How does blood reach literally every cell in the body? There can’t be capillaries between every single cell when capillaries are also made of cells…. can there?

Question

How does this work?

In: 4868

Answer 1

Nah you’re right there aren’t. It’d probably be possible for a organism to engineer some blood vessels made out of cells without nuclei like that one fly that’s smaller then most amoeba and transport oxygen through blood plasma but that’s unnecessary for the same reason why insects can get away with having a full-body lung instead of blood; oxygen diffuses between cells so blood vessels only need to reach *groups* of cells rather then each and every cell individually.

This is also why acupuncture needles don’t normally make you bleed; they’re thin enough to slip between individual blood vessels. It’s just bad luck that one in every five or so hit a blood vessel head-on and make you bleed. It’s also why mosquitos need to be able to detect heat to find blood vessels; if they didn’t then they’d miss four times out of five.