Why Do We Have Blood Types?

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Published 2020-02-06
A, B, AB, O: What exactly do the different blood types mean and how are they inherited? When it comes to understanding blood types, Patrick’s got you covered.
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Being able to access the right type of blood in a medical emergency can be a matter of life or death. But what even is a blood type, and why are they so important?

We didn’t have a system of categorizing blood types until the early 1900s when Austrian doctor Karl Landsteiner came around and developed the organizational system—the well-known ABO blood groups you’ve probably heard of.

Dr Landsteiner traced transfusion complications back to two things: antigens and antibodies.

Antibodies are proteins produced by the immune system that can recognize, investigate, and if needed, destroy an antigen, which is anything that triggers an immune response.

Oftentimes, antigens are viral or bacterial invaders that can cause sickness or infections. Usually your immune system will recognize them and label them as something to attack with antibodies and get rid of in the future.

But other times these antigens are produced by our own bodies, called self-antigens, which our immune system will leave alone.

The entire ABO blood system is built upon these sugar-based self-antigens and corresponding antibodies, and the type of blood you have tells you which kind of antigens and antibodies we’re talking about.

Type A blood means you have A antigens on the outside of the red blood cells and B antibodies in the plasma. Type B blood reverses this, B antigens on the outside of the red blood cell with A antibodies floating around in plasma.

People with AB blood have both A and B antigens, but no antibodies in their plasma while those with type O blood have absolutely no antigens, but have both A and B antibodies.

Then we have that positive or negative symbol that comes after your ABO blood type. That symbol is based on something called the Rhesus Blood Group System, which was named after a monkey species.

Rhesus blood grouping is similar to the ABO system because it too has to do with the presence or absence of an antigen on the outside of the red blood cell — in this case the protein-based Rh antigen.

This is also important when it comes to blood transfusions as a body with Rh negative blood will reject Rh positive blood.

For the most part, everyone in the world has one of these blood types, but why is our blood like this?

Find out the answer and more in this Human.

#bloodtypes #humanbody #health #seeker #human #biology

Read More:

Why do people have different blood types?
www.scientificamerican.com/article/why-do-people-h…
“For some blood types, evolution and environmental selective pressures are clearly important for their persistence. For example, the Duffy blood type includes a receptor that allows certain types of malarial parasites to enter the red cell.”

Facts About Blood and Blood Types
www.redcrossblood.org/donate-blood/blood-types.htm…
“Blood types are determined by the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body. Since some antigens can trigger a patient's immune system to attack the transfused blood, safe blood transfusions depend on careful blood typing and cross-matching.”

What Happens When You Get The Wrong Blood Type?
io9.gizmodo.com/what-happens-when-you-get-the-wron…
“Being transfused with the wrong type of blood is incredibly rare, but it has occasionally happened. What does it feel like to have the wrong type of blood coursing through your veins? It feels like being doomed. Literally.”

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All Comments (21)
  • @xtieburn
    Interesting thing I like to keep in mind is that these blood types as commonly shown are horribly simplified. There are actually dozens of antigens with ABO representing the most important, even the ABO system is a bit more complicated with sub categories of A types etc, but the Rhesus system is on another level containing dozens of independent antigens. The + or - you see is short hand for the status of Rh D in particular. and there is a whole lot more: Hh, K, MNS, etc. The effects of mismatches can vary a great deal depending on the antigen and population E.g. H deficiency is particularly prevalent in India, and potentially lethal if ignored. This is a very important part of why its so tricky to modify or produce blood ourselves. Also, you can test a great deal about why we have blood types. E.g. you have things like Malaria which gets a hold on A type but not so easily on O type. Given the scale of death caused by malaria, even a small shift in its ability to infect someone would be a major evolutionary pressure, and with the right knowledge about this that evolutionary pressure could be quantified. (Thats only one of a number of other ailments tied to blood type.)
  • @DogsBAwesome
    So the blood donation service will stop nagging me about donating my sweet O neg blood. Even though I book the next appointment for as soon as I'm allowed to donate.
  • @uhohhotdog
    My blood is perfect. You could even give it an A+
  • @theOrionsarms
    Nothing about RH incompatibility between mothers and fetuses?maybe would be a entire episode only about that.
  • @omararreola5449
    I'm so happy how science is advancing and how our understanding is getting even more deep
  • @ikannunaplays
    People always ask why I'm always happy at work, I tell them it's in my blood to just B+
  • @sirraulo9002
    Aww, the Punnet Square. Memories pours in again. So nostalgic.
  • @mediocreclementine7649
    There are so so many more blood type systems to explore beyond ABO. Immunohematology is a field that is grossly misunderstood even within medicine. Blood bank guy here on youtube has some awesome videos on it!
  • @SwedishCowboy420
    Very interesting and informative, thank you for providing historical background!
  • @bloodaid
    I took a blood test and got A+ My parents are so proud of me.
  • @johncaiwa
    Another video with something cool promised in the future that will be forgotten forever in a year.
  • @ShannonMcDowell71
    I was surprised to see a different presenter but Mr. Kelly did a super job; I had forgotten a lot of my "blood knowledge," but he explained it clearly in this video, and I appreciate the overall topic of converting different blood types to universal Type O. Great work! :-D
  • @Lycan3303
    Where my O- brothers and sisters at .. <3
  • @apren9569
    And thus, the mutants were created .