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Ok, good evening everyone. Um, thank you all for coming to our, er, lecture series, our first lecture of the year. Um, just like can, before I do the introduction, can I just double check? You can all hear and see me? Ok, please, if someone could put that into the chart, somebody, please let me know. Yep. All good. Thank you very much, Hamza. Lovely. Um, ok, so, hello everyone. My name is Abd Rahman. Um, thank you very much to all of you who have confirmed that. That's good. My name is Abdur Rahman. I am the president of the Q UB Cardiology Society here at Belfast and today I've got with me Donovan Campbell and William Cartridge, James Cartridge. Sorry. Um, they are, they are, er, committee members of our society and they are um, treasurer and secretary. They'll be helping out with the lecture series and as you can see they're on the screen, we'll James today will be doing a lecture on cardiac anatomy. Um, and, er, I hope you guys all enjoy before, before we begin the lecture, I just want to emphasize that this is gonna be a kind of, er, er, week couple weeks long lecture series every, every Tuesday at, er, 6 p.m. and you can find us on meal and please follow us on all of our social media. Um, I hope I haven't missed anything. Donovan. If I have, please do, let me know, er, James, please do, let me know and I'll turn off my mic and camera and I'll let James take it away. So thank you all for joining. Yup. All right, I'll just get in. Uh OK. So can everyone see the screen and the laser pointer? First of all? Yeah. Ok. So, uh hi, I'm James. Uh I'm an cleaning student and today I'm gonna go through part one of the two part lecture series on cardiac anatomy. Um So, yeah, so basically today we're gonna try and cover kind of the extrinsic aspects of the heart. So, really concerning its position, our soy in the borders, uh pericardium heart wall, uh the coronary veins, great vessels and then kind of basically at the end uh innervation with the PMC QS. Um So yeah, let's get up. So kind of briefly and I want to look where actually is heart placed in the body. So really, it's in the middle mediastinum and this is kind of this area shown here and it is kind of to the left of the mid sagittal plane. And what it really does is it connects the pulmonary and the system, systemic circulations. And what I mean by axis here. Whenever you consider this, it's just kind of it's direction. So the base is kind of direct towards the right shoulder and it will the apex will be pointing towards the left hypochondrium. And the apex is kind of found in the left midclavicular line and a kind of an anteroinferior direction. So as you can see, there's the base in this aspect there, that's the apex. So this is the middle mediastinum and it's kind of below T four, which is the uh source of Ludwig. And in this inferior mediastinum, you have this metal mediastinum. So this next image will hopefully kinda let you appreciate that slightly better. So as you can see there's the base kind of at the right shoulder apex at the left hypochondrium. And you can see it's in this middle mediastinum between the lungs and and again, this is just showing this in a representation of kind of the rib cage on just to kind of emphasize it's kind of where it's placed and the direction it's facing. So there's a few different surfaces of the heart. And really, it's you've got your anterior surface, your posterior surface, your left and your right and then your inferior. So concerning this kind of anterior surface, and this is just a diagrammatic representation of the heart can be described as a kind of like a falling over her pyramid with the base, uh kind of its most posterior aspect and the apex of the most anterior part. So for this anterior one, we're looking at uh it's called the sternocostal and it's really up against the body of the sternum. And while your thymus atrophy, uh as you age it, the thymus, it can be placed in this aspect with the transverse thoracis directly in, filled it. And that's just a muscle on the posterior aspect of the sternum. It'd be found between the third and the sixth. Uh costal cartage is in. But also then we have our left and right surfaces. Um and these are called the pulmonary surfaces and they are kind of beside the lungs. So there should be a nice diagram here to kind of explain this. So, uh in this aspect here, obviously, the uh chest wall has been removed. So we can't really see any of the anterior surface and the thymus would normally kinda be located about there. But really what we can see is the heart is kind of sand between the left and the right uh lungs there, still the pulmonary surfaces. And this is just kinda allowing us to appreciate this anterior surface. Uh You can see it's kind of up against the body of the sternum. So the sternal costal and you have the transverse thoracis there and the 36 costal car costal cartilages. So now we're moving on to the posterior surface of the heart. Um This is really considered the base of the heart um behind it then uh you have your principal bronchi, uh the esophagus and then in kind of a posterior superior aspect, you have the great vessels coming off from the heart or arriving at the heart. And then in this inferior aspect, also known as diaphragmatic aspect of it, it's uh attached to the central tendon of the diaphragm. Then, and this should again be a nice diagram here. So as you can see posterior superior, you have these great vessels and behind you can see the toe going down, but the, the bronchi will be there alongside the esophagus and then the inferior service, you can see it's kind of sitting on the diaphragm with the central tendon of the diaphragm there. And again, this is just kind of allow you to appreciate kind of the posterior surface with the bronchi, the uh esophagus and kind of the great vessels. And then the inferior surface of the diaphragm. Again, you we've kinda considered the surfaces. Uh Now we're gonna have a brief look at the borders then. So there's kind of four main borders. So we'll start at the right border and the right border mainly considers really the right atrium here. And it's going kind of from the superior vena cava to the inferior vena cava, but a tiny bit of the right ventricle in there. Whenever we then consider the left part of the heart, it's mainly the left ventricle. So if you can see the laser pointer there, this is all left ventricle. So that's kind of the main aspect, the tiny bit of the left atrial appendage of the left auricle superior superiorly. Then with the border, you have the roots of the aorta and the pulmonary trunk. So you have your aorta there and your pulmonary trunk and then a portion of the uh right and left oracles, also the inferior border. Then as you can see here, all along here is mainly the right ventricle within the apex of the left ventricle. So that's the inferior border. So really, we're just kinda trying to appreciate where the heart is and kinda what's surrounding it first. So if you were to look at a patient then and say on today uh auscultation, which we'll cover next week, this is just really looking at on a patient where is the heart exactly situated. So again, we're just kinda considering four different areas. So superiorly, you have the inferior border of the second left costal cartilage. So that's there and it goes down to the superior border of the third, right costal cartilage uh in fairly, then we have the sixth, right costal cartilage. Um So kind of this aspect here to the fifth left intercostal space, midcollicular line, which is really kind of where the apex is located considering the right aspect of the heart. Um We're looking at kind of the third right costal cartilage down to the sixth, right costal cartilage. And then whenever we consider the left aspect of the heart, you have this fifth intercostal space in the mid line, going to perate to the inferior border of the second left costal cartilage. So now that we've considered that we're gonna have a look kind of at the heart surface then, so there's kind of a few Sulci and all sulci means uh sulcus is kind of the singular term for it, that just means it's a groove. So there's a few graves in the heart which arteries or veins will run through. And we'll consider the coronary sulcus first and it separates the atria from the ventricles. So the coronary sulcus kind of runs down along this side to the right and around this way to the left and goes around to the posterior aspect of the heart. And it's kind of forming coronary. So it's like a crown for the anterior interventricular sulcus. Then this is located on this anterior aspect, kind of along the border between the right ventricle and the left ventricle. So it's kind of located on the anterior surface and it's separating these ventricles. And as you can see, there's a few big blood vessels that run along there, which we'll kind of cover later on then considering the posterior interventricular sulcus. So as you've seen, this is just a continuation of the coronary sulcus around here. So as you can see, there's a coronary sinus with the right vessels there and the left vessels coming there. But now we're considering the posterior interventricular sulcus and this is located on the posterior surface of the heart. And again, it's separating the ventricles and you'll have uh an important artery running down the back here, which we'll talk about a bit later. So we've kind of considered where the heart is placed. Um kind of what its borders are, what the features are in the heart. So considering the grooves in the heart and OK, where you would place it uh if you were looking at a patient's chest, and now we're gonna cover the pericardium. So there's kind of two main types of pericardium. But first, we'll kind of consider this fibrous pericardium. And as you can see here, this is just showing the heart in the chest and the middle mediastinum. And it's just allowing us to appreciate um the different layers present. So that's the heart there. And we have our fibrous pericardium here and it's kind of this outer layer of pericardium. And this is this thick and fibrous connective tissue and it's really kind of uh attached to different areas so that the heart doesn't move about within the chest. So it's based, then you can see the diaphragm here and it's attached to the diaphragm by the pericardiophrenic ligament. So it's attached down here. This is the fibrous pericardium. So that's outer, tough outer layer, we then have the apex here um which is then kind of uh at the tunica adventitia of the great vessels. So at the apex, it kind of attaches to kind of the initial part of the great vessels and then will kind of reflect back on itself. And then along this anterior border here, you can see it's on the posterior aspect of the sternum and what you can't really appreciate because it isn't present in this diagram. And that uh it is attached to the sternum pretty much by these sterno pericardial ligaments. And this is just a diagram that's zooming in slightly. And we can see the different layers of the heart wall which will go through a bit later. And as you can see, we're talking to actually about this fibrous pericardium. So it's the outermost aspect of the heart. So now we're gonna have a look at the serous pericardium. So this is kind of this next stage in. And as you can see here, the serous pericardium is kind of the next layer in from the this fibrous pericardium. So as you can see, it's not this white layer on the outside, there's an initial red layer, then there's this kind of black potential space and then there's this red layer again. So whenever we consider the serous pericardium, there's really two layers and it's made up of mesothelial cells and this kinda helps it kind of secrete this pericardial fluid you have this outer pillar mm which you can kind of appreciate here and it's on the inner surface of this fibrous pericardium and then it will go up to the top. So as you can see, it kind of reflects at the rate of the great vessels and comes all the way back down again. And this is the inner vessel layer, this inner vessel layer will secrete this um pericardial fluid. Um And also it's also termed the epicardium. So it's the outermost aspect of kind of the heart wall. Mm Yeah. So then between the two layers of this serous pericardium. So this outer Paridol and this inner visceral, we have this pericardial cavity, which is this potential space and this is filled with uh ster pericardial fluid. And it can really range from 15 to 50 millimeters. And this fluid is secreted by pericardial cells. And what this does, it allows the heart to beat and it allows it lubricates the layers and it ensures that there isn't any friction occurring. So whenever we look at it slightly closer up, we have like at the fibrous pericardium uh la on the last slide. So what we're looking at here is this parietal pericardium, which is on the inner aspect of this fibrous pericardium, we then have the pericardial space. It this potential space filled with pericardial fluid. And we then have this inner visceral layer of the pericardium. And this is also termed the epicardium. So whenever we can send the pericardium, we can know the different layers. But it's important to understand that there's certain reflections that occur. So the pericardium will will kind of reflect and this is really for the layers of the serous pericardium. So you have this reflection, whereby you will have this uh uh or parietal layer than going around to form this inner visceral layer for the epicardium. And uh it's really a reflection and fusion of this tissue and superiorly, then it will kind of um reflect around the great vessels, these arteries. So we have these arteries in the form of the uh aorta and then this pulmonary trunk here and then posteriorly you have uh reflexions uh surrounding veins. As you can see here, these are the pulmonary veins returning to the heart. Ok. So there's two main sinuses to consider really. And the first one is this oblique pericardial sinus and it's really a posterior flexion kinda at the posterior aspect of the left atrium. Mhm And as you can see here in, in this kind of space there, this is this uh oblique pericardial sinus and it's just kind of a dead end up behind the posterior aspect of the heart. So that's that uh oblique pericardial sinus there. Next time we'll consider this transverse pericardial sinus located here and it is between the anterior and the posterior refractions. So as you can see, um it's these uh reflections here with the great vessels and then with the pulmonary veins. So it's kind of located there and it's superior to the left atrium. And this is quite important. So in cardiac surgery, surgeons will kind of use these as uh use this a transverse pericardial sinus as like a a way to identify the great vessels because it always kind of separate the arterial from the venous vessels here. OK. And this is maybe just a slightly easier diagram to look at. Um we can see our oblique pericardial sinus here up uh behind the left atrium and this is between the pulmonary veins. And then we can see our transverse pericardial sinus here and it is between kind of your great arterial vessels and your venous vessels. And this is for those anterior and posterior reflections. So that's your transverse periconal 10 there. So, the pericardium, we need to understand the layers of it, uh the different sinuses. Now, we're gonna have look briefly at uh as its own arterial supply. And the main uh arterial supply of the pericardium is this pericardiophrenic artery. And this is the branch of the internal uh thoracic artery then. So you can see here you have your pericardiophrenic vessels both on the left and the right. And you can see that coming and kind of infiltrating the pericardium. Um It should be noted also, however, which maybe can't the MS diagram, the coronary will supply part of the pericardium, but this is really on this visceral layer of the er pericardium. And this is because it's right on the heart wall or it's considered part of the heart wall uh regarding venous drainage, then you have the azar venous system um which will drain blood from the pericardium. And also these importantly, then uh the pericardium is innervated by the phrenic nerve. So you have C three, C four and C five. And you see the right phrenic nerve coursing down here and reaching the pericardium and then the left phrenic nerve here and reaching pericardium. And if there's any pain sensation or any kind of stretching, this will let you know. And this is sometimes why you can get this referred pain to the shoulder because you can get uh the pain signals going from here, getting a bit of confusion and then the pain will seem like it's elsewhere. So we've had like at the pre cardium. Now we're kind of moving in and we're like looking at what constitutes the heart wall. So there's kind of three main layers and if you look at it closely, technically before, so to start off, we have our epicardium and our epicardium as we should know is really just this visceral layer of the serous pericardium. So I follow along here with the laser, you can see that sir. And really, it's an arter layer, it's made of uh mesothelial cells. And these mesothelial cells will then produce this pericardial fluid that will go into the pericardial space and the nerves and the blood vessels. So the nerves um by nerves, I mean, the extrinsic nerves which influence the heart, which we'll talk about a bit later and the blood vessels supplying the heart. So, as you can see, her coronary vessels are kind of located here, they're present uh in this layer or kind of just close to next time is the myocardium. And as you can see, it's just a flare here. It's really the main constituent of the heart wall and it's made of these cardiomyocytes, um which allow for kind of the contraction of the heart next time whenever we move all the way in, we have our endocardium. And it's considered, well, it is the innermost layer. And so it will be uh interfacing with the blood inside of the heart and it lines the inner surface of the heart. And it's constituted mainly of these endothelial cells which line your blood vessels also. But you should really understand and it's quite important to kind of appreciate that there is a subendocardial connective tissue there and this is subendocardial. So that means that it's just below the endocardium. So it's kind of located about here. And this is important to understand because if this layer is damaged and that can affect the intrinsic conduction system of the heart, so that will be covered next week. But uh you have these uh fibers of the intrinsic conductive conduction system along here. Oh We've had a look at the heart wall, what supplies this myocardial or this myocardium. So what supplies the heart muscle So we're gonna have a look at the coronary arteries. Now, I've kind of broken it down into the left coronary, the right coronary. And then if you're looking at the heart from the anterior aspect and then the posterior aspect, so, uh we're gonna consider it the left coronary artery. Um it has a larger caliber than the right coronary. Uh and it comes uh from the left sinus of valsalva. So this is kind of an aortic rib, um kind of the aortic valve and it will branch off from there. It courses initially. So if we have a look here, the left coronary courses initially between the left atrial appendage and the pulmonary trunk. So you can see it coursing along there and typically, it will give off two main branches as you can see here, this green branch was for your left circumflex. And then this one for your left anterior descending and it supplies uh quite a large eye of the heart. So it'll supply your uh left atrium here, your left ventricle and then also your an interventricular septum. Next, then we're gonna have a look at the right coronary artery and here um it is smaller in comparison to the left corner and it will come off then from the right sinus valsalva. And as we can hopefully appreciate here, you can see the right coronary coming off and it's fine between the right atrial appendage and pulmonary trunk. You could say coursing down along this coronary CS that we kind of discussed earlier and it will supply the right atrium and it will also supply the right ventricle along with intraatrial septum kind of along here. Also, then the interventricular septum or part of it and then also the ATRIO ventricular node which will be within the heart and then the sino atrial node. So there'll be a branch coming off here to why. So as you can see the right comes along the posterior aspect, so that might be your sino atrial node. And then you have this posterior descending artery along here. So we've had a look at kind of the left coronary, right coronary where they kind of branch off from um what they go on to supply. But now we're gonna specifically look at the branches of these different arteries and we're gonna consider it an anterior and posterior aspect. So they both originate from the aortic sinus. So this is here and we're gonna consider the right coronary first. So it runs in this coronary sulcus here that we described earlier or this atrioventricular sulcus. And first of all, it will give us this uh sinoatrial nodal branch of the right coronary. And this is important because if that gets affected, that will affect your sinoatrial node and that will then affect the intrinsic conduction system of your heart. Um Next, then we can see, well, don't necessarily see in this diagram, but there is a Conal branch coming off. So we're considering this and this is considering the Conus arteriosus, which is here. So you'll get a blood vessel coming off the right coronate and uh supplying there, you will then have your anterior atrial branches. So this is supplying the right atrium and you will then have your anterior ventricular branches. So on the front of the heart, supplying the ventricle and then as you can see down along the bottom here, you have this right marginal branch that's kind of supplying the right border of the heart. This is just kind of a different, slightly more colorful diaphragm to see that. So you can see this Conus branch that I talked about earlier um by the atrial little branch kind of coming off, uh you then have it going down along and you have these right marginal uh branches and anterior uh ventricular branches. Also, that's it my phone, I'm sorry. So we've had a look at the right now, we're gonna have a look at the left. So um it's really running towards the anterior interventricular groove. And all that means is whenever the left cornea kind of comes out along here, you'll have this main bit going down, this interventricular sulcus, the anterior interventricular sulcus, and it bifurcates into two terminal branches. So you've got your left circumflex and your led. And whenever we consider the anterior interventricular artery, which is also known as the left, anterior descending artery, again, you will have a Conal branch which doesn't really represent it here, but it kind of comes off there and supplies this area. You then have your anterior ventricular branches. So these bits coming off there and you will then have a diagonal branch. This is kind of a main vessel coming off there and supplying that part, not run down towards the apex. Then we have the circumflex already. So it will kind of come off and go around the coronary sulcus. And as you can see, it's more kind of on the posterior aspect to see this left marginal branch of the circumflex, your left marginal, right, sorry. This is just the diagram we've seen previously, but we're just gonna look at the left side. So you can see the left cornea coming off. You got your circumflex L ad you got your Conus branch, then you got anteroventris uh arteries with then your um diagonal and then uh starting back is going around to give your marginal. So we can send the anterior aspect. Now we're gonna look at the posterior aspect. So whenever we're looking at the posterior descending artery, you can see it uh along here if you follow this pointer, um it's uh in the inferior or the posterior interventricular groove and it's a terminal branch or most commonly, it's a terminal branch of the right coronary artery. So you can see the right coronary artery coming around and then kind of traveling alone and form this PDA, posterior descending artery, considering then the circumflex, it maybe slightly covered by the great cardiac vein there. But uh the left circumflex is coming around and will then give an inferior left and particular branch. Um So kind of that's one along here there. And whenever you consider dominance in a heart, if someone says uh someone is left heart dominant or right heart dominant, all this really means uh is that it's really considering the posterior and different particular artery or the posterior descending artery. And it's really just considering what main coronary will uh kind of dely that or what uh as a branch of that. So in 80 to 85% of cases, the right coronary will supply the posterior descending. And in 10 to 15% of cases, the left will supply this posterior descending. Uh Now we're gonna have a look at the cardiac veins. So there's kind of two venous systems to really consider here. So you have your greater cardiac venous system and you have your smaller cardiac venous system. But I most people will mainly kind of fixate on the greater cardiac venous system. And it's really considering the coronary sinus and all of its main Trib tributaries along with its anterior cardiac veins. So along the uh anterior aspect, your atrial veins and then you've been checked your septum veins. So that's kind of in the, in the aspect of the heart. Then whenever we look at the smaller cardiac venous system. They're kind of termed the smallest cardiac veins or the SBE veins. And these are quite small, as you can see with 0.5 to two millimeters in size and they will drain directly into the heart chamber. So this can occur on both the left and right side of the heart. But really, it's more likely to occur and drain into the right side of the heart do like we did to the arteries. We're gonna have a look at the anterior aspect and then the posterior aspect. So we're having like a disc great cardiac vein first and that originates from the apex of the heart and it will run alongside the L ad. So the le this left anterior descending or this anterior interventricular artery and it will then as you see course around here in the coronary sulcus and fold the circumflex artery and it will receive venules from the ventricles and the left atrium and the left marginal vein also, then you have these anterior veins of the right uh ventricle. So they'll kind of be located here and here and also your right marginal vein which is located here and that'll kind of feed into this um small cardiac vein then that's draining from the right ventricle. Now, we're gonna consider the posterior aspect and this is kind of where it's all happening for the cardiac veins. And whenever we look at the posterior aspect, what we really consider or concerned about is the coronary sinus located here in this uh atrioventricular or coronary sulcus. It's considered the largest vein of the heart and it's in the coronary sulcus kind of on the inferior aspect. And this will drain uh blood for the majority of the coronary vasculature uh into then the right atrium. Here, it has many tributaries. So if you have a look at them, now you have your great cardiac vein, which is located in anterior aspect, you then have your middle cardiac vein and your middle cardiac vein will run alongside um your uh posterior descending artery, which is kind of in the uh inferior or the posterior endoventricular grave. You have your small cardiac vein which runs with your right coronary uh and the uh the coronal sulcus and then you have the inferior vein of the left ventricle, which was normally kind of what we considered the posterior cardiac vein here. And then you have the big vein somewhere as well. That's the main one. So we've covered the coronary vessels and we've then covered the veins. Now, we're gonna move on to consider the uh aorta or sorry, the great vessels of the heart. And as you can see here, these are coming off up here um towards the back as well. So we'll kinda go straight on. So, first of all, uh the aorta, um it is uh bringing oxygen rich blood from the heart out then to the systemic circulation. Definitely going from the left ventricle through the aortic valve, right, the ascending aorta um from which the coronary will branch off as you can see there. And then we'll go into the arch of the aorta at the arch of the aorta. You have this brachiocephalic trunk as you can see there. And then the brachial phallic trunk will then split into the right uh the C and then the right common carotid. And as we progress around, then we have this left common carotid on this left subclavian. So we've had a look at the ascending and then, then the arch of the aorta. Next, we're going to consider the pulmonary arteries. And this is deoxygenated blood going from the right ventricle into the pulmonary circulation. Uh It begins as this kind of common pulmonary trunk. So it goes from the Conus arteriosis into this common pulmonary trunk through the pulmonary valve. And then at the level of about T five or T six, this common trunk will then bifurcate, going then into the left and right lungs. And this is to bring the oxygen blood to the lungs to then oxygen. This is just looking at kind of the posterior aspect here. So we can see um the ascending aorta going into the arch of the aorta, then going down into the thoracic aorta. But we're not considering that just now, but really, this is just to allow you to appreciate the bifurcation of the pulmonaris at T five and T six, we've got this common trunk and from this common trunk, you've got your left pulmonary artery and then your right pulmonary artery. So next, then we're going to have a look at these pulmonary veins and these pulmonary veins will bring oxygen rich blood from the pulmonary circulation. So the the oxygenated blood coming to the rights of the heart will go to the lungs at the lungs, it will get oxygenated and then we'll return to the left atrium and we can see these uh pulmonary veins. So there's one there that is the right superior, the right inferior, the left super and then the left inferior and we'll be able to see that slightly better uh in this diagram. So, um this is kind of the base of the heart. Um This is the left atrium um here and fitting into the left atrium, you have your left palmary veins and then you have your right palmary veins. So you've got a superior and inferior for each lung. Um I'll just go back a bit there. So next, we're gonna look at the superior Vena cava and this is bringing deoxygenated blood from the upper body. So from up here to the right atrium located here. So as you can see, you have this union of the brachial phal veins coming from the jugular and Suan and then going into this uh superior vena cava and it will drain into the superior aspect of the right atrium at the level of the third rib, then whenever we look at the inferior vena cava, um it's bringing deoxygenated blood from the lower aspect of the body. And really, it's formed by this union of the common ileac vessels in the pelvis and it enters the pericardium. So the pericardium is just move back around the heart at about to and will gain into the inferior aspect of the right atrium. So hopefully, you can look at this slightly better. So you can see the union of the brachycephalic veins forming the S VC, which is going to the superior aspect of the right atrium and then the IVC going up and going into the inferior aspect of the right atrium. So next time we're going to have a look at the extrinsic innervation of the heart. Um There is the extrinsic innervation of the heart and this is kind of the nerves outside of the heart having an effect upon it. And then we have the intrinsic uh innervation or intrinsic uh conduction system of the heart, sorry. And this can impact it. So whenever we consider the extrinsic regulatory system, it's kind of a series of autonomic nerve fibers which will influence the heart and it originates from a network of nerves. And this network of nerves is termed the cardiac plexus. And the cardiac plexus is really formed of uh sympathetic nerve fibers, our sympathetic nerve fibers. And then these visceral afferents which the life kind of to inform the body kind of what's going on there. And we're considering the anatomy of it them. So um it'll be along the anterior surface of the trachea and then along the posterior surface of the standing aorta and the pulmonary chunks are down here. So you can see this uh cardiac sympathetic chunk going down a parasympathetic, which we're gonna find out is the vagus aspect. And then you have this kind of superficial cardiac plexus here and then this is just with that part removed. So we're just looking at the trachea. And as you can see on the anterior surface of the trachea, you have this formation of a deep cardiac plexus with the sympathetic nerves, paras, parasympathetic fibers and these visceral afferents. So we're just gonna talk briefly about sympathetic trunk. Is this a source of sympathetic innervation? So you have these, you have this innervation coming from the cervical uh sympathetic trunk and then thoracic and it will come down and then feed into the heart. And then we have this parasympathetic innervation from the vagus nerve, which is the 10th cranial nerve and the sympathetic system. And the parasympathetic system will really uh influence chronotropy, chronotropy if considered chronograph, that's to do with time to and influence the uh the quick the heart will beat. So it's heart rate anopia them um is considering the force of contraction of the heart. So, if your sympathetic uh system kinda kicks in, you're gonna get uh increased heart rate and more forceful contraction. And if you influence heart rate and the uh strength of contraction or the influence of the strength of contraction that will then influence your cardiac output. So this in a innervation of the heart will be able to affect your cardiac output. So, uh we have the sympathetic innervation from the sympathetic trunk going down. And this is for the superficial plexus, our sympathetic innervation as I pointed out before you've got your left vagus nerve and then your right vagus nerve. This is forming this superficial plexus here. This is just the same diagram from before. So what we have here is our uh our vagus nerve coming down, both left and right along with the sympathetic trunk. And this is just following this deep cardiac plexus to then kind of innervate the heart. Oh This is kind of a quite a quick run through of the uh kind of the intrinsic aspect of the heart or sorry, the extrinsic aspect. So we've had a look at where the heart was placed. We've had a look at the coronary vasculature, the pericardium and the heart wall. So kinda covered the extrinsic aspect. Next week, we're then going to cover the uh intrinsic aspect. So it will be like uh the right atrium, the right ventricle uh on both sides, the fibro skeletons, heart heart valves, and then the intrinsic conduction system. So that'll be coming up next week. Um There's a few questions still to come here. So I've got five Mc Qs just to check your understanding. But um if you find this useful or think you might get benefit, there's gonna be quite a comprehensive teaching series and this is kind of kicking it off of kind of over 20 sessions. So I think it'd be quite good to uh follow the Instagram account. Um It would be where we kind of post uh what we'll be getting up to. Um So I can put this up at the end if anyone wants to see it again. Um But now that I've kinda taken you through everything, I just wanna check that. Um You have kind of understood and see uh if you'd be able to answer a few questions on it. So what's gonna happen here is I will show you uh an M CK and then a pole will be put up in the chart and then if you can just answer the pool, um we'll give you a bit of time to complete it and then we'll just go through for these five questions just to finish it off. So have you get another minute? OK. Getting a few more responses. So, in what layer of the heart are the fibers of the intrinsic cardiac conduction system found endocardium, subendocardium, the myocardium, the subepicardium or just the epicardium. OK. So we've got over 20 responses there. So I think we'll crack on with this. So whenever we consider the intrinsic cardiac conduction system, while I haven't covered it fully. This week, I did mention what layer of the heart wall you might expect to find this and it, it's the subendocardium. So it's the layer below the endocardium. And it will have these uh electrical fibers which allows for a conduction of the um action potential from the cyto arial node to the atrioventricular node down then to the bundle of hiss and then through the fibers. So this is the subendocardium. So that's kind of leading on to what we'll cover next week. Do uh M CQ two, I'll read it out first and then I'll put up the pool. So, uh which pericardial sinus is used by cardiac surgeons to identify the main arterial great vessels during surgery. Is it the sagittal sinus, longitudinal sinus, oblique sinus, transverse sinus or the coronary sinus? Well, it may not have been on the slide. Um A dead man. That's an easy one to remember. Good. I'll wait for a few more responses. This is an important one for surgeons just because it lies the distinction between the um ascending aorta, the pulmonary trunk and then your um S VC, it allows you to separate the arterial vessels from the venous vessels. And if you wanted to say that was bypass, that's important to know. So, yep. So it is the, the transverse sinus. So the transverse sinus is one of these reflections um of the pericardium. So this kind of changing from the um outer pra to the in intervial. And it's kind of at the superior aspect of the left atrium and it separates these arterial and venous vessels. Ok. Very good. So doing well, so far. So the next one then is uh concerning the coronary arteries. So the posterior descending artery most commonly arises from which vessel is it a the coral branch? B the sinoatrial nodal branch, the the left anterior descending artery, d the right coronary artery or e the left circumflex artery. And the key word to this question is, well, key two words, sorry is most commonly. So this is really asking you in the most common form of dominance of a heart, which vessel um is the posterior descending artery or the inferior uh interventricular artery as it can be termed. Um what uh is what derives that vessel or what is that vessel derived from? Sorry, give a little bit more time. Sure. Um ok. Uh Call it there. So, yeah, uh very good. So it's the right coronary artery and, and a well, the most common form of dominance for the coronary vasculature of the heart is uh a right dominant heart. And this is the case in 80 to 85% of patients. And in that case, that means that the posterior descending artery also termed the posterior uh interventricular artery or the inferior interventricular artery. And it will normally arise from this right coronary artery. Whereas it was the left dominant heart, the posterior descending artery will come from the left coronary. Really? The left circumflex? Ok. Two more questions. So, uh what is the largest cardiac vein? Is it the metal cardio f the coronary sinus small cardiac vein, the great cardiac vem or the thebesian vein and I will pick the pull up now. Great for a few more responses. Ok. So what is the largest cardiac vein? Um Yeah, not a tech question, but it's the coronary sinus. So coronary sinus, what it is a sinus is still tactic to the vein and all of the kind of main tributaries of the coronary veins. Well, the cardiac vein sorry will feed into this coronary sinus which look in the posterior aspect of the heart and the kind of the coronary sulcus and it will then feed the blood back into the right atrium. Last question. So at what vertebral level, does the pulmonary trunk bifurcate into the left and right pulmonary arteries? Is it C five to T six T three to T four, T five to T six T five to C six and or T six to T seven. So at what approximate level or what approximate vertebral level, does the pulmonary trunk bifurcate into the left and right pulmonary arteries is the last question. OK. So um the answer is T five to T six. So that approximate level you will have this pulmonary trunk coming from the right ventricle in the Conus arteriosis up and then bifurcating into your left and right um pulmonary arteries and then go in the lungs to get uh hopefully oxygenated um deoxy blood. So, yeah, so just to reemphasize them, uh next week's lecture um on the 29th. So next Tuesday at six o'clock on me, um there will be part two of this cardiac anatomy, uh kinda se many series. Um So I consider the itching and the ventricles, the fibro skeleton of the heart and then the heart valves, your atriventer valves, semilunar, and then kind of the intrinsic conduction system. So we've done the extrinsic this week. Hopefully they can cover um intrinsic next week and uh without uh the anatomy talks, then they'll be leading into physiology uh lectures and uh yeah, I hope you uh got something out of us. Um I hopefully enjoyed it. Um This is the QR code, then if you want to sign up to the Instagram, if you haven't already or follow us on Instagram, and it will um essentially show what events are on. So we're hoping to do a lot more of the teaching series kind of throughout the whole year and to cover uh student sitting sessions and hopefully experts in the form of doctors and surgeons. Um Yeah. So thank you for attending. I'd appreciate if you take the time to fill out the feed park form, this will allow you to uh get a certificate of attendance and then also you will be able to get access to the slides, um kind of maybe tomorrow at some stage um for your own viewing. But yeah, thank you very much straight up. I appreciate it. Thank you very much for that lecture James. Um That was very comprehensive. Very good. So I've sent the feedback to everyone in the chart. Hopefully you can all take a second to fill that out. And uh as James said, you'll have access to the slides sometime tomorrow and a certificate as well. Hopefully as soon as you fill out the uh the feedback. So, yeah, thanks very much. Everyone. Have a good evening and we'll see you next week. Uh Same location, me and same time. Thanks guys. If you have any questions.