Cardiovascular System Function – Circulatory System – Biology – NEET 2021 – GCSE – IGCSE – Edexcel. If you like this video please subscribe to support our work.
Knowing the functions of the cardiovascular system and the parts of the body that are part of it is critical in understanding the physiology of the human body. With its complex pathways of veins, arteries, and capillaries, the cardiovascular system keeps life pumping through you. The heart, blood vessels, and blood help to transport vital nutrients throughout the body as well as remove metabolic waste. They also help to protect the body and regulate body temperature.
The cardiovascular system consists of the heart, blood vessels, and blood. This system has three main functions:
Transport of nutrients, oxygen, and hormones to cells throughout the body and removal of metabolic wastes (carbon dioxide, nitrogenous wastes).
Protection of the body by white blood cells, antibodies, and complement proteins that circulate in the blood and defend the body against foreign microbes and toxins. Clotting mechanisms are also present that protect the body from blood loss after injuries.
Regulation of body temperature, fluid pH, and water content of cells.
Okay we have already discussed that why we need a special transport system like cardiovascular system and mammals right very briefly we talk about what are the functions of this cardiovascular system very very briefly we will discuss in detail later right because this lecture is just basics of cardiovascular system so what could be the function of this cardiovascular system you can see it it is taking the oxygen from here it is taking the nutrients from here and providing it to the peripheral cells so we can say that one function is that cardiovascular system or this transport system is responsible for transport of nutrients transport of nutrients like glucose or amino acids or fatty acids right and of course like oxygen to the tissues secondly not only it is transporting the needing needed needed substances to the peripheral cells it is also removing the waste product for example it is taking carbon dioxide and taking it to the lungs back to get it back to the environment or it is taking some other metabolic waste and taking it to the kidney and getting it eliminated through the urine right so we can say the second function is that transport of yes of metabolic waste wallet waste but what we will say transport of nutrients and oxygen from gastrointestinal system and from lungs to the tissues and transporting the metabolic waste from the tissues to the elimination surfaces right those surfaces those exchange services which eliminate the waste products out of the body like kidneys or like carbon dioxide transported to the lungs to get it out right then it has one more function yes you know uh blood has very special type of cells we call them white blood cells what we call them white blood cells these white blood cells there are many types of them we’ll discuss it later white blood cells fight with the infection for example if some bacteria enter here there is some damage in the skin and some bacteria have come here then blood will bring white blood cells here and white blood cells will go out and deal with these microorganisms in the same way so what we can say that it is responsible to transport the immune cells immune system cells so what it is doing not only it is providing the cells where needed nutrients and oxygen not only it is removing the metabolic waste but it is also doing one very important thing that transporting transport of immune cells immune cells like white blood cells to those area where they are required right any other function can you tell me yes yes another thing some some substances are secreted by some cells for example in the pancreas there are special type of cells which are insulin producing cells we call them beta cells they release insulin in blood and then this insulin is taken to other cells where it can do its function such substances which are released by certain cells into blood and they act on distant cells we call them hormones blood is also working as a transporter for the hormones or different enzymes or even antibodies within the body for example antibodies which fight with infection they may be produced by produced in a lymph node right they are released in the blood right and those antibodies will be transported through the blood to those sites where they are needed right so what i’m saying that they are also involved in the transport of yes yes certain hormones even proteins liver produces proteins synthesizes and releases proteins in blood and these proteins will go to many tissues right so specifically i should mention hormones some enzymes and like antibodies which are the part of the immune system not immune cell not only it circulated system circulate the immune cells and transport where they are needed even antibodies which also help part of the immune system they are also transported through the blood and hormones or enzymes which are substances which might be produced by one group of the cells and some of these are relay and they are released into circulation and through the circulation they are transported to another group of cells or where they are acting so what we have seen up to now that cardiovascular system not only transport the nutrients not only transports the oxygen and carbon dioxide and other metabolic waste it also transports the immune components like immune cells and antibodies even a transport sub those substances which are secreted by released by one group of cells into blood which act on other group of cells within the body like enzymes or hormones right then any other function which cardiovascular system can have yes cardiovascular system cardio cardiome heart which maintains the pressure so cardiovascular system is responsible to maintain the pressure in the circulatory system right we call it maintaining blood pressure cardiovascular system is also responsible for maintaining maintenance of length of blood pressure right yes then any other function comes in your mind cardiovascular system has some yes more functions like thermoregulation thermoregulation mean uh temperature regulations for for example in humans if you go into very cold weather what happen blood vessels which are coming to the near the skin they will constrict they will shrink they will bring less blood to the surface so that body should not lose the heat you are understanding what is happening cardiovascular system is also involved in thermo regulation for example in very cold weather alteration in cardiovascular system is that vessels or blood vessels which are very near to the skin they shrink they constrict and blood flow near the skin become very less so you don’t lose the body heat or when you are in very warm temperature environmental temperature is very high then what happens blood vessels on the near the surface of the skin they dilate right they bring more blood on the surface near the not on the surface in the skin or under the skin so that more heat can be lost and body temperature does not go up again i will say that cardiovascular system also has some role in thermoregulation maintaining your core body temperature if environment is very cold superficial blood vessels which are very near to the skin they will shrink so that less blood flow to the skin and less heat is lost from the skin and if temperature is very high outside and it threatens to increase the core temperature of the body blood vessels on the skin will dilate and then what will happen more blood will come to the skin and more heat will be lost right so we can say that it has one more function here that it is involved in thermo thermo regulation right any other function comes in your mind yeah sometimes cardiovascular system can help you to attract someone you know you have seen some girls blush when they see their beloved vessels dilate on the face i will not give example of vessels dilating somewhere else but any on the face blood vessels dilate you know there were they were the time girls used to blush now it’s less often so what they do they put the blush on yes they put the blush on okay anyway so this was the sum of the functions of cardiovascular systems these are some of the functions of cardiovascular system okay now let’s go into little detail of that ok before we go into further detail of circular or types of circulatory system let me talk about types of the vessels very briefly you know this lecture is just an introduction to the heart and circulation i’m repeating again again this lecture is just basics introduction right so all these things will be discussed in details later in other lectures in the coming lectures but we right now we talk about that types of vessels now let’s suppose this is your pump hypothetically i’m bringing this pump here this is the pump pump is hard right and this is your circulatory system a very simple circulatory system i’m making is that right now let’s suppose heart is pumping these are the vessels which are bringing the blood to the heart those vessels which bring the blood to the heart these vessels are like yes they are called veins so what are veins veins are those vessels in the body where blood flow is towards the heart right they are bringing blood towards the heart right and now these are the blood vessels they are take taking blood away from the heart because of course if veins are bringing the blood to the heart heart will squeeze the blood pressurize the blood and with pressure throw into outgoing vessels these are veins are incoming vessels heart will receive the blood and squeeze the blood when heart complex contracts when heart power chambers contract they will squeeze the blood and pressurize the blood and throw it into outgoing vessels under higher pressure and these vessels will take the blood to the tissues let’s suppose these are the other tissue cells these cells are very happy why they are happy because they are having a very very functional cardiovascular system now these vessels which are taking the blood from the heart from the heart towards the tissue these are called arteries what are they called arteries right so these what are arteries arteries are those vessels where yes where blood is flowing away from the heart towards the tissues away from the heart towards the tissues and of course blood there will be under higher pressure arteries should be having higher pressure and if they are having higher pressure their walls must be strong their walls must be strong so arteries are usually yes again i will repeat arteries are those vessels which are taking blood from the heart towards the tissue under higher pressure under relatively higher pressure and they have thick walled the relatively thick wall and narrow lumen their lumen this is lumen this lumen is narrow right this new luminous narrow right so this is this is basically artery so if someone asks you what is artery just tell that any vessel which is taking blood from the heart towards the peripheral tissue that’s it that is artery and what is vein vessels which collect the blood from the tissues and take it to the heart right so if this is my heart the incoming vessels are incoming vessels are veins and outgoing vessels are arteries is that clear now once the vessels for example arteries as they are moving away from the heart they divide into smaller branches right what happens that arteries divide into smaller branches and let me show you this part of the arteries this big artery is dividing into smaller branches right now these major arteries these are major arteries they go into smaller arteries and eventually they become very very small they become very very small yes now look there are major arteries they divide into smaller arteries and they divide into very small vessels which are called arterioles what are they called arterioles so what are these rt rules again major arteries yes then smaller arteries and they divide into arterioles is that right now these arterioles further divide they further break down and they for example i take one arteriole this arteriole they break down into many well smaller vessels and these vessels yes very thin world remember arterioles are having lot of muscles they are having lot of muscles smooth muscles and these are circular muscles arterials have lot of muscles right so when arterials have so much smooth muscles it means whenever the smooth muscle contacts they can become very narrow and when they are whenever their smooth muscle relaxes they become very wide arterial they have lot of smooth muscles so they can constrict or they can relax it means if they construct they offer the resistance to the blood flow they offer the resistance to the blood flow and if they offer the resistance to the blood flow we also call them arterioles are also called resistant vessels or resistance vessels water vessels resistance vessels advantage of this is let’s suppose these are two arterioles this this is one arteriole and this is another artichoke suppose some tissue is here this is tissue a this is not cell of course there are many cells in around but and this is okay we just talk about part of the tissue let’s suppose this is some tissue it is having two arterioles this part is metabolically more active it needs more blood supply this is this part of the tissues pose is less active so it needs less blood supply so what arterials will do it will constrict here and it will dilate here so in this way arterioles regulate the blood flow within the tissues and within the body where to take more blood where to take less blood so arterioles play a role in redistribution of blood pattern is that right again all those vessels which are taking the blood away from the heart they are basically arterial system arterial system has major arteries which have lot of elastic tissue they are also called elastic arteries then the smaller arteries and eventually smaller arterial arteries break down into very very small arterials which are very rich in smooth muscle and they are resistance vessels if they have to reduce the blood flow to some part of the tissue they will construct if they have to increase the blood flow to some part of the tissue they will dilate is that right now from the arterioles arterioles will break down in thousands of very thin walled vessels which are called capillaries arterioles break down into very very small vessels and eventually the very thin walled vessels these are called capillaries right these are called capillaries now capillaries now these capillaries these are the cells and you see this is whole capillary bed these are capillaries these are capillaries now what is the real difference between arterials then capillaries very big difference arterial the thick walled do you think oxygen can go out out of the arterial to the tissues no can glucose go out of the arteriole to the tissues no actually arterioles just this arterial tree just bring the blood from the heart under pressure to the tissues right and eventually articulates break down into capillaries which are very thin walled because capillaries are very thin wall very very thin just one cell thick right thin wall so very easily glucose can go out oxygen can go out other nutrients can go out to the tissues they can diffuse out remember blood is itself not going out blood is moving through the capillaries at a very low pressure and very very slow pace blood is moving very very slowly and by simple diffusion or by simple mechanisms substances from the blood and capillaries can move to the tissue cells and waste products from the cells can go to the diffuse into capillaries so basically capillaries are what kind of vessels what type of vessels they are able to exchange the nutrients with the metabolic waste they can give the nutrients and take the metabolic waste capillaries can give the oxygen and take carbon dioxide so we call them exchange vessels what we call them exchange vessels it’s so simple to understand is that right this main artery or smaller artery or arterioles they are not exchange vessels they are just pipe which carry the blood away from the heart but when these arterials break down into millions of capillaries blood in the capillaries flows very slowly why slow movement of the blood gives enough time to this blood to provide the nutrients to the cells and remove the waste product now there is one question why a blood flow here becomes so slow here it was under high pressure as blood is moving from the heart it comes into arterial system it comes under high pressure as blood moves forward especially when it comes into capillaries the blood the pressure with of the blood decreases and velocity of blood the move speed with which blood is moving in capillary also drops i mean blood comes jumping and running from here and here it start a little catwalk where where it is doing catwalk in the capital is why it is doing so slow and stylishly so that if there is some chances of exchanges between the component of the blood and the tissue fluid that should be done right because from the capillary if substance has to go to the cell first of all this will go out suppose this is the cell which is going to receive the glucose first it was in blood then this glucose will come out of the blood into this fluid around the cell second position and eventually it will shift to the cell here it is in position number one is in blood position number two is that it is diffused from the blood or moved from the blood into fluid around the cells this fluid is called interstitial fluid enter station fluid and from the interstitial fluid it will be taken by the cells in the same way oxygen from the capillaries blood is moving slowly right if cells are using oxygen rapidly cells are low in oxygen they will pull the oxygen from interstitial fluid interstitial fluid will become low in oxygen and that will pull the oxygen from capillaries into interstitial fluid in the same way metabolic waste cells are producing more metabolic weights so they will move into where interstitial fluid and from there it will move into blood but this exchange can occur only in capillaries there are many types of capillaries but just believe me that water values capillaries are exchanged vessels but i was asking i was telling that when blood is coming through the arteries it is come jumping and running under high pressure and here it starts catwalk it becomes slow we understand why it should be why it should be slow so that exchanges can go on but the question is what makes it slow when it was coming very what great pressure and with high velocity it was coming under high velocity high speed here it become very slow why it becomes slow who will tell me yes no elasticity no is it the cross section area yes he is saying it has something to do with the cross section but let me explain the other guys and girls what what you are trying to say let me tell you let’s suppose this is an artery this is an artery and this is the cross section of this artery right this is the lumo of this artery or we can say this is a cross section now blood is moving through this area when it uh goes into arteriole suppose these are the two arterioles right from the arterioles it goes into capillaries now look at it one capillary second capability third capillary fourth capillary right here again another capillary another capillary and yet another capillary and yet another capillary now look at it here blood was only in this area the cross section was blood was here because it is just like a narrow river when river is narrow water moves slower fast fast and if river become very wide the water will move slow similar here it is narrow area so blood will under high pressure will move very fast but when it reaches here it divides in so many mil thousands of capillaries thousands of capillaries so what happened the total surface areas of all these capital is very high let’s suppose we bring these all is here here so this is cross section of this capillary okay we bring the add this cross sections of all these capillaries for single capillary for a single capillary its cross section area of the lumen is much smaller than the artery for a single capillary the lumen of single capillary cross section is much smaller than the arterial cross section but because from one arterial system millions of people has come if you add all cross sections right if you add all cross sections together so these are how many one two three four five six seven eight so i will show eight yes now this is the total cross sectional area of capillaries and this was the total cross-section area of the artery so what we have seen that as blood moves into from the heart even though it goes into smaller vessels but number of smaller vessel is so much that total cross-sectional area from major arteries to the capillaries keep on increasing right so this cross-sectional area which was little here has become so much let me make it again that yes i am making capillaries and they are cross sectional areas now you see blood is total cross-sectional area combined of the capillaries which are derived from one artery total cross-sectional area of all the capillaries which are derived from or receiving the blood from one artery here cross sectional area is more than feeding artery so what will happen pressure should go up or down pressure should go down right if we talk about single artery again i will repeat there’s a little paradox if we talk about single artery single arteries of course much larger as compared to the single capillary but because one artery divides into millions of capillaries the total cross-sectional area of the lumen of capillaries combined is far more than the total cross-sectional area of the feeding artery so blood flow become slow not only it loses pressure but also become slow so we can say here the blood was this the river was narrow and it divides into so many small riverlets right so many millions of the rivers that it become very slow is that clear yes so we can say arterial system is usually relatively high pressure system and you drain into capillaries where there is pressure low and arterial system is a high velocity system high speed system and keep inductive rays flow is low so arteries are mainly what is happening just bringing the blood from the heart to the tissues where arteries break down into smaller arterioles into eventually capillaries and these are the capillaries which do the real exchange these are the capillaries which do the real exchange of nutrients and metabolic waste now these capillaries come together these cripplings come together and they drain into yes another group of vessels and these small vessels are now collecting the blood from capillaries this vessel and this vessel these vessels are collecting the blood from capillaries these are collectors these were feeders providers they were bringing the blood they’re collecting and these collecting vessels right they also fuse with each other and yes these vessels in which capillaries are draining if i am the capillary if i’m the capillary i’m receiving the blood from which side arterial side and i’m draining into venous site this is venous side because it is now taking the blood towards the heart circulatory system circle [Music] right so in this circle what is happening circle is starting from the heart in this example right heart is pressurizing the blood pushing into arteries which are high pressure system high velocity system as arteries break down into smaller arteries into arterial that eventually millions of people is pressure and velocity both drop and triple leaves are very thin exchanges occur right so and then from blood from the pillars which has lost some oxygen and gained some carbon dioxide lost some nutrients and gained some metabolic waste right these capillaries are connected to the collecting system which will take the blood back to the heart it means these capillaries on the other end on the draining end they are connected with the veins they are connected with the veins now here what we can see as we say these are arteries big arteries then into smaller arteries and then arterioles then kepler is now reverse will occur here first blood from capillaries is taken into smaller veins very small veins are called venules what are the spellings of venues i cannot hear v okay let’s hope you are right otherwise correct yourself from google or something like that news okay thanks god you are awake okay venues so what we can say from blood from the capillaries is collected into venules venules join together and make small veins then large veins and later on we’ll see very large winds which are called vena cava which will drain the blood or bring back the blood to heart so this is the basic basic design of circulatory system we will discuss in detail later on there is single circulation there is double circulation there is and we’ll also talk about open circulation and close circulation that is for the later lecture right now i just wanted to tell you the basic concept about vessels again if i’m the heart i’m taking the blood to the tissues so what is this artery and from here i’m bringing the blood to the heart what is this veins and these are capillaries it means capillaries on one’s end are connected with arterial system from where they are receiving the blood and capillaries on other end are connected with the venous system where they are draining we can say capillaries are very thin walled exchange vessels which are interposed between the arterioles and veneers arterials acting as their feeder and venules acting as their drainage system right yes any question up to this just i want to understand yes yes you have a question is there any artery that brings blood to the heart okay he is saying there’s any artery which brings the blood to the heart very good question listen the question is when i say arteries are taking away blood from the heart i mean that arteries are taking the blood away from the chambers of the heart from the chambers of the heart towards the tissue towards the tissue and when i say veins are taking blood to the heart it means they are taking blood from the tissues collecting from there and draining it back and bringing into heart so that heart can again pressurize because when your question was is there any artery which brings the blood to the heart no there are arteries which bring the blood to the wall of the heart there’s a difference okay now let me put this as a heart let’s suppose this is your heart four chambers now these are the walls of the heart ventricles are very thick walled these are what walls of the heart right now anything which is bringing the blood into heart is when anything which is taking the blood out of the heart is artery but if there is a vessel which branch from the artery let’s suppose there is an artery which is going out and this artery let’s suppose i show that there is an artery going from here to the tissues right but from this artery if there is a branch which is taking the blood to the wall of the wall of the heart right will still say this is taking blood from the heart towards the wall of the heart right this is called coronary artery this is called coronary artery what are coronary artery coronary arteries are those arteries which are bringing the blood from major artery coming out of the heart heart pump the blood into major artery which is called aorta we will discuss this in coming lectures we will discuss this in coming lectures when heart pump right specially in human beings if i’m talking about left heart left ventricle it pump the we’ll discuss in detail in later lecture right it brings the blood into aorta from the aorta some smaller vessels come to the heart especially too those two which bring to the heart we more accurately bring the blood to the wall of the heart right to provide the nutrition to the wall of the heart because wall of the heart which is contracting requires a lot of oxygen and nutrients those are called coronary artery but for practical purposes for right now you just remember that if on the heart this is what major is if it is taking the blood away what is this arterial system arterial system major arteries smaller arteries arterioles and then capillaries connected to arterioles and this is the collection system which is bringing the blood back to the heart yes capillaries connected to the venules venules smaller veins larger veins back to the heart is that right now i will just see you have understood or not that if this is hard this is hard this blood vessel is taking the blood out of the heart to the tissues what is this major major artery divide into smaller arteries divide into very small arterioles divide into capillaries which are exchange vessels right yes and then capillaries now they are not dividing they are fusing together they are uniting together making venues and when you unite together to make small veins then larger veins and back to the heart and circulation is that right yes so let’s have a break