 back to the NPTEL lecture series on animal physiology. So, we are in section 6 about the blood cells immunity and the clotting. So, initiated with the red blood cells in the first section and then in the second section I bypassed the white blood cells and moved on to the bloodlets and the clotting factors. So, today what I will do I will tell some of the basics. Now, since you have fairly good idea about what blood is about some of the basics what whenever you go to a doctor and the doctor ask you to get a blood sample and a blood testing and what you see in the sheet. So, you know the doctor takes the blood or the compounder takes the blood and then it will be processed and next evening or the same day or after sometime you see a report. So, what that report really says and how you can interpret that report this is very important for you to understand this is the practical aspect of it and next thing what we will be doing I promised you that I will be covering how this different blood cells are formed how this whole differentiation process how a one single cell. So, let me rephrase this sentence essentially blood is formed from one single form of you can call it a pluripotent or stem cell or something of that that kind. So, from one source it all divides some forms following a different pathway red blood cells some forms white blood cells some form platelets how that whole thing happens. And one more thing in my last class while I was teaching about the platelets I made a small mistake just correct it I talked about the thrombocytes. Platelets are not actually the platelets of the of the human being or mammal it is for the non mammalian. So, the thrombocytes are those just slight error basically platelets are formed from mega karyocytes I will come to that just correct that small error which I made in my previous class on the clotting aspect. So, talking about the blood what a doctor does when doctor ask you to do a blood analysis. So, blood is a fluid that we all know by this time we know that it is flowing all over the body. And fluid has lot of particles those particles could be cells we have talked about red blood cells which are carrying the oxygen. Then we talked about the platelets they are also small teeny tiny particle of 4 micron kind of a major diameter or it is kind of triangular shape. So, you cannot call it a major diameter it is kind of if you take the maximum length of that triangle the kind of the base of the triangle then probably it will be around 4 micron. And those are non nucleated same way the red blood cells are non nucleated they do not have any nucleus apart from I talked about the platelets that is why the thrombocytes come thrombocytes are the platelets of the non mammalian system which indeed have nucleus in them. So, we are not going to deal with that those thrombocytes will be only dealing with the platelets which are in the human system. So, and then you have the third cell type which is white blood cells the cells for immunity the macrophages. We talked about the macrophages why we talked about how the red blood cells which live their lifetime of say 120 days or 110 days kind of rejected out of the body how they are being engulfed by the white blood cells in the macrophages. So, the macrophages if you do something called a blood smear. So, what essentially is blood smear is that say for example, in my tip I just prick it and get a drop of blood and make a smear. So, you take the drop of blood and put it in a glass cover slip and you just you know spread it like this just like you have a drop of water you do it like this like look at my hand and if this the glass cover slip is just a smear it and if you look at the smear then there are several kind of once again excuse me. So, if you look at under the microscope you will see three distinct features one you will see I told you about this platelet cells we do not have any nucleus. So, if you add any nuclear stain you would not find any nuclear staining on them then you will find some cells which are circular by concave kind of cells which also do not have any nucleus those are your red blood cells. So, there may be some red blood cells in the phase of formation which also does not have any nucleus yet you will find a kind of cell or a series of such cells which will have multiple nucleus connected to each other which are multi-nucleated those multi-nucleated cells are your white blood cells. So, if I have to draw this the classification of it it will look something like this on a blood smear you will see. So, if this is your glass and if you are looking at a smear you will see something like this and then you will see something like this you will see a huge, huge cells with this now look at this and going by the dimensions if you look at it these huge cells which I am now circling in red these are your WBC's these one which I put it in green are the little it is and the one I am now putting in yellow are your RBC's this is what you can see it under the microscope in a blood smear yet these are the cellular component, but your blood is fluid and what is the fluid component. So, if say just imagine and in that smear if you have a very high resolution microscope you can see proteins just imagine for the imagine it is like you cannot really see it under like that with the known technologies then you will see a series of such proteins which are present there and they are kind of floating in the fluid which is mostly water. So, this watery fluid on which this proteins are suspended and the cell component are two different aspects. So, they are two different aspects of the blood. So, the blood essentially if you if you have some way say for example you take the blood sample in a in a in a tube like this just for your visualization say for example I give you a tube like that and here you have filled with blood. So, this is all red is the blood now if you if you take this blood and you spin it at certain rpm you put it in a centrifuge and spin it after sometime what you will see after you spinning spin it down this is what you are going to see this is spinning or centrifugation is done to separate out components within a fluid. So, what you essentially see the fluid component remains at the top and the cellular component or the solid component comes at the bottom there will be separation and separation will look pretty much like this. So, what you see is lot of solid component here and here you have a lot of fluid component. This fluid component which you separate out is called plasma this cellular component all is this you can call it a cellular component or it is technically it is called formed elements and this formed elements are nothing but what I showed you here these are the formed elements WBC's RBC's and plate. So, now put the name for that formed elements and if I have to do a volume percentage ratio for this this form elements are around 37 to 54 percent that is the constituent of the formed element whereas, the plasma component out here this plasma component varies from 46 to 63 percent. Now I talk to you about the different formed elements now I will talk to you about the different proteins which are present there and these proteins are essentially called plasma proteins. So, that form the plasma component consist of protein elements. So, which you can imagine as if cell is a bigger particle which so protein is a micro nanoparticle. So, macroscopic particle at the micron range and you have a nanoparticle. So, those nanoparticles remain suspended in the fluid and the fluid consist of lot of electrolytes. So, plasma can be now put into two component plasma protein component plasma electrolyte component. So, that is what we will do now let us classify the plasma out here plasma into two parts one part is called plasma proteins this plasma protein the major contribution is made by albumin albumin you all of you are aware of that in the this is one of the major egg protein you see that in the egg you have this albumin protein bovine serum albumin and all this albumin. So, albumin is one of the major chunk which is approximately almost I think around 60 percent of albumin apart from albumin in the clotting I highlighted that you will be needing fibrinogen fibrinogen is another component which is present there then let me enumerate them albumin which is approximately 60 percent then you have globulin proteins hemoglobulins that these are the globulin protein which constitute 35 percent then you have 4 percent of fibrinogen and you have a bunch of enzyme pro enzyme hormones. So, which essentially falls under regulatory proteins which is around less than one percent. So, this is pretty much the protein component which is involved in it. So, you have the huge chunk of the albumin globulins fibrinogen and a series of hormones and pro enzyme and everything and this concentration of these different protein varies under different conditions of your body different physiological status of your body different pathological status of your body. So, by looking at the blood sample analysis of the blood sample could tell with what kind of technically speaking one can predict cancer by very early diagnostics, but where is the problem why we unable to detect it this is the challenge the reason we are unable to detect it lies in that last less than one percent regulatory protein I just telling you all the hormones enzymes pro enzymes and everything because it is exceptionally challenging to you know I should say estimate proteins at a very low concentration it is a big challenge it is a enormously big challenge because and what level is higher than normal is another challenge to figure out because whenever cancer or any kind of pathological situation happens it is not that those proteins though they are already present in the body, but because of some x y z wrong situation their level either goes up or goes down, but how to make that demarcation because already these proteins are present in proteins and enzymes are present in such a such a low concentration they work at a it is a very low concentration chemistry thing call about it is a very femto nano femto likewise that molarity at that molarity these things are working. So, at that concentration it is really really tough and it is across the globe whether you talk about N I H United States whether you talk about other similar organizations in Europe back home in India all the places is still blood always remain one of the hot subject of research could we analyze all the component and far more early before the we reach to a point there is no point of no return that time you know you cannot read the patient will die of that problem. So, could we diagnose it is there a way to diagnose is there a way to diagnose cancer way early is there a way to diagnose some neurological disorder way early by just doing a blood sample could we predict do we have any mode how low we can detect it is all about the detection limit and how accurately we could we can detect, but what is the level of accuracy that is very very important. So, that is why I highlighted this that was the reason why I wanted to highlight this point those less than one percent do not neglect them they are exceptionally important because that is where lies all your diagnostic kits diagnostic tools and everything. Now, let us move on to the other component of the plasma. So, we talked about all this smaller particle component which are at the nano not only at the nano I mean like the at the nano size domain now let us talk about the pure elemental composition in the form of the electrolytes let us get back to the slides and once again the other solutes include your electrolytes which of course, you have sodium potassium calcium magnesium chloride bicarbonate phosphate sulfates likewise 2 plus 2 plus minus these are the series of electrolyte then you have the in this fragment you have the organic nutrients which includes your ATP cholesterol. So, this is another one fatty acids then you have carbohydrate you have amino acids likewise and then you have the organic waste it carries which includes your urea uric acid creatinine bilirubin ammonium ion. Now, having enumerated this that is I will request it all of you see whenever you get a blood profile check what all the doctors can tell you doctors can tell you get me the the possibilities the doctor can tell you I wanted to see a blood cell profile if the doctor ask for a blood cell profile what are the possibilities either the RBC profile they will doctor is asking or a WBC profile doctor is asking or a platelet profile doctor is asking if the doctor is asking for a platelet profile it means doctor has a suspicion about your clotting may be there is excessive clotting or you know there is a lesser clotting may be something related to hemophilia or blockage in somewhere in the vessels. If the doctors talks about WBC's then it has something to do with immunity fine if the doctors talk to you about RBC it has something to do with oxygen carrying capacity are you anemic or you are hyperactive or you are carrying more oxygen. So, look at it from one simple fluid these are the three aspects now if the doctor ask you I want an uric acid profile or I wanted to know what is the urea or ammonia that essentially means doctor is doubting you know how your kidney function is because urea and uric acid this is all secreted by that by that through the kidney. Now if the doctor ask get me the potassium profile this is very interesting when the doctor ask for potassium profile doctor may suspect that you may have a some clotting problem because if you remember I was telling you that potassium plays a very critical role in all kind of clotting mechanism. If the doctor ask you that I want like you know profiles like electrolyte profile and doctors may suspect that you know your electrolyte exchange is being compromised then doctor may ask you I want a lipid profile this is also doctors will ask you just give you give a blood sample you will get a lipid profile. Then the doctors are aware of are easier color stroll is within control or is the good color stroll and proportion of good and the bad color stroll are they balanced to balanced in an optimal zone or you are at the danger zone you are at the susceptible zone for heart attacks or any kind of other disorders they may ask for a lipid profile. So, look at it from one blood sample you can predict almost I just I mean randomly I could tell you at least 50 different situations which could happen in your body because always realize whenever you study physiology always is very holistic thing this whole blood is flowing all over your body it is not only picking up the element which it has to throw away from the body the organic waste it is also circulating the important compounds with the body needs for its growth survival and maintaining the homeostasis as well as hemoestasis hemoestasis the clotting and homeostasis is the complete balance of the body. So, that is why blood analysis and blood sampling is so very important doctor first thing doctor will say or if the doctor suspect diabetes I want the fasting sugar non fasting sugar. So, try to look through look through any of those like the blood reports and see on one column you will see what the what the analysis has told you on the other column they will see this is the control this is the maximum allowed minimum allowed zone and this is the normal zone and then you have to correlate where your value falls in terms of you know the blood cell count or carbohydrate what is what then doctor may tell you I want the bilirubin profile or the bilirubin concentration that is why doctor is basically essentially indicating doctor is suspecting you suffer from jaundice you know. So, these are some of the things which a blood analysis can tell you and that is why after giving you some bit of an introduction about the blood red blood cells and the blood let us I came to this topic that will help you to appreciate why are we studying it in depth. Now, what I will do after covering this part of the basic the whole idea of blood testing and diagnostics and everything what I will do I will move on to the way the blood cells are formed. So, I will try to cover it in one slide with a pictorial representation how within the bone marrow from one single cell type all the different cell types are getting differentiated the left most column we will be talking about the red blood cells are we talking about the white blood cells then we will be talking about the blood let us. So, in a one slide this is how I am planning it that will take care of all your doubts how these are being formed. So, let us back to the slide and talk about the origin of the or the basically the origin and differentiation of formed element origin and differentiation the process by which a cell attains its final fate differentiation of the formed elements. So, it starts with something called hemocytoblast it is a huge cell though it is a nucleus hemo means blood hemocytoblast this is the beginning point in the blood marrow in the in the bone marrow hemocytoblast divides into two parts cytoblast part of it form lymphoid and myeloid stem cells lymphoid stem cell and part of it form myeloid stem cells myeloid stem cell I will just put s c hence forth because that will help me is. So, then this myeloid stem cells under the influence of factor called multi CSF they form certain elements called and of course, there are few other molecules which are involved in it which is called erythropoietin EPO erythropoietin the influence of EPO some of these myeloid cells form the precursor cells for. So, this is the zone where we will be talking about all the RBC formation. So, let me put it in red. So, these are the progenitor cells for the RBC this is an put it like this RBC progenitor cell. So, this is where the RBC progenitor cells are forming and there is another series of progenitor cells from myeloid air forming I am putting them in green progenitor cells. These progenitor cells form something called mega karyoside and these mega karyosides are cells like this huge huge cells like this. So, what I will do before I come back to the right side like all the all the lymphoid stem cells and all other things what I will do I will just talk about these two elements I am just putting them in these two elements we will talk about first otherwise it will become very complex we will talk about these two elements the what is happening here. So, let us first of all talk about what is happening to the RBC progenitor cells. So, we start with after the. So, the first series of cells are called pro erythroblast this pro erythroblast this pro erythroblast reached into erythroblast stage erythroblast is the other name for the RBC erythroblast and from here it form something called reticulocyte and reticulocyte is the phase when it starts losing the nucleus which you remember I was showing in the first class how they are losing the nucleus because of 15 lipoxygenase activity. So, this is the zone where the reticulocyte is the stage when from erythroblast to reticulocyte formation this is the stage when there is a sharp peak within the cytoplasm of 15 lipoxygenase enzyme which I have already discussed in the first class and because of that 15 lipoxygenase enzyme all the different cell organelles and the nucleus completely gets damaged. So, the cell is only filled with hemoglobin molecule which helps for rest of its life of 120 days to carry oxygen from reticulocyte what we get is essentially the RBCs. So, this is the pathway which is followed which started with if I had to summarize it started with hemocytoplast then you have myeloid stem cells from myeloid stem cells because of the influence of erythropoetin some of these progenitor cells these are the progenitor cells. From pro erythroblast and pro erythroblast become erythroblast then erythroblast becomes reticulocyte and that becomes RBC. So, we had done with one set of reactions which leads to the formation of the RBCs now what we will do we will talk about the second one which is the formation of the platelets or the clotting elements of the body. Let us get back to that so what is happening here. So, same again starting with hemocytoplast hemocytoplast to myeloid stem cell the myeloid stem cells under the action of multi CSF which is multi CSF stem stands for colony stimulating factor is myeloid stem cells from progenitor cells for progenitor cell for which are destined to become platelets progenitor cells for platelets and then they form a structure huge structure called mega karyocytes. Of course, the mega karyocytes it has nucleus mind it mega karyocytes and this mega karyocytes then divides into small cells the platelets. So, this is the second root by the stimulation of the myeloid stem cells by colony stimulating factor these cells form a huge cells called mega karyocytes then mega karyocytes started fragmenting they basically as I told you platelets are fragments of a bigger cell they do not have any nucleus at least in the mammalian system in the non mammalian of course, in the thermocytes they do indeed have, but that is a totally different mechanism and we are not going to discuss this here. So, these fragments of the cells form the platelets. Now, we come to the much bigger and the tougher one which is how our immune cells are formed because as of now we bypassed all that we talked about RBCs we talked about the platelets. Now, let us get back to that whole hemocytoblast and we talked about the lymphoid stem cells and I have not talked about. Now, I am going to talk about part of the lymphoid stem cells and part of the myeloid stem cells and how they are leading to the formation of the different white blood cells which are almost 5 types eosinophil, basophil, lymphocyte, leucocyte likewise let us get into that. So, move on to the next slide. So, again we start with hemocytoblast. Now, let me use other color hemocyteoblast. So, I showed you the one classification on the one division on the side because they form lymphoid stem cell and lymphoid stem cells form something called lymphoblast and lymphoblast form something called pro lymphocyte, pro lymphocyte forms lymphocytes. This is one root, there are multiple roots which I am coming to the next. So, this is where all the lymphocytes are forms. So, white blood cells could be classified into two groups. One group which has the lymphoid lineage they form from hemocyteoblast to lymphoid cells and then through cascade of lymphoid stem cells to lymphoblast to pro lymphoblast and reaching all the way to lymphocytes. The lymphocytes are further classification which I will be coming soon lymphocytes could be B cell T cell likewise I am not getting into that at this point. So, this is one root which is the lymphoid root, but I showed you that this is another root which is myeloid root. What is happening in the myeloid root? What they are responsible for because already we have seen when hemocyteoblast is divided into myeloid root it leads to the formation of RBC's and the platelet. Yet a part of this myeloid stem cells do form other components of the white blood cells. So, we will now discuss the second root. So, hemocyteoblast to what I will do I will just pick up another color so that that will make your life slightly easier to understand. We have already talked about two roots where hemocyteoblast let us do it like this this is the wrong way to show it fine. Here let us put the myeloid stem cells myeloid stem cells from myeloid stem cells. I talked to you that through erythropoietin something is from RBC's this part is all taken care. Then through colony stimulating factor some of the cells are forming platelets this part is all done. So, we are not going to deal with this part now we will talk about what is happening to the myeloid stem cells then out here. So, some of these myeloid stem cells are and this influence of GM and CSF colony stimulating factors to progenitor cells which are destined to become white blood cells progenitor cells for WBC white blood cells. These progenitor cells then divide into two parts these are called one part they are they all fall under one part which are called blast cells these are called myelo blast myelo blast this myelo blast further form three kinds of myelocytes. These myelocytes then form something called band cells and this band cells form three different white blood cells one is called basophil the other in one is called eosinophil third one is called neutrophil. Whereas, there is another root I showed you there is something which form here is from myelo blast is from monoblast this monoblast form then called progenitor monocyte and pro monocyte form monocyte. So, this is the other root which is of course, separate it out at this point this is the demarcation taking place this is where the two different cell types are getting separated from here this is one type one separation this is second separation and this is the second root. So, in some total your basophil so if you look at it what are the different kind of white blood cells you have basophil you have eosinophil you have neutrophil you have monocyte which are coming from myeloid lineage and you have lymphocytes which is coming from lymphoid lineage. So, some in some in some total there are five different kind of WBCs now if you in the light of this information if you look at the blood chart when the doctor ask you that get me the blood report they will say eosinophil concentration is higher. Generally, whenever you have persistent sneezing or something doctor say oh you are suffering from eosinophilia what does that mean that means your eosinophil cell number has gone up these eosinophil what you see I which I draw which has coming from myelo blast and myelocytes and the band cells and if you look under the microscope how they look like they look something like this all these different now I am talking. So, basophil looks like this there are lot of pig a lot of pigments all over the place and if you look at eosinophil eosinophil cells will look like this something like this. So, this is eosinophil this is of course, they have to be put different kind of dies in order to color them then if you look at the neutrophil the sizes are fairly close to each other I mean these are all multi nucleated cells. So, this is called neutrophil then you have monocytes which is more compact kind of you know this is monocyte and of course, lymphocytes also slightly smaller though like this which is lymphocyte. So, coming back so if I had to summarize it. So, we talk about hemocytoblast and myeloid origin hemocytoblast divided into myeloid lineage lymphoid lineage myeloid lineage leads to the formation of RBCs let let us and basophil eosinophil neutrophil monocyte which are all clubbed under the category of white blood cells and there is another set of white blood cells which are of lymphoid origin which are formed by the from the lymphoid lineage which are called lymphocytes and lymphocytes are further divided whatever we will do now after telling you this I want you guys to visualize whenever you heard about somebody has a blood cancer what really that means. Now, in the light of this whole differentiation what I highlighted in the bone marrow what is happening from hemocytoblast think of it how tightly this whole process is regulated each cell number has to be right if it is wrong then there is a problem each cell number has to be has to be tweaked in such a way that if something goes bad you may suffer from hemophilia you may suffer from clotting disorder you may suffer from anemia the oxygen or you may suffer from or you may have higher oxygen carrying capacity if you are fortunate then you will be very hyper hyper active you may have more number of more you may be immune compromised aids your immune compromised. So, immune compromised means your problem with your white blood cells. So, in the light of this whole differentiation process from how from the hemocytoblast this whole differentiation of blood cells is forming all throughout your life within the bone marrow that means there is enormous research is taking place across the world to understand this process because this is that zone where lies some of our answer to cancer because if you have to understand cancer this is where we have to hit upon one of the of course related to the blood cancer this is why it is because this whole differentiation is very very tightly regulated I mean like you know there is one flaw from it is the person suffers. So, that was the sole reason why I took this whole class single like in a exclusively to give you in the light of this when you look at the whole thing that will make more sense to you then looking them at you know small fragments bits and pieces. So, that is why the blood analysis is so very important that you know what are you analyzing in the form of blood that is the sole reason why I just started with your RBCs talk to you about the clotting and then came to and introduce you to the whole lineage of WBCs how they are formed it is from the same cell. So, what regulates some of the open ended questions which remain which are to be answered by mankind is that what it is so unique from the same population of cell some becomes RBCs some became neutrophil some became platelets could be. So, the future of tissue engineering future of differentiation development biology is that could I pick up any cell any blood cell or those kind of progenitor cells like hemocytoblast and say I need more number of platelets or I need more number of RBCs and could you put it back that is the translational medicine where it is all heading could you do that that is the future where it lies could we control the differentiation of the development of these different kind of formed elements and if we could know how we could this is where lies some of the very very challenging questions of next century of this century as a matter of fact that could we really do that could we cure could we cure a patient of blood cancer that you know we know do not worry we can take out a cell or it is another way could we take any kind of stem cells and transform them into blood cells or any other cell type. So, these are some of the very open ended questions which for which the blood is driving all over the world the scientist are working day and night to figure out some of these answers because it is very easy to see the chart and the fact is physiology is far beyond those charts how really to do that yeah of course this is only bits and pieces and if you look at if you go back to this go back to this chart what I was trying to draw and show you guys think of it there are so many factors which are involved which about which we have no idea which are really leading to this what is leading to this what are the signal. So, that is where lies a lot of unanswered questions out here or say for example, here proethyroblast erythroblast erythroblast reticulocyte there are so many factors what are those factors and those are happening at a those are very small molecules they are expressed for a moment and that is it they moved out how we can control differentiation these are some of the questions and that is why that whole chart I wish you guys to redraw that chart in a bigger paper so that that because because there is a size and limitations of this screen that I cannot draw everything unless I am in a blackboard where I can have the whole end. So, I want you guys to you know redraw this whole thing what I have covered now as of now that will give you a kind of understanding how this whole process is taking place. So, what I will do now probably in the next class what I will be doing is that will be talking about the function of the different WBC's and we will talk about little bit of the immunity and little bit about the R H factor there are couple of things which I have not touched. So, let me tell let me tell you what I will be touching in the next class I will be talking about the blood groupings that you guys have heard this A plus B plus O and what is blood grouping really that is one aspect what I am going to touch second I am going to touch about little bit of a immunity third I am going to touch about all the all the all the different kind of WBC's which are present. So, all the different kind of WBC's blood grouping and bit of an R H factor R H positive R H negative and how that influences the pregnancy we will talk about all these things and little bit of a immunity and that is why we will close in with this section of blood cells immunity and clotting thanks for your attention.