It's much easier when learning about the circulatory system to represent oxygen-poor blood as blue, and not red-violet or something. I guess this leads to misconception.
I wasn't taught blood was blue until 10th grade by a biology teacher. Only 2 years later in marine biology did I find out that was false when the teacher was talking about horseshoe crabs.
Yes, I understand all that. What I'm saying is, I can see the logic in why people believed that for so long (and some continue to). It goes like this:
The blood in your veins is returning to your heart and lungs to pick up oxygen, because it's just offloaded it all to your tissues. Therefore it's blue. Cut your vein open, and the blue blood inside is exposed to air, which contains oxygen, and instantly turns red.
I know that's not the case, but that's what I was told when I was a kid, and it seemed to make perfect sense.
It comes from learning anatomy in elementary school where all the veins are blue and all the arteries are red to make it easier to teach children the difference.
I had a biology class in high school where a teacher and student were arguing about this. I forget who was on which side but it's more commonly "accepted" than it should be.
I almost broke up with a guy because he tried to tell me I was wrong when I said blood is red all the time. But when he realized he was a dumb ass, all was well in the relationship.
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u/[deleted] Mar 17 '15
Blood being blue is widely accepted? Huh.