Comment on Would having two hearts be better or worse for the human body?

• Onomatopoeia@lemmy.cafe ⁨3⁩ ⁨weeks⁩ ago

  We already have synch issues with a single heart (things like arrythmias). I’m not sure two hearts in a mammal would even work, given the increase in distance for signaling - seems a lot of opportunity for error.

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• Bbbbbbbbbbb@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

  The heart is a really simple contraption. The heart is broken down into 2 halves, and 2 more halves after that, for a total of 4 parts.

  Focusing on one half, what most people would recognize as “the heart” and what it does. Blood enters the heart into a mini pump, that pump pushes blood into a second pump, making it a little extra full, so when that pump decides to squeeze, you get extra force leaving it to send blood to the rest of the body and back to the other half of the heart later.

  Imagine filling a water balloon with half way some water and squeezing it out. It doesnt have as much “umph” as if you filled that same water balloon nearly to its popping point and squeezing.

  The other half of the heart is the exact same, just weaker as it only sends blood a short distance to your lungs and back to the big half of the heart. Thats it, thats all the heart does. 2 pumps that load up the other 2 pumps with blood to be shot out to the rest of the body.

  Sometimes things go wrong, youve very likely felt a small heart spasm before, but the heart is a mostly self correcting, fully autonomous system. I cannot see why adding in a 2nd heart would be a detriment, just makes blood go round and round more often.

  I spent a few years studying as an EMT and Medical Assistant and I think I loved the circulatory system the most. However, Im no doctor and I simplified the heart a bit because I dont think needing to understand everything adds to the theoretical discussion of 2 hearts

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  • FuglyDuck@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    My concern would be complexity.

    More points to fail, and I’m not sure that it reduces single-points of failure much.

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    • Bbbbbbbbbbb@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      I understand the concern, but I see it as more redundancy, like kidneys. If 1 heart gives out, you have a spare, and considering that we only have 1 that can do its job for 100+ years i dont see complexity as being an issue.

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      • FuglyDuck@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

        The problem comes in, what happens when a heart fails? depending on the failure mode, it may represent a total blockage, in which case you’re toast. You might be able to survive with one heart if you had two, but if you add a second heart, then your other heart will likely be less developed unable to perform at whatever peak performance you had before.

        If your method of redundancy adds more single points of failures. Also, the addition of a second heart poses the problem of keeping them coordinated; with all sorts of problems coming up if they get out of sync. adding redundancy will always add complexity, especially as you work to remove single points of failure and try not to add extra. In some systems, it’s just unwise to add redundency because the complexity means it’s more likely to fail.

        Famously, Charles Lindbergh, for example, opted for a single reliable engine over two engines. It kinda flew in the face at the time. But then he was the first to go from NY to Paris in a non stop flight, in the Spirit of St Louis. Similarly, we can expect, if there was in fact some significant advantage, that then, everybody would be doing it. Or, at least, lots.

        Keep in mind, cephalopods have 3 hearts- 2 are single chamgered things that boost blood over gills, and the 3rd provides bloodflow to the rest of the body. Hagfish have one chambered heart and several boster things that aren’t really much of a heart. Earthworms aren’t possessed of true hearts (they lack chambers and valves,) cochroaches and leaches also don’t have true hearts.

        But where we see 4 chambered hearts (birds, mammals, and crocodillian reptiles,) they all only have 1. That should tell you something.

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