Circulatory System| How The Heart Functions as a Double pump

Circulatory System| How The Heart Functions as a Double pump



hey it's Michelle your CSC biology tutor in this video on the circulatory system I'm going to be paying special attention to hold the heart functions as a double pump so we know that in heart is a muscular organ and it's responsible for pumping blood and throughout the entire body so you need to understand that the heart is divided into the left side and the right side which is separated by a septum so it consists of four chambers we have the left atrium and the left ventricle and then the right atrium and the right ventricle so I mentioned that the heart functions as a double pump so that simply means that the blood is going to enter the heart twice so you will realize that I have the left and the right sides color-coded using red and blue so let's take a look at the diagram of the heart so as you can see the right-hand side highlighted in blue that simply represents the deoxygenated blood that will be passing through that side will be heart the left-hand side highlighted in red represents oxygenated blood that would pass through that side so you can clearly see the septum will separate these two sides of the heart to prevent the blood from mixing so you don't want the blood on the left side mincing with the blood on the right side so that septum is important in separating the different set two sides of the heart so let's pay attention to why the heart is really separated into two sides and why we have oxygenated blood coming through the left hand side and then deoxygenated both coming through the right hand side so you're going to show you the blood flow through the heart twice okay so like we're going to start on the left hand side of the heart but you need to understand that the blood is going to be entering each side simultaneously so as in heart is pumping the blood will be entering the left hand side carrying the oxygenated blood and then it's going to be entering the right hand side carrying deoxygenated blood is going to be all happening at the same time but for explanatory purposes I'm going to start with one side and explain what happens sooty blood as it enters the heart twice so let's start from the left hand side so blood rich in oxygen is going to be coming from the lungs so this is the oxygenated blood rich in oxygen coming from the lungs so you remember the lungs is responsible for taking in oxygen and breathing out carbon dioxide so that blood coming from the lungs is going to be rich in oxygen hence why it is called oxygenated blood so it's going to enter the left hand side of the heart through the pulmonary veins so that word pulmonary means related to the lungs so the pulmonary veins collects the oxygenated blood from the lungs and takes it to the left atrium so that's the first chamber the upper chamber usually smaller so that left atrium is going to receive the oxygenated blood and when the left atrium contracts remember the heart is made of muscular tissue cardiac muscle so in order for it to pump that cardiac muscle needs to contract so the left atrium is going to contract and force the oxygenated blood into the left ventricle now you're going to notice that we have a pair of valves here bicuspid valve also known as the mitral valve so that bicuspid valve along with all the other valves in the heart our B spot is responsible for preventing back flow we want the blood going in one direction only so you don't want that blood going back where it came from so as the left atrium contracts it squeezes and forces that blood past li bicuspid valve and into the left ventricle now the left ventricle once it receives the blood from the left atrium that in turn is going to contract and force the blood up past the aortic valve so we've seen another valve here so that a are tight valve separates the left ventricle from the aorta so that blood is going to be pumped up into the aorta passing the aortic valve and that oxygenated blood needs to be transported and circulated to all the organs of the body so the aorta is the largest artery in the body so it's going to be connected to various organs it's going to be responsible for transporting blood rich in oxygen to all the various organs so that's what you see these various branches as representing arteries are going to be connected to the different organs of the body so that blood ratio and oxygen once it has offloaded its oxygen and the various nutrients that it will be carrying to the tissues in the organs it then needs to return to the right hand side of the heart so by know that blood is going to be lacking oxygen so that's why we refer to it as deoxygenated blood so is laughing oxygen so it needs to return to the heart in order for it to collect the oxygen again and lungs so this deoxygenated blood is going to enter the vena cava and you realize you have two branches of the vena cava we have the superior vena cava which would be brain blood from the upper body and then the inferior vena cava which should be brain body brain blood from the lower body so these two branches of the vena cava is going to be brain in the deoxygenated blood into the right side of the heart so that deoxygenated blood enters the right atrium the upper chamber and then once our right atrium contracts it's going to force the blood past the tricuspid valve so you see in another valve here so that tricuspid valve remember the valves are responsible for preventing back flow so the blood passes the tricuspid valve and is forced into the right ventricle now the right ventricle when that contracts that is when a 4c blood passed the pulmonic valve also known as the pulmonary valve so that separates the likely right ventricle from the pulmonary artery so that deoxygenated blood is going to be carried through the pulmonary artery towards the lungs why is it going to the lungs typical oxygen because it's lacking oxygen at this point so when this deoxygenated blood enters the right hand side of the heart the sole purpose is to reach the lungs where it can collect oxygen again so know that we know that you should have an understanding of how the blood enters the heart twice let's just quickly review all that I've discussed already so the structure of the heart so remember it's divided into the left side and the right side and that is separated by a septum so the heart consists of the four chambers the left atrium and the left Trickle then the right atrium and right ventricle so in order to help you to remember which side has which type of blood you can use this acronym Lord lor D so left oxygenated right deoxygenated so that will definitely help you to better understand which side is carrying which type of blood and another note here so if you look back to the diagram you will notice that the left ventricle is actually thicker than the right ventricle the reason for this is that the blood that is forcing through the left atrium to the left ventricle on that that left side is responsible for carrying blood throughout the entire body so when the blood reaches the left ventricle it is going to be under very high pressure so that highly pressured blood is going to be forced through the aorta and taken to all the various parts of the body so the reason that the muscular walls of the left ventricle are much thicker than the right ventricle is because it has to withstand that greater force that greater pressure of the blood which has to be pumped up through the aorta and taken to all the various parts of the body with the right ventricle is thinner because it's not going that far the blood is not going that far it's just being taken to the lungs which is nearby so it doesn't have to withstand as high pressure as the left ventricle all right so let's let's review the blood vessels that are connected to the heart so on the left hand side you need to remember remember the left side bringing oxygenated blood taking out that oxygenated blood to the entire body so we have the pulmonary vein which would take oxygenated blood to the heart so that's taking the oxygenated blood towards the left atrium and the aorta is responsible for taking the oxygenated blood to all the organs of the body so remember that the aorta is the largest artery in the body so on the right side now we have the vena cava and we have two branches in superior and the inferior vena cava remember that the superior vena cava brings deoxygenated blood from the upper part of the body while the inferior vena cava brings the blood from the lower part of the body so the vena cava is the largest vein in the body so that is taking deoxygenated blood towards the heart now the pulmonary artery would be responsible for taking deoxygenated blood to the lungs to pick up the oxygen again so those are the important that vessels that you have to remember now in terms of the heart valves remember that valves will prevent backflow of blood so they keep the blood flowing in one direction so we have the atrioventricular valves which are between the atria and the ventricles so these including bicuspid valve or the mitral valve on the left side and the tricuspid valve on your right side now the other set of valves are known as the semilunar valves and these are found between the ventricles and the arteries so the aortic valve that would be phone between the left ventricle and the aorta well the pulmonary or the pulmonic valve will be found between the right ventricle and the pulmonary artery so now we've examined the structure of the heart and its associated blood vessels let's take a look at the two types of blood circulation so remember the heart acts as a double pump brain blood into the heart twice so basically this means there are two different journeys that blood will take before and after enters the heart so the first journey or Luca is a pulmonary circulation on this journey deoxygenated blood from the right side of the heart needs to be taken to the lungs to receive oxygen then once the blood has collected the oxygen from the lungs it enters the left side of the heart before it can go on its journey around the body so they said before a pulmonary means related to the lungs so pulmonary circulation describes the journey that the blood would take from the heart to the lungs to pick up oxygen and then from the lung city heart to deliver that oxygen now the second journey is a systemic circulation the blood that is rich in oxygen which enters the left side of the heart needs to be now circulated from the heart to all the body the body's tissues and organs so that is why the word systemic is used because it means that the entire body is affected so oxygen and the nutrients present in the blood can be delivered to the entire body so these are the two types of blood circulation pulmonary circulation and the systemic circulation so I hope you now have a better understanding of how the heart functions as a double pump bring blood into the heart twice

17 thoughts on “Circulatory System| How The Heart Functions as a Double pump

  1. Thank you so much. I never got this while in class it was too overbearing. Too detailed 😂😂 I hope I pass o

  2. You make biology so much easier. I am so glad that I found you, thank you very much this is very helpful

  3. you are heaven sent! a million and one thanks. I have biology exams in a few days, and for some reason, i was not grasping the whole heart topic. That L.O.R.D is wonderful and the topic has been explained so beautifully. Wonderful teacher you are! Now, if only you taught maths, I'm 100% sure i would pass it! Again, much love and blessings

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