ABO Blood Group System - Blood Types & ABO Antigens

today we are going to talk about blood group system remember there are so many blood group system right they are more than 30 major blood group system and there are hundreds of the minor blood group system but as far as clinically relevance is concerned two blood group systems are most important two blood group systems are most important number one is system and number two is Rh system today we are going to focus and work on blood group systems right now to make a very fundamental concept that what is this group I will start a simple example that we have a person here who has blood group a and we will talk about why we call that person with blood group a bi did you come here now this is a man and of course I'm sure he's a man so his blood group is blood group a right now when we say that here the blood group a it means if I draw his circulatory system if I draw his this is a circulatory system if I draw a circulatory system the circulatory system should have such type of red blood cells red blood cell can be drawn like this or like this depending upon you are looking from the side or from the top if I say this person has blood group a it means that his red blood cells have special antigens which are called a antigens what are they a antigens with red blood cells are loaded with antigens yes a antigens right of course I will explain very well what is meant by the a antigens right and if I say there is one more person and his blood group is B right if I say there's another person let's suppose to talk about mister is ass yes come here he claims that his blood group is B and if his blood group is B now you can understand then his red red blood cells should be having what kind of antigens be right you should have which antigens be antigens right so it means those people whose red blood cells have a antigens they are considered blood group a and those persons who have B antigens on their red blood cells they are considered blood group B I will explain in detail what is a antigen and what is B antigen and then we take the third person and this person has a and B both antigens present on his red blood cells that this person has a antigens and not only a antigens on the RBC's but this person is having B antigens as well right so he has both categories of antigens on all this red blood cells and this person should be called which group a B group what is this called a big group so here is a drupe this is yes d drew and this person is a B blood group is mind blood rope so we can take my example and this is a be blood group then we come to a situation Jess we have one more man here and he claims his blood group is oh and if we think that his blood group is all then which antigens are present on his red blood cells a or B which antigens are present no antigens simply no antigen what do you think yes this person's red blood cells they don't have a and they don't have B but they do have something else they are not really bald like me they have something else what is that they are not naked red blood cells of course they don't have B antigen they don't have a antigen but still they have some time they have an TA and TB he made a mega mistake remember blood groups are decided according to the antigens not antibodies so don't tell me n TA and TB that we'll talk later that will talk later but blood groups are basically named in a B of system in a Bo system blood groups are given the name according to the presence or absence of a or B specific antigen if only is present a group if only B is present being group if both of the antigens are present these are antigens these antigens are then a big group but what antigen is present over here yes have a seat and anyone who can tell me here yes so many intelligent people sitting here I agree with you that this person who has blood group oh he does not have a antigen he does not have B antigen but he still has something on his RBC's his RBC's are not naked not bald or we can say not nude they do have something on them so what is that o antigen I think I will refer to it as H substance H substance or H antigen no I need to explain now H antigen has a very very intimate relationship with a antigen and B antigen let me explain first of all I will explain what is H antigen then I will explain how a H antigen in the red blood cells is converted into a antigen and some peep and converted to be antigen in some other people right so let's come from where these antigens are originating let me take a big red blood cell okay I will come over here first I will explain the age this is precursor of red blood cell this is a precursor of red blood cells because to make such antigens we do need enzymes and enzymes and proteins are derived from the activation of genes DNA and RNA and then protein synthesis right but you know that RBC do not have nuclear material a mature RBC does not have any nucleus these are a nucleated cells is that right if our visas are a nucleated cells how they can produce such antigens answer is that these antigens either h antigen or a antigen or B antigen they are made on the surface of precursor cells with robotic precursor cells when it switches is going on those cells those like retro blast and then there are series go into normal blast and different series eventually reticulocyte and then red blood cells these precursor cells the precursor cells of red blood cells do have nucleus they do have nucleus let's suppose this is a precursor cell this is a precursor cells was a little blast or normal blast which is eventually going to convert this red blood cell with each substance so I will tell from where this each substance come right now I'm going to explain from where this aged substance comes let's suppose here is your nucleus and there are different type of chromosomes there right now first of all there is synthesis of synthesis of oligosaccharides which are planted on the surface of cells what are these oligosaccharide what is the meaning of oligosaccharide oligosaccharides are short chains of monosaccharides of simple sugars for example this is an oligosaccharide there's one sugar than another sugar than another sugar and then another what is this monosaccharide once somewhere between two to ten monosaccharides when they are made a chain this chain is called oligosaccharides now first of all RBC's all are right they are having these oligosaccharide precursor molecule what is this precursor molecule and there are millions of such molecules on each red blood cells about two millions the millions of such molecules on each red blood cells but for explainatory purpose i will just mention one or two molecules so i'm showing it here that here are two what are these only go saccharides right and these oligosaccharides which are expressed on the surface of the precursor cells of the red blood cell they are modified they are modified by the help of a special type of chromosome and this is chromosome number 19 and from there a gene expresses a gene expresses on the chromosome number 19 and this special gene which I'm referring to is going to make a special type of enzyme and that enzyme is yes this enzyme is called sinkholes pronounce it rightly fuko's fuko's passphrase right be careful fucose transference transference what is fuko's transferase fuko's is a simple sugar so this enzyme can take simple sugar with sugar fucose and transferred to this oligosaccharide and transfer to this only goes hacker ID so what happens if this enzyme expresses if this enzymes expressive I will call it fucose trance phrase right this enzyme expresses it will attach the which molecule fucose molecules with this chain and this is fuko's what is this fuko's now this oligo saccharide chain with fucose is called h substance what is it called h substance or h antigen is that clear now this expression this mechanism happens in everyone's red blood cells all of you either you it does not matter your blood group A or B or a B or o whatever is your red blood growth you are going to make first h-substance you are going to make your original poetic precursor cells are going to make what H substance right so it means that I can say that here there are H substance now you understand what our H substance we can call it h antigen also is there right now I can lick it like that this is fook H and edge right okay this happens in all of you right during their services so it means all of us red blood cells on the membrane do Express each substance is there right now stop the story here come back to blood group a right our friend who had blood group a in his blood in his synthetic machinery during the rest of choices goes one step further what is that step I said first of all which chromosome was there yes 19 and that night chromosome number 19 was making fucose transferase it was making fucose trois frères so in this person in this red blood cell there is oligosaccharide with fucose well but there is one additional activity here what is the traditional activity we need to go to the chromosome number nine chromosome number nine how many chromosome one chromosome number nine you have in your one arrow blast suppose normally in a cell in a given human cell standard typical human cells how many chromosome number nine you have yes man two one is coming from another is coming from mother both are not coming from father so what happens as you know most chrome chromosomes from one to twenty two are autosomes and x and y are the sex chromosomes now chromosome number nine is autosome autosome one comes from mother another chrome phone comes from father so come here so this young man I said he has blood group a now what he is doing please do is happening in his research site precursor cell chromosome number nine one which came from mother which came from mother and other one came from this is maternal chromosome and other came from father right now these two chromosome had a special locus here at a special locus at the long arm of chromosome number nine right they have a gene they have a gene and this gene when it expresses it makes a special type of transference and that trance phrase is yes hold on I will tell anyone it is not fukuko Strasse phase there is another type of transfer is made here that is called yes anyone can tell me what is the name of that transference okay this is that transference yes this was phrase is an enzyme which can transfer and SC tile get to the mean Gullit Tosa now at chromosome number nine there's a genetic locus work at this specific locus right when this gene is expressing and person with blood group a this is going to make which enzyme yes n acetyl glucosamine transferase activity right so at the top of this this person has already made a CH substance at the top of that it will transfer we can call it n AG a and acetyl glucosamine transferase so what happens here we have added a special top on this this special top this whole molecule now is called a antigen it is called a antigen now you understand what is a antigen a antigen is a antigen is produced by addition of an acetyl glucosamine to the H substance or we can say when each substance is added n acetyl glucosamine by the help of this transferase then each substance is converted into which antigen a antigen right which means all those people who have blood group a like him all those people who have blood group a they initially produce each substance and then and do transfer activity of a special terminal sugar and that is n acetyl glucosamine and then this whole molecule is called a antigens so we can say that all of these where I am putting a a molecule I can enlarge here right and if you look at it what is that this is the Liga saccharide and here was worth it fucose both of them are making each substance and at the top of that what we have added Naga Naga or simply call it and se child the lactose amine collected Ameen this activity is done by a trance phrase and this transfer is because this transfer is is converting each substance this transference is converting each first half into antigen a so we call it plus we can call it transference a a simple name can be okay I'll write it here simple name can be prosperous a is it clear from where the blood group accounts you can go back now let's talk about the blood group B yes so my this friend has blood group B and if he has blood group B we come to this story it means she has B antigens now how is his red blood cells have B antigens on their surface but from where the B antigens come story is somewhat similar we take a precursor red blood cell right as you know you activate chromosome number nine and that will lead to the formation of fuko's prosperous and oligosaccharides right they will have on their surface on the side attachment of focus and of course many of these molecules will be made whole you go second ride with fuko's and this is eight substance after making this then he'll switch chromosomes will be activating maternal or paternal oh yes both can be activated but just a minute this is again the locus now remember this special point let me make it it's a star point this star point on this chromosome chromosome has many many genes and specific genes are specific genes are present at special location and this special location is called genetic locus this is called genetic locus now in this person with blood group a at this genetic locus the gene which was present was responsible to make transferase activity for n acetyl glucosamine but at the same locus at the same position in this person there is a variant of gene not exactly this gene there is a variant of slightly varied genes which makes a different type of transference which makes a different type of transference let's suppose this makes a transference which transfers this transference is transferring not an acetal click-clack to the mean it's not transferring and a still collectors I mean it is transferring only galactose it is transferring here only galactose what is this galactose so whatever h-substance are produced here in this person due to the production of no due to the production of which transfer is collect galactose transferase we are having galactose a tight over here right and once to the h-substance galactose is added when on the edge substance galactose is added this is called B antigen what is called this is B antigen that is why this transference is also called be transference right now let's compare both of these persons come here now what we can say you can come here now we can compare this is blood group a this is blood group B both of them do make each substance both of them on the red blood cells do make such substance and once they have made each substance this person produces a trance phrase a which transfer and its tail blood to the mean to his red blood cells each substance and thus it generates antigen a and that is why his blood group is called blood group a but in this person what is happening that is this person first again each substance is produced but because of the presence of a different transfers here which transfers galactose on the galactose of lactase which we can see it galactose on the top of what is this H substance so this will convert into B antigen so now you clearly understands the difference between that a person with a blood group or with a antigen and person with B flip the blood group with B antigen is that layer please have a seat here I want to make one more story clear before I move further person who has blood group a he has a antigens here now this gene which produces transference a this gene is present on maternal chromosomes maternal chromosomes or paternal chromosomes it may be present on any one of them or may be present on both before you tell me something totally new let me tell you this gene which produces transfer is a it may be present in only one chromosome either it is coming from mother or father or it may be coming from both sides so it means that it is possible that all those people who are having blood group a some of them have are having this gene on both chromosomes in this case they are producing high amount of this one time and they are rapidly Lea converting the aged substance into a antigen is the right now phenotype phenotype is the expression of gene on the producing a trait phenotype of this cell is a but genotype is a a one a from maternal side other from paternal side so one person one person may have blood group a because it's maternal and paternal both chromosomes contain a gene which is producing transfer AC but this is also possible but just remember this later on I will go into further detail in this but okay I will go into further detail if one person has on one chromosome functional gene and other gene is not functional adult side the same locus gene is not functional right I will tell you what is this non-functional gene later again one person both sides functional is producing lot of transference a done but we you may come across one more person in which one chromosome has activity which is producing transfers a other is non-functional gene what will be his blood group still blood group a because even though he will be producing less transferase but still that less transfer phrase will be enough to convert all the h-2a it means genotype genotype can be a a maternal and paternal a or there may be a oh this a from maybe maternal or paternal oh maybe from other partner other parent but you need to remember when there are two a blood hey but even if there is one a still blood group is a it means all those people who have blood group a all those people in this world who have blood group a if you study their genotype genetic material here at this locus some will have both sides same gene we call them their homozygous for a and some will have one side at one locus of chromosome what activates other side there may be inactive non-functional gene then we call it a oh and this is not homozygous this is heterozygous so people who have blood group a if you look at the genotype it may be homozygous or heterozygous a is that clear now we come to this thing we came here now here was transferring a gene and here is transference be gene this was a person who is going to make blood group B what is this gene transfer s B now let's suppose he has transference be here on maternal side as well as he has transference B gene on which side paternal side if both of them are producing transference be heavy amount of transference B is produced which is rapidly converting each substance by addition of galactose into antigen P but it is also possible there from one parent you get if both parents you get what is this may be or it is possible that from one parent you get active gene B or other side at the same locus there is inactive gene so this will be B oh you are under straining so in this case all the people in this world who are having blood group some of them will be B P when genotypically there will be baby because from mother and father both sides they are receiving active genes but some will be Bo we're from one parent they are receiving the active gene that is for transferase B and other side is having inactive gene a non-functional gene am i clear so how many genotypes genotypes are there for blood group a there are two genotype phenotype is a genotypes at a a or a oh people who have blood group B how many genotypes they can have BB or they can have B oh this person will be homozygous and this person will be heterozygous is that clear now we come to person like me my blood loop is a B it means the double action going on right what is that double action first of all the basic activity chromosome number 19 making fucose transferase and these oligosaccharides and this will go saccharides they are having what fuko's h-substance clear after that i have one chromosome from my mother and other chromosome is from my father right paternal chromosome is jino and of course there is a little lipstick - and here is father chromosome you can understand what is it i am little right if on the same locus a chromosome number nine let's suppose this is that locus same locus here there is the gene which is going to make transference a process a that is and from here from maternal okay it doesn't it doesn't matter from which side is coming out from which side B is force paternal chromosome that is making transference be transference B so in my precursor red blood cells one parent chromosome is making transference a and other chromosome parents chromosome making process B so both of them are active so what will happen to my these antigens and some people it will be converted into antigen a and in other persons in sorry and other molecule sorry some H molecules will be converted into antigen a by this action and other H molecule will be converted into antigen B by these actions so my red blood cells will have both kind of molecules antigens as well as B antigens and my blood group will be a B right and how many genotypes I can have only one don't tell me zero genotypes who said this then I have one genotype because it is possible from father a and mother beside or it is possible father is giving B locus D and mother is giving a but in both cases it's a B so here is BB and B 0 B Oh here's a n/a oh here is a B and then a B so there's only one time you understand it so how many underlying genotypes we have learned genotypes for blood group a we have two genotypes for blood group B we have two possible combination for blood group a B we have only one genotype now I want to ask one more thing okay let's go to next person this is blood group O what happens in this person that he's producing h-substance as I told in the beginning of the lecture but the issue is this that at chromosome number nine at the same locus okay I will show it by green color de non-functional gene variant non-functional gene variant it has on both sides non-functional gene variants it means actually it is mutated to be very true now these two are actually in the during the evolution of humans some where it got mutated and due to mutation they do they don't produce active products so they are non-functional or minimally functional so even though these genetic genes are present over there but they cannot produce transference a and they cannot produce transferase B and whatever they're producing is not functional so in such patient can H convert into a and there can it convert into B antigen no so it means there is zero change in them there is ZERO change in H because it is zero so some people started writing this blood group is zero and then other people modified the concept they read zero as oh so they say this blood group is O so what is blood group O if I say come please here if if I say this person is having blood group O what's going on in his or its repetitive process as far as system is concerned what happened there in his system that chromosome 19 was able to attack the fuko's to the oligosaccharide and produce h substance but from maternal and paternal both sides he received the genes which we call it yes what we call this genes which are inactive genes they do not produce any functional transferases so each substance could not be converted into a antigen or B antigen so they stay the H antigen or H substance right is that clear and such people who are having only H sub strands on their red blood cells of course they do not have a or b antigens on the red blood cells such persons group is called oh group please have a seat any question up to this now let me make it some terminology more this is chromosome number nine in all examples but we have seen and at this very special star point or we can say special locus sometimes a gene is there which can make which can make master is a right sometimes this gene which is transferase B and sometimes there is gene which is non functional it means at one locus there can be only one gene you just imagine now listen carefully just imagine here is a this locus is like a cup ice cream ice cream Cup either you put what here chocolate flavor or you put vanilla flavor or you put at ice cream which is tasteless no taste is the right tasteless ice cream so this position gene may be having for transference a or transferase B or non-functional is that right now what is the relationship of these genes with each other what is the relationship of these genes these genes are called alleles of each other that this genes are called alleles of each other you have heard the word a little too many times what are alleles alleles are variants of one gene variants of one gene like variant of ice cream now there can be many flavors of ice cream in the same way one gene may have many variants as long as that gene is present on the same locus same position of the chromosome right for example I have one chromosome okay let me tell you more clearly I don't have here but I will give example of here what do you think I should give example of blonde here and black here example loud you want me to blue eyes and example tell me I will explain the alleles you want about eyes okay suppose there are two chromosomes they determine the color of the eye one chromosome is coming from mother other chromosome is coming from father as I write at a very special location spot at this point at this point these locusts are same on fingers so we'll call them homologous positions and these if this is chromosome number whatever number is this it is the same number of chromosome for example if this is one chromosome this is also one then they are homologous chromosome if it is chromosome number ten this is also chromosome number ten their homologous chromosome I'm just trying to teach you a little basic right on the homologous chromosome at the same positions at the same locus whatever genes are present if they are variant we call them alleles is that right now let's suppose if there is go finger or diagram where you understand better diagram okay let's suppose these are two chromosome and this is a special locus here in here this locus is going to tell the color of the eye it determines what kind of pigment can be produced and what should be the concentration now and these both locus one is coming from mother other is coming from father for example from mother side this is maternal and this is paternal from mother side it becomes brown color and from father side also it becomes brown color so we say mother and father both have given alleles is this person has inherited the alleles from mother and father both side for which color brown color his eyes will turn maybe I will turn brown now another baby here one parent is giving for the brown color brown color other parent is giving the allele for blue color what will be the color of the babyís or one will be brown another will be blue or half will be brown and half will be blue yes what will be the color of ice no no okay then you must know which with gene is dominant blue or brown brown is dominant so what happens if both have brown baby eyes are brown but if one is blue other is brown brown is the dominating brown is the dominating gene so still baby eyes will be brown here genotype will be blue and brown but phenotype will be venom side brown is the right here genotype is brown brown and phenotype is also brown but now we imagine another baby which inherits maternal allele for blue and paternal allele also below now what will be the color of is blue what did we learn here we learn the same that if brown one is brown one allele is brown and other allele is blue then brown will dominate and show its effect and blue is recessive below is a recessive because in the presence of brown it becomes suppressed and it does not show make blue eye is that clear blue colored IMSA is there right now we come back to this so if you really want blue eyes then both of them should be mother and father both should bring which color blue is that right now we learnt this is dominant gene and this is recessive genes a recessive gene now we come over here here at said if there is a allele what is this air lil other may be air may not be a other may be a or may be non-functional or may be non-functional what will be the group of blood a so it means a is dominant or recessive it is dominant in the presence of oh okay we call it Oh in the presence of Oh a dominates so you call it autosomal dominant gene and this Oh will be recessive this is recessive now we come again so that is why people who have blood group a they have both a or they may have one a but because a gene is dominant then Oh will not have in France and still blood group will be a is their right now we come to next example even be now so dominant why because if B is present with B of course B group is there but if B is present with O still blood group will be B so it means B is also dominant in the presence of O which is non functional clear but now come over here one parent give a allele for allele for transfers a other parents give a little for transference B right now both of them are able to express so none of them is a recessive and both of them are dominant both of them are expressing so what we what we can say here this is poor dominance code dominance you know when husband and wife both of them are code dominance they are fighting all the time because both of them want to have their expressions if one partner is recessive other is dominant then system is played very easily right but whole structure of the family will be according to the dominant partner and the system will be just agreeing to everything whatever is happening but if both of them are codominant probable will come but let's come to what is happening here both of them are actually this Oh is recessive in the presence of B oh is also recessive in the presence of a but if so none of them could be oh but when both of them are together like glue I situation if both of them are together then all create is shown blood group will become O so all the babies in this world who are born with blood group O their genotype must be O both sides oh is that right all babies which are born with blood group a B the genotype should be a B but all the babies were born with blood group B their underlying may be BB or Bo and all babies were born with a right they they will have underlying genotype either a a from both parents they are bringing the allele which is a or a oh right and the question up to this clear okay let's have a break thank you

Channel: Dr. Najeeb Lectures

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Keywords: blood, blood group, blood groups, abo, ablo blood, abo blood group, abo blood group system, dr najeeb, dr najeeb lectures, physiology, blood physiology, histology, blood type, blood types, medical lectures, medical education, medical videos, usmle step 1, medical school, medschool, antibody, antigen, blood group a, blood group ab, blood group o, blood tansfusion, medicine, rbc, red blood cell, plasma, antigens, antibodies, ab antigens, anti a antibody, anti b antibody, medical, usmle

Id: wfqnNuYIY78

Length: 47min 11sec (2831 seconds)

Published: Thu Sep 07 2017