Parts of the Cardiac System (Heart Anatomy)

hi everybody dr mike here we're going to take a look at the parts of the heart so some of the anatomy associated with the heart [Music] now the first thing i want to look at is the layers of the heart so if we were to take a quick snapshot looking through the various layers of the heart there's three major layers you need to be aware of let's start from the inside and go out the most internal lay of the heart we term the endo which means inside cardium referring to heart this layer is lining the

hollow chambers of the heart and is actually continuous with all the valves of the heart which we'll talk about shortly the next layer which is the thickest layer of the heart is actually called the myocardium and myo as a prefix actually means muscle so this is that cardiac muscle this is what contracts in order for the heart to generate that force to pump the blood out and then the last layer the most external layer is what we call the pericardium and it's actually a pericardial sac which covers or encases the entire heart and there's actually

two layers of the pericardium the layer that's closest to the heart is called the visceral pericardium because visceral means organ and the layers further away is the serous pericardium okay all right what the pericardium does is it produces a fluid called a serous fluid and it simply lubricates the heart because as a muscle it contracts and moves and when it does this it generates force and friction and we want to minimize this friction because it can cause injury and that's what the pericardial sac does next thing i want to look at are the various chambers

of the heart so here is a more complex drawing of the heart but we can really simply just drop the type of heart you'd see in a cartoon for example right and what you can do is you can just break it up like this and now we've got four chambers two up the top now the two up the top are called atria that's plural and atrium is singular so just one and the two down the bottom are called ventricles and obviously you've got left atria left ventricle right here right ventricle we're always referring to the

patient so i'm standing like this so this is left this is right always remember that that's really important so obviously this is going to be left right left right okay that's the first thing 2h at the top two ventricles down the bottom next thing is that blood always enters atria always so you're going to have blood let's start here you're going to have blood entering the right atrium and blood will always flow from atria to ventricles now it needs to go through a space right it can't just move through a wall so there's a space

here and this space needs to have little flaps that open up and close open up and close and that's what we call a valve because valves are one way and there has to be one way we don't want this blood going up and regurgitating back now on the right hand side of the heart which we're looking at here right left this has three valves and it's called the tricuspid tri-meaning three cuspard referring to the fact it looks like little cusps right okay that blood then goes into the right ventricle and the right ventricle is going

to pump the blood out so blood always leaves ventricles now that's the right hand side let's have a look at the left hand side is going to enter the left atrium once it's in it's going to pass through some valves but on the left hand side there's only two valves and so we call it the bicuspid tricuspid on this side bicuspid on the other side it's also known as the mitral valve so we can write bicuspid and we can also do mitral then the blood flows into the left ventricle and the left ventricle is going

to eject that blood now you can also say i've drawn these in different colors because the right hand side of the heart deals with blood that has less oxygen and the left hand side of the heart deals with blood that has more oxygen and the way you can think about it is like this blood that's entering the heart that has little oxygen or less oxygen must be coming back from the tissues of the body right because it's just delivered that oxygen so this is coming from the body and what does it want it wants oxygen

so we need to deliver that blood to something so it goes back to the heart so it can generate more force and then the heart contracts and where's it going to get that oxygen from it's going to get it from the lungs now once that blood's gone to the lungs lungs and picked up that oxygen it needs to go back to the heart so this side is now dealing with blood that has more oxygen oxygenated blood and it's coming back from the lungs going into the left atria through the bicuspid valve into the left ventricle

and out and where's it going to go to the body deliver that oxygen and it's back again and so this is a nice simple way to begin your journey of blood flow through the heart and the various anatomical features we can translate that to a more complex picture of the heart and what you can see again is right atrium right ventricle left atrium left ventricle the blood comes back from the body not through one area but two what we call the vena cava and you're gonna have an inferior vena cava and a superior vena cava

and this is blood coming in back from the body and it goes back to the right atrium then it goes through that tricuspid valve which you can see here into the right ventricle it will contract and blood will be ejected out now we know it's going to the lungs right go into the lungs and we've got two lungs either side of the heart so obviously this blood vessel needs the split to go to the left and right lung but before it does that it needs to go through another valve and that valve we call a

semi lunar valve and it's what we call the pulmonary semilunar valve because pulmonary is referring to lungs then it goes up into this trunk so we call it the pulmonary trunk because it looks like a trunk in trunks branch and it branches to the right and left pulmonary arteries important point here arteries always leave right arteries always leave the heart and veins always return return to the heart so once it's gone to the lungs it's got that oxygen it then needs to go back to the left hand side so what we've got here are veins

because they're going back to the heart from the lungs so they're going to be called pulmonary veins and they're going back in and they go to the left atrium through the bicuspid valve into the left ventricle and then that left ventricle will contract and eject blood out of an artery which we have here called the aorta but again there's a semi lunar valve which is called the aortic semilunar valve that it must move through when it moves up through here this is called the aortic arch delivers it up to the head and neck and then

down to the rest of the body and again this is the aorta so this is a very quick run through of the important parts of the cardiac system