What’s the difference between blood in people that means we have different “types” and why are some incompatible?
In: Biology
Your immune system is constantly patrolling your body, like a police force, looking for things that don’t belong. To do this they have a long list of “markers”, things that “look suspicious”. If your immune system finds something that fits a marker on the list, it attacks the thing. THESE LISTS CAN BE DIFFERENT FOR DIFFERENT PEOPLE.
Now, blood cells often have some of the markers that appear on the lists… your own blood cells shouldn’t appear on your own immune system’s list, of course. Then your immune system would attack them. But your blood cells might have some markers that appear on other people’s lists, so if you donated blood to them, their immune system would attack the blood they got from you… and that would be very bad for them.
To keep track of these markers and lists, blood types are used. There are three markers that matter here: A, B, and rhesus (+). If your blood type is A+, for instance, your blood has the A and rhesus markers, but not the B marker. That means your immune system will *not* attack blood with the A and/or rhesus markers, but it *will* attack blood with the B marker. Which means you could receive blood from anyone who does not have a B in their blood type, and you could give blood to anyone with A and + in their blood type (so A+ and AB+ only).
Hope this wasn’t too complicated!
Latest Answers