Human Homeostasis - History of Discovery

History of Discovery

The conceptual origins of homeostasis reach back to Greek concepts such as balance, harmony, equilibrium, and steady-state; all believed to be fundamental attributes of life and health. The Greek philosopher Heraclitus (540--480 BC) was the first to hypothesize that a static, unchanged state was not the natural human condition, and the ability to undergo constant change was intrinsic to all things. Thereafter, the philosopher Empedocles (495-435 BC) postulated the corollary that all matter consisted of elements and qualities that were in dynamic opposition or alliance to one another, and that balance or harmony was a necessary condition for the survival of living organisms. Following these hypotheses, Hippocrates (460-375 BC) compared health to the harmonious balance of the elements, and illness and disease to the systematic disharmony of these elements.

Nearly 150 years ago, Claude Bernard published his seminal work, stating that the maintenance of the internal environment, the inner environment, surrounding the body's cells, was essential for the life of the organism. In 1929, Walter B. Cannon published an extrapolation from Bernard's 1865 work naming his theory "homeostasis". Cannon postulated that homeostasis was a process of synchronized adjustments in the internal environment resulting in the maintenance of specific physiological variables within defined parameters; and that these precise parameters included blood pressure, temperature, pH, and others; all with clearly defined "normal" ranges or steady-states. Cannon further posited that threats to homeostasis might originate from the external environment (e.g., tempurature extremes, traumatic injury) or the internal environment (e.g., pain, infection), and could be physical or psychological, as in emotional distress. Cannon's work outlined that maintenance of this internal physical and psychological balance, homeostasis, demands an internal network of communication, with sensors capable of identifying deviations from the acceptable ranges and effectors to return those deviations back within acceptable limits. Cannon identified these negative feedback systems and emphasized that, regardless of the nature of the danger to the maintenance of homeostasis, the response he mapped within the body would be the same.