Bridging physiology and psychology: a new framework for teaching homeostasis.

Classical physiology teaches homeostasis as a set of reactive feedback loops that stabilize the body's internal environment. Yet emerging science shows that human regulation is not merely reactive but profoundly shaped by cognition, emotion, belief, and predictive brain processes. We propose an updated definition of homeostasis that positions the brain as an anticipatory, meaning-making regulator integrating physiological, emotional, and environmental demands. This predictive regulation also unfolds across time through circadian organization, in which central neural systems coordinate daily rhythms in endocrine, immune, metabolic, and cognitive activity to prepare the organism for anticipated environmental and behavioral demands. By reframing homeostasis as a psychophysiological process, this work highlights the need for medical education to move beyond reductionist feedback-loop models and adopt a more integrated, clinically relevant understanding of human regulation. Within this framework, cognitive expectations, emotional appraisal, and circadian timing together shape how the brain allocates physiological resources in anticipation of daily challenges. This framework offers a rigorous yet human-centered lens for interpreting health, disease, and the therapeutic power of the clinical encounter.