Objective: The term "system" has been used by various States to inform the design of "health systems".In this paper we start from the idea that systems are not natural entities but conceptual models historically developed by researchers to understand, in a certain way, the relationships between component elements of a specific natural, social or cultural reality.Development: The paper seeks to explain how physiological concepts cross-disciplinary and institutional boundaries and become engines that transform various aspects of society and culture.It explores the historical process by which American functionalist social science was based on notions from biochemistry and physiology (especially on the physiological concepts of "regulation" and "homeostasis", and on the biochemical concept of "physical-chemical system") and its influence on public health.Conclusions: This work is part of a trend in alternative histories of Physiology and intends to rethink the problems of representations and practices in health as conflictive social processes.From this perspective of conflict, it seeks to overcome the functionalist system model based on a physiological reductionism of society.