first one is the great cardiac vein. Some people call this the anterior interventricular vein. Some people kind of make it actually separate from it. A lot of the times you can kind of consider them relatively synonymous and interchangeable. It's just where they

33:38

Speaker A

may differ is at a point where they're kind of moving. So, for example, if we really wanted to be particular, we could call this right here the anterior interventricular vein. And as it kind of gets ready to move up here, we could

33:50

Speaker A

call it the great cardiac. I think for simplicity sake, most of this is the great cardiac vein. And I like to do it that way because I know that it runs with which artery? The left anterior descending artery. So, that's what I

34:01

Speaker A

prefer to call the great cardiac vein. And this is going to take a lot of venus blood and move this wear to the coronary sinus. It's eventually going to take that blood from the mioardium, take it and empty it into the coronary sinus,

34:13

Speaker A

which empties it into the right atrium. All right, that's an easy way to remember this one. What's an easy way to remember the other ones? It's a kind of a similar concept here. The next thing is the small cardiac vein. The small

34:24

Speaker A

cardiac vein, you can appreciate that runs along which vessel right here? The right coronary. And so if it runs with the right coronary artery, it's going to be kind of bringing most of the blood from that right side of the heart. And

34:36

Speaker A

then what it's going to do is it's going to swoop around. So here I'm going to follow it and I'm going to come back over here. Here's my small cardiac.

34:43

Speaker A

Where is it going to empty? Right into the coronary sinus. All right. So we can appreciate that there. And again, it runs along the right coronary, swoops around back, right? And that's what I want you to think about. The middle

34:55

Speaker A

cardiac veins. You can't see it from the vententral view, but you can see it from that dorsal codal view. Here's the middle cardiac vein. I bet you can't guess what it runs with. Ah, you cheated. It's the posterior descending

35:06

Speaker A

artery. And so it's going to bring blood from that posterior portion of the heart. It's going to run its way up, kind of combine with the small cardiac vein, and empty into the coronary sinus.

35:15

Speaker A

These are the ones I really want you to remember because these are the ones that you're probably going to get tested on in some way, shape, or form. There's a lot of other small veins that you, if you wanted to go the extra mile, you

35:24

Speaker A

could know, but these are the big ones that I want you guys to think about.

35:27

Speaker A

There's also other ones that we can't even see, and there's these are called the the tabesian veins. They're small little veins. If you actually look at like a picture of a myioardium and you actually pull up the theian veins,

35:36

Speaker A

they're basically connecting within the myioardium. They're a small kind of like network. And what they do is they kind of just they don't actually run via this circuit, the small, the great, the middle into the coronary sinus. They

35:48

Speaker A

actually just empty blood from a myioardial circuit directly into the actual like cavity, the like the v left ventricular chamber, the right ventricular chamber, the lumen. Uh and so those are small structures. I don't want to go into that right here. But

36:01

Speaker A

just do remember there is some small little veins. And if they ever ask you, hey, what are the veins that don't actually directly um what are the veins that directly empty into the actual heart chambers? I want you to remember

36:11

Speaker A

theian veins. All right, cool. Let's now talk about the conduction system. The only way that the heart actually truly is able to contract is if we can send electrical signals from the top of the heart to the bottom of the heart. And it

36:24

Speaker A

has to work in a nice sequence. So we should know that sequence. The first thing is the essay node and that's why it gets in good blood supply and if it's not it's going to start actually having dysfunction and then it's not going to

36:33

Speaker A

be able to send those paces that we want. So really important structure sends a lot of electrical signals. It can send it to the left atrium via a bundle called the Bachman's bundle. So that's how it gets signals to the left

36:44

Speaker A

atrium. It also then travels through all of these like little interconnecting pathways into the AV node. The AV node is the electrical window, if you will, between the atria and the ventricle. How does it connect to the ventricle? It

36:58

Speaker A

connects to the ventricles by going and running through the septum and what's called the bundle of hiss. The bundle of hiss then sends the electrical signals down the interventricular septum where it then has to get ready to move into

37:12

Speaker A

the right ventricle and into the left ventricle. So then we have to split that bundle up into the right bundle branch and into the left bundle branch also called the toara branches. I like right and left. Then from here we need to get

37:25

Speaker A

this to then go and then deliver it to different parts of the mioardium and projections like the papillary muscles etc. So what do we need to deliver that final signal? That's your perkingi fibers. So this is the normal way that

37:38

Speaker A

the electrical signal should flow from the atria down into the ventricle so that we can have everything kind of working as a sensitium. We want it to all contract properly. Now we can appreciate with this electrical signal if it's being sent in a very proper way

37:52

Speaker A

and it's following a normal flow. The benefit of that is that the atria should then generate the signal to depolarize and then contract and that will give you a wave called the Pwave. Then what happens? The electrical signal will then

38:06

Speaker A

sit in the AV node for a very small short time and that's going to be this kind of PR interval, the time frame where it's kind of just sitting there and it's getting ready to go down into the ventricles. Then the electrical

38:18

Speaker A

signal will move down into the ventricles and it'll cause the ventricles to deolarize and that's called the QRS complex. And then what happens is usually during the QRS complex, the atria should be kind of like repolarizing but you can't see it.

38:32

Speaker A

It's hidden within the QRS complex, but we can see the ventricles repolarize and that's when it goes into what's called the T-wave. So, we can appreciate these electrical signals and sequences because they give us real time electrical activity of the heart that we can use to

38:50

Speaker A

interpret if there's any pathology. So, you can appreciate here that Pwave, the QRS complex, and T-wave. It's the electrical signal of the heart. That's such a great thing because we can identify if there is any pathology along the way. All right. And again, without

39:06

Speaker A

going too far in detail, if you see some abnormalities in the Pwave, you start thinking about something going on within the atria. If you think about some abnormalities in the QRS complex, you think about something going on with the

39:17

Speaker A

ventricles and them deolarizing. If you see the T-wave abnormalities, you start thinking about something going on with the ventricles repolarizing. That's what I want you to start thinking about.

39:26

Speaker A

Let's now move into the innervation of the heart. Let's talk about the nerves that are also going to supply the heart extrinsically. What does that mean?

39:34

Speaker A

Well, these nerves aren't necessary. If I cut these nerves that we're going to talk about that supplies the heart, it's not going to change the way the heart beats intrinsically. That intrinsic activity of the heart is dependent upon

39:45

Speaker A

what we just talked about. The SA node, the AV node, the bundle of hiss, the bundle branches of bkeni system. It's such a cool system that that structure can supply the heart on its own. It has the ability to intrinsically deolarize

39:57

Speaker A

the heart and then cause the heart to contract. But let's say that you were in certain scenarios where you needed to be able to change the way that the heart deolarizes faster or slower and you needed to increase the contractility of

40:11

Speaker A

the heart. That's critical. And so that's why we have intervation that is autonomic in origin, meaning that it can be parasympathetic and sympathetically controlled. So when I talk about this, let's let's kind of get into the two kind of divisions. You have what's

40:26

Speaker A

called the sympathetic division, and this is going to be via what's called that cardiac plexus. We need to know which area of the cord is controlling the heart, and that's usually going to be T1 to T5. So what happens is your

40:40

Speaker A

your sympathetic nervous system is really modulated by your medulla. There's something called the cardiac accelatory center. And that cardiac accelatory center, it's sending signals down. And it sends signals down to the spinal cord where it kind of synapses in

40:55

Speaker A

like the lateral gray horn via T1 to T5. And then those presinaptic neurons move out into the ganglia. And there's a bunch of different ganglia like the superior, the middle, and the inferior cervical ganglia that then send these

41:10

Speaker A

signals out via these sympathetic cardiac nerves. called the cardiac plexus if you will that then goes to particular areas of the heart. It can supply the SA node as you can see here.

41:20

Speaker A

It can supply the AV node as you see here and it can supply the ventricular mioardium the part of the myioardium that doesn't send signals. It's the parts that contract. That's all they do.

41:29

Speaker A

They don't depolarize intrinsically. And so if you think about that, if it can control the SA node, the AV node, and the myioardium that contracts, what do you think could happen? Well, sympathetic likes to speed everything up and just make everything more intense.

41:41

Speaker A

So, it's going to increase the heart rate and it's going to increase contractility. All of these things are designed to be able to increase your stroke volume, your cardiac output, your blood pressure. And that is why it's really critical to know that. All right.

41:55

Speaker A

The parasympathetic on the other hand, it wants to slow things down. It doesn't intrinsically control contractility, but we have in the medulla what's called the dorsal nucleus of Vegas. And and that's controlled by this cardiac inhibitory center. The cardiac inhibitory center

42:11

Speaker A

really really controls that dorsal motor nucleus of Vegas which then this nerve it can send really long pre gangleionic motor neurons out where it then synapses on these actual kind of cell bodies which these are going to be your post

42:26

Speaker A

gangleionic motor neurons. These are really really short and they primarily only terminate in the SA node the AV node. Can you appreciate how it doesn't really work on the myocardium? So because of that, what's the primary thing you would expect it to do?

42:40

Speaker A

Parasympathetics like chill, bro. I want to slow things down. So it's going to decrease heart rate. It really shouldn't affect contractility. And so I think that's a cool thing to remember because what we'll talk about in as you get into

42:52

Speaker A

medicine is drugs that can augment the activity or if there's disease processes that occur that increase the activity of the sympathetic and or or increase the activity of the parasympathetic or vice versa. So it's critical to know how

43:07

Speaker A

drugs or pathology can alter these pathways but also know that the heart isn't completely dependent upon the exttrinsic intervation to allow for it to modulate the activity of the heart.

43:20

Speaker A

All right. One other thing that I think is just kind of good knowledge to have an appreciation of is that visceral fibers so visceral aerence they basically pick up sensation from as you know visceral organs. So for example if

43:34

Speaker A

a patient had an MI and that MI causes necrosis of tissue visceral aerence that are kind of around this will pick up the signal and then it travels along the sympathetic pathway and so what happens is the reason why I say this is this may

43:46

Speaker A

cause something called referred pain so if a patient develops a mioardial inffection sometimes they can have referred pain it may refer to like their jaw their it may refer to their neck it may refer to their arm and I think

43:58

Speaker A

that's an important thing to remember and with that the myioardium is supplied by a lot of these structures that we talked about. But the paricardium has a nice good supply that comes from the frennic nerve. And that's why when

44:12

Speaker A

patients experience something like paricarditis, it's actually really important to remember this. It can cause that shoulder pain. So the frenic nerve is supposed to supply the diaphragm, right? That's its primary function. But its nerves do run through the

44:23

Speaker A

paricardium. So it gives off branches to the paricardium. And so sometimes that's important that if you develop paricarditis, it can irritate the frenic nerve which may cause some referred type of pain particularly to the shoulder or the trapezius area is what we kind of

44:36

Speaker A

like to say. All right. Now I want to kind of finish this up with appreciating how blood flows through the heart because I think it's a nice way of kind of ending off and appreciating how this amazing little

44:48

Speaker A

organ can do so much. So let's start by kind of recapping with the deoxxygenated circuit. Do you guys remember the three vessels? I know you do. the superior vennea, inferior vennea, coronary sinus.

44:58

Speaker A

Those are the three guys or or growls that empty into the right atrium. It's just they bring blood from different areas. Superior vennea is above the diaphragm. Inferior vennea below the diaphragm. Coronary sinus from the myioardium. They all empty into the

45:14

Speaker A

right atrium. Woo. Now, from the right atrium, where does it got to go? It's only going to move one way. And from here, we're going to move it down into the right ventricle through the tricospit valve. Once we're in the right

45:26

Speaker A

ventricle, we then are going to contract the right ventricle and we're going to send that blood up via the conus arteriosis up through what's this valve?

45:34

Speaker A

The pulmonary semile lunar valve up into the pulmonary trunk. From the pulmonary trunk, it's then going to divert into the right and left pulmonary arteries.

45:43

Speaker A

From there, it's going to go to the capillaries, undergo gas exchange at the alvoli, and come back to the left heart via the which structure? The pulmonary veins. The pulmonary veins are then going to empty the blood. How many?

45:57

Speaker A

Four. Two right, two left. Empty the blood into the left atrium. The left atrium is then going to have blood move down through what's the structure? The bicuspit or the mitro valve into the left ventricle. From the left ventricle,

46:11

Speaker A

the left ventricle will contract and push blood up through the aortic semi lunar valve into the aorta. And then from the aorta, there is two circuits.

46:22

Speaker A

One goes to blood all over the place to your head and all the way down to your little toe. But then the other one is it's got to go to the coronary circulation. So we're going to have the

46:31

Speaker A

systemic circulation which supplies blood if we'll go via these vessels. You see these here which is your brachiophalic, your left common, your left subclavian. This is going to supply most of the structures of the head, the neck, the upper extremities. And then

46:43

Speaker A

what's going to happen is we're going to move down via the descending. That's going to give blood to the thorax.

46:46

Speaker A

You're going to have structures in the abdomen with the abdominal aorta. It's then going to bifurcate, move down to the lower extremities. It's going to supply so many areas, but we can't forget about those little vessels that come right off of the base. And what are

46:58

Speaker A

those? You got it. The coronary arteries, and they're going to supply the myioardium. Do you see how we kind of brought this full circle? And the last thing that you can appreciate is that sometimes we're going to get chest X-rays a lot as

47:12

Speaker A

clinicians. And as we look at the heart, there's always something that you want to do as you go through a systematic read. That's for another video. I won't go through that. But I think that the nice appreciation of a chest X-ray is

47:24

Speaker A

you can see here a lot of the times what kind of identifies maybe potential abnormalities. So we can see here what's called the right heart border and we can see the left heart border. The reason why we mention that is that whenever you

47:38

Speaker A

have opacification or loss of distinction of those borders, it could mean something is going on in the lung.

47:43

Speaker A

Sometimes pneumonia masses etc. On top of that, if that right border is bulging out more, it might mean right atrial enlargement. If the left ventricle is bulging out here, it could be left ventricular hypertrophy. There's a lot of things, right? So, that's why it's

47:59

Speaker A

important to identify this and you may then need to do something else. The other thing is you can appreciate this little bump here called the pulmonary artery. Isn't that cute? And then with that, you can appreciate this aortic knuckle, which is kind of giving

48:11

Speaker A

you where the aortis is like a poor man's angagram, if you will, where the aortic arch is getting ready to kind of turn and getting ready to move down behind the heart. And I think that's kind of the big things to appreciate in

48:23

Speaker A

all of what the X-ray can kind of give you of the basic anatomy. And the reason why I say that is in patients who experience maybe enlargement of this pulmonary artery, they have pulmonary artery um you know potentially

48:34

Speaker A

hypertension that vessel can get big and it can cause enlargement there. You may see that um aortic dissections or aneurysms may cause enlargement of this portion which then widens out what appears to be the mediainum. And that's why it's really critical to know just

48:49

Speaker A

not only the anatomy of the heart when it comes to looking at it in a cadaavver, looking at it on images like an illustration, but also appreciating it on diagnostic images and how it can be utilized to help our patients. All

49:00

Speaker A

right, my friends, let's take a look at the right atrium. So, we look here, we got the opening of the superior vennea.

49:05

Speaker A

We got the good old opening of the inferior vennea. We're going to take a look at the anterior wall of the right atrium. We're going to appreciate the pectinate muscles. And then looking along the medial wall, you're going to

49:14

Speaker A

see that septum where the fossa ovalis is. If we kind of take a good look here, we see the opening or the osteium of the coronary sinus where it empties into the right atrium. And let's now move through

49:25

Speaker A

the actual tricuspid valve. You can see the cordate tendon here on the sides. You can see the good old papillary muscles. We see all this like rigid turbiculate carne. Oh, look at that good old pulmonary semi lunar valve. As we

49:36

Speaker A

rush our way in to what that pulmonary trunk, we get another view here and we can see a good look at the pulmonary semi lunar valve as we appreciate right here from multiple different views.

49:47

Speaker A

Now we can also see from the left side we have the pulmonary veins that empty in to the goal left atrium. We can see the septum there with that fosso valus as well. And then we're rushing our way

49:59

Speaker A

down through the tricuspid valve from the left atrium into the left ventricle. We see the cordate tendon. See all these big papillary muscles again all those rigid tubricular carne and there it is the aortic semi lunar valve that I'm

50:11

Speaker A

going to rush my way in to the base of the aorta at the base look what we see here we see the osteia of the coronary arteries the right and left ones so let's move into the coronary arteries we

50:22

Speaker A

can appreciate off of the right coronary artery there's a big branch called the marginal artery or the acute marginal artery as we move posteriorly we then move into this next branch here called the poster descending artery and you can

50:35

Speaker A

also see off the left side the left coronary you got the left circ again appreciating that left coronary we have two vessels here the anterior and interventricular artery and again we also have a diagonal branch of it getting a little bit more of a lateral

50:48

Speaker A

view you can see the circumlex artery that left circumlex and we can appreciate another branch called the left marginal optus this is good look at the actual veins that are around the heart we can see the coronary sinus that's the structure that

50:59

Speaker A

empties into the right atrium we have one vessel called the middle cardiac vein and that empties there and then also we have the anterior interventricular vein which eventually becomes the great cardiac vein and that empties into the coronary sinus.

51:13

Speaker A

All right. From here if we take a nice look here we can see a separation between the ventricles the interventricular septum and the atria the interatrial septum and then if we want to take another view we can actually appreciate how thick the

51:24

Speaker A

septum is and also the differences in thickness between the right ventricle and the left ventricle.

51:30

Speaker A

Man, I really hope that you guys like this video. Our team, MNA, who really works so hard on this, did such a great job animating it. If you guys can give her a shout out in the comments, she is

51:42

Speaker A

an amazing animator and she did all the work here. I just presented it. So, man, I really hope that you guys like this video. I hope that you learned a lot. I hope you kind of had fun along the way.

51:52

Speaker A

And man, I'm just so thankful. I love you guys. I thank you guys. And as always, my friends, until next time.

Topics: heart anatomy coronary circulation pericardium myocardium endocardium coronary arteries Anatomage table cardiac anatomy medical education Ninja Nerds

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