Hmm, the human body is such a complex instrument (as are almost all life-forms, and we are naturally largely similar to the others) that generations of scientists and doctors have specialized in attempting to understand and deal with even so-called minor components of it. Yes somehow a vastly simplified view of any aspect is going to give on insight into all the complexities, with no further effort needed? I don't buy it.
And yet -- it is precisely so, although effort is still required. Systems which are too chaotic to be predicted nevertheless have demonstrable, if devilishly complex rhythms and patterns that obey VERY simple iterative laws. The intricate complexity of resulting behavior does not imply complexity of the cause or principle that produces it.
The following bifurcation diagram can be generated by the simple linear increase of the rate of flow to a dripping faucet, each point representing the time between drops (y axis) at the rate of flow (x axis).
So do not disregard the reality of simple causes underlying complex events.