Structure of Human Heart

 

 The heart is a hollow muscular organ 

located in the thoracic cavity and in this article you will 

learn the basic anatomical terminology and the basic anatomical structures in the heart.

So here you can see the picture of heart.

main bottom chambers in the heart and 

these bottom chambers are called the ventricles so a left ventricle on one side and the right ventricle on the other side and the left ventricle particularly has a thick muscular wall of the left ventricle and of course the right ventricle also has a muscular wall but it's much thinner now why is it that the left ventricle has a thick muscular wall and the right ventricle has a thin muscular wall  as left ventricle that's pumping blood all around the body into the systemic circulation so the blood that's pumped from the left ventricle goes to your ears down to your toes up to your brain absolutely everywhere around the body all of the systemic circulation so it needs to generate a fairly high pumping pressure with a large muscular mass on the left side whereas as  the right ventricle is only pumping blood to the lungs if the heart is here then the lungs are only so there's not as far to pump the blood so the pressure doesn't have to be as high so the amount of muscular mass required is less now the key thing about the heart is it's in these four chambers now first of all we need to draw some arteries which are leaving the heart now this valve here guards the aorta which is the large vessel which leaves the left ventricle and the valve there points up the way and then between the ventricle at the bottom in the chamber on top there's another valve and that one points down the way like that so the left ventricle with one valve there and one valve there now the top chambers of the heart of a much thinner muscular wall so the muscle becomes thinner at that point and you can probably see here that we're starting to draw an additional chamber one of the top chambers the atria and draining into the atria there are four large veins in humans   two large veins draining blood into the top chamber the left atrium remember there are actually four in humans  now there's an additional chamber the left atrium so left ventricle left atrium pointing down the way valve pointing of the way and this valve between the atria and the ventricles below is called an atrial ventricular valve is between the atria and the ventricles so it's atria atria ventricular valve or atrial ventricular valve and this particular valve has two cusps it opens like this the left atrioventricular valve just got two cusps so sometimes it's called the bicuspid valve because it has two cusps but its proper name is the mitral valve so the left atrial ventricular valve is the mitral valve and it has two cusps the valve between the left ventricle and the aorta that is the aortic valve and sometimes these are referred to as the semilunar valves because they look a bit like half a moon so the aortic arterial valve or the aortic semilunar valve that's that one pointing up the way so this vessel is the aorta the large vessel leaving the left ventricle taking blood all around the systemic circulation and these bean veins here remember as there was four veins taking blood into the left atrium there the pulmonary veins of course pulmonary means to do with the lungs and the terminology is very simple an artery is any vessel carrying blood away from the heart while a vein is any vessel carrying blood towards the heart so because these are veins   they're carrying blood towards the heart because their pulmonary veins we can know that these are the veins that are carrying blood towards the heart from the lungs they're the pulmonary veins now we move on to the right side of the heart and in the same way here there's a valve pointing up the way like this and this connects to a large arterial vessel which quickly divides into two quickly divides into two one branch of this vessel go into each lung because this large vessel leaving the right atrium is the pulmonary artery  that pulmonary means to do with the lungs we know that an artery is any vessel carrying blood away from the heart therefore the pulmonary artery is the artery carrying blood from the heart to the lungs you would notice this valve is pointing up the way and this is the pulmonary valve that is the pulmonary arterial valve also sometimes called the pulmonary arterial semilunar valve so both of these valves are sometimes 

described as semilunar valves now a 

valve pointing down the way and the valve the left atrioventricular valve had two cusps this one has three cusps so I can't do this has only got two hands but that'd be one there one there and another one from underneath three cusps so it's called the tricuspid valve so the right atrial ventricular valve is called the tricuspid valve but just out of interest in passing  that the aortic semilunar valve and the pulmonary semilunar valve also have three cusps but it's this one that  is called the tricuspid valve now what we need to put on now is the final chamber of the heart which is the right atrium so  the right atrium and there are two large vessels flowing into the right atrium the vessel coming from above draining the top part of the body is superior the vessel draining the bottom part of the body here is inferior and both of these are referred to as the vena cava so the vena cava is the largest vein in the body the superior vena cava is draining the top half of the body and the inferior vena cava is draining the bottom half of the bobbling both.