Cardiovascular | Structures and Layers of the Heart

I ninja nerds in this video we're going to talk about the anatomy of the heart as well as the layers of the heart so first off a little bit about the anatomy of the heart what would you actually find it we find within the thoracic cavity but you'd find it within a special cavity in the thoracic cavity called the mediastinum so it's actually found in what's called the mediastinum there's actually different components and of the media style like the superior mediastinum the central anterior and posterior mediastinum we're not going to get into all that another thing about the heart is not only is it situated within the mediastinum but it's actually shifted about two-thirds to the left of the mid sternal line okay so it's kind of shifted the two-thirds to the left of the mid sternal line that's another important thing so when you look at the apex of the heart is actually pointing towards your left hip and the base is actually pointing towards your right shoulder nothing about the heart is that it's actually going to weigh approximately about 200 to 300 grams we generally say it's about the size of a fist okay so it's kind of just basic concepts about the heart and again apex is pointing towards the left hip and then the actual base is pointing towards the right shoulder now when we look at the heart we actually see a bunch of different chambers with inside of the heart for example if you look here you see these two top chambers here these two top chambers are called your atria right so plural form is the atria but for example since this is going to be on the right side of the heart this is on the left side of the heart this is referred to as the right atrium and this one over here is referred to as the left atrium the big difference between these is what is actually going to be filling them also so for example if you look at the right atrium a that's three big vessels that are inking blood into this cavity one is this bad boy right here this structure right here is actually called the inferior vena cava it's a big vein that's bringing blood from beneath the diaphragm from the lower appendages right as well some of the abdominal viscera and a lot of different other structures so this structure is called the IVC which is called the inferior michaela then you have the one that's above the diaphragm bringing blood from the head the neck and even the upper limbs so this is going to be called be superior vena cava so if the inferior vena cavas superior vena cave and we have another vessel that's emptying blood in here what is this structure your call this structure is actually emptying blood into the right atrium - and this is called the coronary sinus so it's the opening of the coronary science which is one of the structures that is basically taking blood from a part of a heart and returning it back to the right atrium you also have a little bit of scar tissue in this area you know whenever you're born generally there's a hole between the right atrium and the left atrium called the foramen ovale but whenever the actual fetus starts growing up and stuff like that the actual hole basically closes up and becomes a lot of scar tissue so imagine here I kind of draw like a little bit of scar tissue here and this scar tissue right here is representing what's called the fossa ovalis which used to be the foramen ovale in the fetus okay so they call this one here the fossa ovalis okay so that's that another kind of important thing about this is that there's some specialized nodal cells we talked about this in other videos so we're not going to spend a lot of time here but there's another like nodal cell a bunch of different types of nodal cells which are Auto remit autorhythmic cells they can generate action potentials and set your sinus rhythm it's called your s a node and we even talked about it more we had one right here which would be the AV node then we'll go into the bundle of hiss the right and left bundle branches and the Purkinje system we're not going to talk about all that right now okay we do that another video on the intrinsic cardiac conduction system all right so that covers that part now there's the next thing the left atrium what's emptying blood into the left atrium the left atrium is receiving blood from a couple different structures here it's all the same but they're basically bringing blood these structures here and over here it looks like it's emptying blood into this side of the heart but it's not coming around from behind the heart and it's dumping in over here so imagine it's dumping in over here from these two little red veins or there these guys are emptying blood into the heart and what's really important about this is that these veins are emptying blood that are coming from the lungs from the pulmonary circulation so because of that these are called pulmonary veins so these guys are here called your pulmonary veins and they're really important because they're bringing oxygenated blood from for example we said if it's the left side of the heart this is the left pulmonary veins bringing blood from the left lung whereas over here what you think these are called these are the right pulmonary veins and the right pulmonary veins are bringing blood from the right lungs but remember both the right and the left pulmonary veins are emptying blood into the left atrium okay now what's that what else was really important about this we covered that well now we got to talk about what is this partition here in between atria and the ventricles these are called valves and they basically are providing a one-way flow we don't want things to come back right so what happens is what is this valve right here called this valve right here is a special valve this is called the tricuspid valve so you can call it the tricuspid valve or another name for is you can call it the right atrial ventricular valve because it's separating the atria from the ventricles that's why I can call it atrioventricular valve and it's on the right side this one over here which is separating a left atrium from the left ventricle is called the bicuspid valve the bicuspid valve or another name is the mitral valve or the left atrial ventricular valve because of separating the atria and the ventricle on the left side now a little bit of thing about this valve here is if you look at it it's actually kind of cool because it's layered really really nicely when you look at the inner part of it it's actually consisting of different layers so it actually has a couple layers in here and it has a lot of collagen and elastic tissue on both sides and it also has a little bit of other different types of spongy tissue in here it's actually made up of two different layers called the zona spongy OSA the zone of fibrosis and even another one called the zona particular layers and there's no philia lining around it so just that you know the valve is actually made up of three different individual layers and again those layers of the zona fibrosis ona spongy OSA and those ona ventricular and then surrounding it is going to be a nice little epithelial tissue called the endothelial lining all right all right and that covers that part there now now that we have these valves separating these structures what's another important thing about these valves these valves are actually connected through these nice little collagen cords just actually make these collagen cords here there's these nice little collagen cords here let me get the tricuspid valve out of the way here there's these nice little collagen cords that are attaching to the cusps of the valves and they're there nice little collagen cords and they're anchoring the valves in a nice taut position tight position normally okay so these of a college I like courts are super super important what are these collagen cords are called these collagen cords are called chordae tendineae so what are these cords here called they're called chordae tendineae and the tendon a the chordae tendineae our collagen cords and what is their purpose they're basically collagen cords that are attaching to the valves and keeping the valve flaps really nice and tight to prevent them from back flowing up or actually ballooning back into the right atrium so this is important another thing is these chordae tendineae how do we anchor them down how do we keep them nice and tight there's the muscle that actually kind of protrudes out from this area here and attaches to these chordae tendineae so there's actually these nice little peg like muscles that are pumping out here and attaching to these chordae tendineae and these muscles are super super important because they're the ones that are anchoring these actual chordae tendineae down what you're anchoring these valves down what are these muscles here called these muscles are called your papillary muscles okay they're called your papillary muscles really really important the reason why is it when people get what's called M eyes or heart attacks basically what happens is ischemia occurs to these muscles and when they become ischemic and maybe even start actually being affected severely because of that they can become weak not able to contract if they can't contract the can't hold onto those chordae tendineae nice and tightly so what starts happening to the valve flaps they start becoming loose and whenever the right ventricle contracts it can push the valves back up okay and that can cause what's called a valve regurgitation and that's that's not good that's really bad okay and but it's more common over here on the bottom the actual less about where the bicuspid of the mitral valve is and just so that we're aware of this one this valve here I'm going to just abbreviate it is the tricuspid valve all right sweet deal that covers that now let's get into this part what is this chamber here called what is this chamber of the heart here call this chamber of the heart is actually referred to since it's on the right side and it's the pumping chamber this is called the right ventricle this is called the right ventricle very very important one okay now same thing over here on the left side you would still have those collagen chords let's say that I do the same thing here and I abbreviate my bicuspid valve here for just a brief moment here I put V V or mV because it can be bicuspid valve or it could be mitral valve or you can even call it left atrioventricular valve and just again what's that little recap here what are these little structures here called they're called your coordinate and na and the chordae tendineae our nice little collagen cords and they're anchoring the actual valves to these muscles here which are called the papillary muscles all right now the next thing is what is this chamber here called where the blood is actually coming down from the left atrium into this chamber right here this chamber here is called the left ventricle this is the left ventricle very very important pump this is a very very powerful pump now we get into the next thing the right ventricle will have to pump blood into this big old pulmonary circuit here so when it tries to pump blood into this pulmonary circuit it has to go through another set of valves what are these valves here called this valve right here is separating the right ventricle from the pulmonary trunk this is actually called your pulmonary trunk here so we called it and it actually looks like half of a moon so it's like semi loon right so they call it semi lunar but it's going from the right ventricle to the pulmonary trunk so it's called the pulmonary I'm going to abbreviate it semilunar valve okay this is called the pulmonary semilunar valve now there's another one that's actually separating the left ventricle from the aorta and it looks like half of a moon so what do you think that one's called it's called the aortic semilunar valve these are also very very important to okay so we have the pulmonary semilunar valve separating the right ventricle from the pulmonary trunk and Yorick semilunar valve separating life left ventricle from the order these are important what is the purpose of Valve's it's to prevent the backflow of blood to provide a one-way blood flow all righty and that covers that now what I need to do is I need to start going through the actual parts of the heart like actual a little bit more like thick structures wise so if you come right here you see how we're set what separates the left ventricle from the right ventricle what is that big old septum there called well separating the ventricles and it's in between them so it's called the interventricular septum so we call this bad boy right here if I were to kind of write it in between here they call this B inter ventricular septum so it's called the interventricular septum so the interventricular septum are separating the right ventricle and left ventricle it's really really important that we have that barrier because if not the blood could be moved back and forth mixing the blood this is actually a common congenital disorder which occurs in the tetralogy of Fallot where they actually can have what's called a ventricular septal defect terrible terrible situation there okay now you can't see it it's hard to see because we have the pulmonary trunk and the aorta blocking it but there's another septum in between the left atrium and the right atrium it's called the interatrial septum okay just so that we're aware of that all right so now what we started going all the layers i want to hit some of these great vessels that are coming off here real quickly so what is this guy ray Loewy said that there's the pulmonary semilunar valve separating the right ventricle from the pulmonary trunk so this whole big old beast right here is called the pulmonary trunk now the pulmonary trunk comes up and splits into two nice good old arteries that are going to go to the lungs so this one here is going to be going on to the left side of the whistling to the left lung so they call this the left pulmonary artery this one over here is going to the right lung so since this one's going to the right lung this would actually be considered to be the right pulmonary artery the next day the aortic semilunar valve is separating the actual left ventricle from the aorta so when the blood is going up here it's going through the ascending aorta so this right here is called the ascending aorta and then we go over into this nice little arch called the aortic arch now this is an important thing because if I were to label this right here the aortic arch there's actually three important vessels that come right off of the aortic arch and we're going to go with them in order so the first one is called the brachiocephalic so this first one right here is called the brachio cephalic that's the first one right here okay the next one is going to be called another special one and it's just called the left common carotid artery so we're going to denote that lçça left common carotid artery okay and the last one is going to be what's called the left subclavian artery okay and just so that you're aware if you really are curious because I know that you guys are the brachiocephalic is actually going to split into the lid onto the right common carotid artery so this is splits into the right common carotid artery and it also is going to split into another one called the right subclavian artery just so that you're wondering well where the heck is the right one for these two guys okay that's where it's coming from and then again what will happen is eventually the blood from the aorta will continue and go spread out to the multiple parts of the systemic circulation now let's cover the layers of the heart from inside all the way to out all right so we imagine here that Bloods going to be in these chambers but what's lining the different parts of the heart so if you see this kind of like inner layer that maroon mish layer right here this layer here is made with an endothelial tissue okay so it's made up of like an epithelial tissue with a little bit of aerial or connective tissue underneath it this one right here is lining the inner layers of the heart so we call it the endo car diem so we call this layer the innermost layer the endocardium okay then we go from the endocardium we go a little bit more out okay go a little bit more out here and we get into this middle muscular layer right there this middle muscular layer right here is made of a nice cardiac muscle tissue so a very very good cardiac muscle tissue and this cardiac muscle tissue that's the middle layer here this one is called the myocardium so it's called the myocardium and again what type of tissue is it made up of the tissue is made up of is going to be cardiac tissue so this is made up of cardiac tissue muscle cardiac muscle tissue all right very very important one now another little just kind of reference point here is when you're looking at the heart the left myocardium of the left ventricle as compared to the right myocardium of the right ventricle the left ventricular myocardium is much thicker because it has to pump blood for example the right ventricle only has to pump blood just to your lungs and back whereas the left ventricle s to pump blood all it under your little toe and then back up right so you can imagine why this one has to have a thicker myocardial because that should be a very powerful pump then we go into this outer blue layer this nice little teal layer here this teal layer right here is actually called as two names you can call it give it two names we can call it the epicardium or we can give it another name when I'll explain why we give it this other name is just a second another name that you can get it is called the visceral layer of the serous pericardium you guys are probably I think I'm going to stick with epicardium I wouldn't blame you just giving you guys options of what the other names are the next thing here is we have a lot of fluid here in this little cavity here there's a lot of what's called this pericardial fluid serous fluid here usually there's no blood or anything like that in this area here right under normal physiologic conditions you just be a nice like serous fluid this area right here is important because this is called the pericardial cavity this is called the pericardial cavity so it's just made up of a nice serous fluid now generally why is it's important because in certain situations when there's actually going to be less fluid there can be more friction between this blue layer in this green layer and that's really bad because I can cause what's called pericarditis which is a very very severe pain that these people develop because of the friction that's rubbing up against between these two layers it's like a stabbing pain that they say okay so it's again this is a really important that allows for these two layers to glide up against one another I'm doing contraction relaxation and prevent friction it's a very important function of that pericardial fluid last one here this green layer is actually going to be what's called this is where that's why that's other name is really important here they call this the parietal layer of the serious pericardium so this is the continuous layer so for example I want to show you right up here you see how we have this blue layer that's the epicardium or the visceral layer the serous pericardium look how it transitions you see there continuous with one another so it goes from here all the way to this one that's how it should be so normally you have a visceral layer covering the organ and a parietal layer covering the actual wall of that cavity okay in this case is the this pericardial cavity okay that's the parietal layer of the serous pericardium now on the outer parts of it we have this brown layer and this brown layer so important this Brown layer here is called the fibrous pericardium so it's called the fibrous pericardium super super important structure it's actually made up of what's called a dense fibrous irregular connective tissue so it's made up of dense irregular connective tissue super-important there's actually three functions of the pro fibrous pericardium three important functions here one of the functions is it basically helps to anchor the heart so it helps to anchor the heart to the surrounding structures that's one function to anchor the heart to the surrounding structures the other one is to protect the heart because it's a nice fit connective tissue it's going to provide a lot of protection to the heart for any type of trauma or any type of damage or any type of other types of things that could actually cause the actual inner parts of the heart to be affected so it's good at protecting our because it's a nice thick connective tissue and because of this fibrous pericardium the blood can't overfill with the actual blood the heart can't hold or fill with blood because whenever the heart is actually accumulating blood it can stretch well this fibrous pericardium is not distensible it doesn't want to stretch so it prevents the heart from over filling with blood and over stretching that's an important function so it prevents heart from over filling with blood right so that's another function so that is the function of the fibrous pericardium okay three very very important functions anchors heart to the surrounding structures protect the heart and prevents the heart from over filling with blood so that covers that one now in this we've actually talked about all the different layers and I just want you to understand one other thing that just because I did it for these ventricles it's the same for all the other chambers of the heart now another thing here is that if you look here for the mitral valve or the bicuspid aortic semilunar valve they're also covered with that nice endocardial lining okay so engineers we have pretty much covered everything that we're going to need to know here for basically the anatomy and the astrology of the cardiovascular system I really hope it made sense I really hope that you guys did like it if you guys did please hit the like button comment down in the comment section and please subscribe as always engineers until next time

Channel: Ninja Nerd

Views: 551,147

Keywords: structures and layers of the heart, anatomy of the heart, cardiovascular, structure of the heart, heart anatomy

Id: dgAbpwp9gF8

Length: 21min 55sec (1315 seconds)

Published: Fri Aug 04 2017