 Hi everyone this is Leah your lead course instructor for advanced eclinical training and I want to welcome you to our lecture series the Anatomy and Physiology Today we are going to be talking about the cardiovascular system and this is one of my favorite systems I worked for a long time in a CTI CU or a cardiothoracic intensive care unit So a lot of my patients had Open heart surgery they some of them had heart transplants. So This is a system. That's body system. That's very close to my heart Now the cardiovascular system consists of three main elements and those include of course the hearts You also have the blood vessels or the vasculature and also the blood There are four main functions of the cardiovascular system and that includes oxygen and carbon dioxide Transport a nutrient and waste product transport disease protection and healing and then thermal regulation or temperature control of the body the heart Has four is a four chambered Structure Consisting of mostly cardiac tissue now the right side of the heart moves the oxygenated blood To the lungs which is pulmonary circulation and then the left side of the heart moves the oxygenated blood Back to the rest of the body through the vasculature or the blood vessels, which is also known as systemic circulation Now there are four main layers of the heart and They include here the pericardium and you can see all of these here in this Picture to the right and The pericardium is a double wall Sack and it is the odd the outermost layer of the heart in it the pericardium is Used to protect and anchor the heart to the rest of the chest cavity you also have the epicardium and This is the visceral and the outermost layer of the heart and is actually part of the heart wall You also have them myocardium and this Layer consists of thick bundles of cardiac muscle that's kind of like bind it and twist it together And it's the part of the heart that is contracting and then you also have the endocardium And this is the innermost layer of the heart that is very thin And that lines the chambers of the heart So here you can see in this picture the chambers of the heart Again the heart has four chambers and they're divided longitudinally or Upping down by the heart septum The four chambers include the right atrium and the right atrium receives that this systemic blood from the body The right ventricle which pumps the blood into the lungs and then you have the left atrium Which receives the oxenegin of blood from the lungs and then the left ventricle Which then pumps the blood back to the system or the organ systems The heart also has four valves which you can see here. I've circled them So you can easily identify where they are The tricuspid valve is the valve between the right atrium and the right ventricle You have the bicuspid valve otherwise known as the mitral valve And this is between the left atrium and the left ventricle, which is right here You have the pulmonary valve and this is the valve that separates the left ventricle from the aorta Which we'll speak about we'll talk about the aorta here coming up very shortly And then you have the aortic valve and this is the valve that separates the left ventricle from the aorta Here we're talking about the great vessels now The great blood vessels provide a pathway or a roadway for the entire Cardiac circulation to run and these vessels include the superior and the inferior vena cava So you can see in this picture Superior is up here. The inferior vena cava is down here. So superior meaning above Inferior meaning below if you're familiar now with your anatomic body positions and And and this The heart receives the oxygen poor blood from the veins of the body through the large superior in a vena through the large superior and inferior vena cava and pumps it through the pulmonary trunk and then they pulmonary arteries So the pulmonary trunk splits into the right and left pulmonary arteries which carry blood to the lungs Where oxygen is then picked up and then carbon dioxide is unloaded and that pulmonary veins So oxygen rich blood drains from the lungs And is returned to the left side of the heart through four pulmonary veins and then the aorta Right here, which I said we would talk about Blood is then returned to the left side of the heart pumps out of the heart into the or aorta from which This is stomach arteries branched to supply essentially the rest of the the body tissues this picture here is of just this is stomach circulation, which we just talked about but it just kind of Visually describes it to you where How the blood moves from the vasculature through the heart So classes of blood vessels so first we have arteries arteries carry blood away from the heart Then you have the arterioles, and they are the smallest branches of the arteries You also have capillaries and capillaries are the smallest of the blood vessels And this is the location of exchange between blood and the interstitial fluid You also have venules and the venues collect blood then from the capillaries and then the venues run to the veins Which then return blood back to the heart the heart also has something called the conduction system of the heart and this is a network of Nodes or group of cells that can be either a nerve or muscle tissue and their specialized cells and Electrical signals that keep your heart beating So there are two types of cells that control your heart first You have the conducting cells which carry electrical signals, and then you have cardiac muscle cells which controls the heart's contraction So the conducting cells are what sparks the electrical signals and then the cardiac muscle cells control the actual Contraction of the heart because I'm sure we well note that the heart is a muscle So the cardiac conduction system sends the signal to start a heartbeat While also sending signals to tell different parts of the heart to relax and contract So this process of contracting and relaxing controls blood flow through your heart to the rest of your body So here is a pathway of the conduction cycle that we just talked about that you can see here in this picture The conduction system occurs Systemically through first the SA node and this is depolarization wave is initiated by the sine sine atrial node The atrial myocardium the wave then successfully passes through the atrial myocardium And it goes to the atrial ventricular node, and this is the depolarization wave Then spreads to the AV node and then the atria contract, and then you have the AV bundle and then Passes rapidly through the AV bundle and then to the bundle branches and Perkinje fibers So take some time to to go through each One two three four and five so you can just see how that cardiac conduction cycle works And we have something else called the cardiac cycle And so in a healthy heart the atria contracts Simultaneously then as they start to relax the contraction of the ventricles or the bottom of the heart begins And this is otherwise known as Cystele and Diastole so Cystele means heart contraction Diastole means heart relax heart relaxation So the cardiac cycle the term refers to The events of one complete heartbeat during which both atria invent that both the atria and the ventricles contract and then relax the length of an average heartbeat Approximately 70 times per minute 75 Times per minute so the length of the cardiac cycle is normally 0.8 seconds And the first heart sound that you hear is the love is caused by the closing of the AV valve For the atrial ventricular valves and then the second heart sound is the dub So you know the love dub so the second heart sound occurs when the semi lunar valves close at the end of Cystele And again, you can see here in this diagram how that whole cardiac cycle works So the last component of the cardiovascular system consists of blood So blood composition Composition is seen here. It's approximately 55% liquid and 45% cells Plasma is the liquid portion of the blood and it's a mixture of nutrients salts respiratory gases hormones and blood proteins and Then all blood cells could be divided into three categories. You have the urethra sites the leukocytes and the platelets Here we have the urethra sites or red blood cells and these are specialized and cells designed for oxygen transport Now they are shaped Biocon cave Which you can see here so biocon cave means They're kind of Flattened on the inside and this will help them travel through the capillaries easier and Mature red blood cells They don't have a nucleus or mitochondria or other membrane organelles And so they only have a lifespan of a hundred and twenty days and then they must be recycled Since they cannot divide because they have no nucleus And then you have the hemoglobin and this is an iron Containing protein that carries oxygen and carbon dioxide and then hematocrit is a measure of the proportion of blood that is Composed of red blood cells. So you you know probably heard by now, you know hemoglobin and hematocrit and this is you know, usually this is in What we can what we call that complete blood counts The hemoglobin and the hematocrit is used to is a blood value that's used to identify many different disease processes and is a measure of Really how healthy you are and we'll talk about that in another lesson and more in depth You also have lucosites and the lucosites are white blood cells White blood cells they help fight infection and defend the body through a Process called phatocytosis in which the lucosites or the white blood cells encapsulate and destroy foreign organisms White blood cells also help to produce transport and distribute antibodies as part of the immune response to a foreign substance or antigen and And there are five different types of white blood cells You first have the neutrophils and they have protect your body from infection by killing bacteria Fungi or fungus and foreign debris You also have lymphocytes and the lymphocytes consist of T cells Which are natural killer cells and B cells to protect against viral infections and produce proteins to help you fight infection Other ways known as antibodies You also have the eosinophils and these help to identify and destroy parasites cancer cells and assist basophils with an allergic reaction response And then we have the basophils and this produces an allergic Response like coughing sneezing or a runny nose and then you have monocytes which defend against infection by cleaning up damaged cells and Then last but not least we have thrombocytes Otherwise known as platelets and platelets are small colorless cell fragments in our blood that warm clots and stop or prevent bleeding Platelets are made in our bone marrow Which is a sponge like tissue inside of our bones, which we'll talk about more when we talk about the muscular skeletal system Thank you so much for joining me for this lecture series on cardiovascular If you have any questions or concerns or you need to clear anything up for you Please don't hesitate to reach out You know you can reach me by email or you can always schedule office hours with me as well with my calendar Calendar, so I hope you all have a wonderful rest of your day. Thank you so much