Do people really think the collective functioning of organs that have evolved to cohabitate in a given lump are not subject to constraints so that the lump does

Do people really think the collective functioning of organs that have evolved to cohabitate in a given lump are not subject to constraints so that the lump doesn't all apart? The fact that each subsystem evolved in that environment to get cues from common signals does not mean there is a thing that is aware of the fact that it has communication lines to, say, kidneys, and lungs etc. Given that every single thing is subject to constraints, the things that evolved to work together must be, by necessity, relying on a signaling mechanism so one part does not fall apart trying to fulfill the demands of other parts. Otherwise, the thing we are looking at, in this context, brain in a body, could not have existed in this arrangement.