Centaurine innards

[desperance]

Okay, look. I'm quite happy with one digestive system that has two separate stomachs en route, there are instances of that and stranger things; but are we to suppose that a centaur has two sets of ribs, human and horse, and - therefore? - two sets of lungs within 'em? Skeletally, see, I think they must; and you'd need horsey lungs, I'd guess, to power a horsey body. Which would imply two hearts also, unless the human half just didn't bother with a heart, because the horsey one was good enough for all; I'm okay with that either way, I just have trouble with the lungs thing. Only one intake-pipe, after all: does the poor girl have to breathe for two, great vasty draughts of air...? Or if she just has one set of horsey lungs, what's in the human chest cavity...?