hi everybody dr mike here from dr matt and dr mike's medical youtube channel today we are taking a look at blood types so for hundreds of years we've been performing blood transfusions but we had no idea why some people would survive and some people wouldn't until about 120 years ago we discovered these little flags called antigens that sit on the surface of our red blood cells our erythrocytes and these little flags or antigens give us our blood type whether our blood type is a b a b or o now there's actually many different blood types but the blood typing is the most immunogenic that means it can elicit a very strong immune response and therefore it's the reason why if you get a blood transfusion and it's not compatible with your blood type it can be a very bad thing so let's take a look the different blood types you can have include a b a b and o and again what this is referring to is if i were to take a red blood cell those that are blood type a they have a flag on the surface that's waving saying i'm blood type a this is what we call an antigen and in actual fact this antigen is a sugar and this sugar just says i'm a all right that's blood type a when we look at b and have a look at the flag that b is waving the flag that b is waving is going to be pretty easy it says i'm blood type b and then we look at a b well what's this flag going to be waving well there's going to be two flags right there's going to be a flag that's waving saying i'm blood type a and there's going to be another flag waving saying i'm blood type b therefore together this is the a b blood type and then finally when we look at blood type o there are no flags so blood type o no flags so think about this i like to think about it in regards to different types of villages think back medieval when you've got a castle and you've got a community in a town and that town has a flag that represents who they are right so we've got a has the a flag now think about it all towns or kingdoms have an army now the army that town a is going to have that army isn't going to be trained to attack a it's going to be trained to attack every other flag that it is not now have a look what other flags are available simply just the b flag so that means the army that the a has is going to be against b so it's called anti b and they're actually antibodies so they're anti b antibodies that makes sense so this arm is trained to attack b now what about b well it's waving the b flag it's not going to train an army to attack itself it's going to train an army to attack a so it has anti-a antibodies floating through the blood so that means this person who has blood type a will have anti-b antibodies this person whose blood type b has anti-a antibodies let's think about this what about this one well they're not going to train an army to attack a because it's waving that flag it's not going to train an army to attack a b because it's waving that flag as well so they don't have antibodies against a or b there's no army now let's take a look at the last one oh well it's going to train an army to attack a so it has anti-a antibodies and it's going to have anti-b antibodies so if your blood type o you're going to have antibodies against both a and b now this allows us to know who can donate blood to who right so think about it if you are blood type a you are waving the a flag but you have anti-b antibodies who can you receive blood from you can only receive blood from those that don't have the b flag so you can't receive b blood if you're blood type a you can't receive a b blood now you may be thinking but there's the a flag yes but it's also carrying the b flag right so these b antibodies will attack it what about o well there's no flags so o can be donated to a so what type of blood can a receive a can only receive let's pop it down other a blood or o blood what about b well b is the same in the sense that it has anti-a antibodies so b cannot receive a blood b cannot receive a b blood b can receive b blood so it can receive itself that makes sense and it can receive o blood because there's no flag on the o what about a b well there's no antibodies so a b can receive blood from anyone so a b can receive a blood it can receive b blood it can receive a b blood it can receive o blood that is what we call the universal acceptor universal acceptor so if somebody is type a b it can receive all blood now let's take a look at blood type o well can o receive a blood no because there's a antibodies can't receive b blood can't receive a b blood o can only receive o blood but let's take a look at this let's have a look all of them can receive o can receive o can receive o can receive o so o is actually known as the universal what what do you think it's going to be called the universal donor blood if you are blood type o you are the universal donor and this is a nice run through of the blood types but there's another bit of complexity to add to this you may be thinking yeah but you're not just a or b or a b you are a positive or a negative or a b positive or a b negative where's this come from so this is another flag called the rhesus factor and this rhesus factor is called that because it was first discovered in rhesus monkeys the flag that they wave is actually a d flag a d flag so let's give this as an example if somebody is a positive it means they have the a flag but also the d flag which is the racist factor flag so as you can see there's another level of complexity here so if somebody's b negative it means they have the b flag but no d flag so they're going to make more antibodies if you're b negative and you don't have the d flag you're going to create antibodies against d so people who are b negative are going to create d antibodies as well so that means if you have the negative blood type you cannot receive anything with the d flag that means you cannot receive positive blood of any kind so b negative can only receive b negative blood and o negative blood it cannot receive b positive blood or even o positive blood because they're going to have that flag and it's going to create antibodies against it so this is a quick run through of the blood types