Homeostatisk

Homeostatisk, or homeostatic, refers to the property of maintaining a relatively stable internal environment in a living organism or in a system, despite changes in the external environment. The concept of homeostasis was developed in physiology by Claude Bernard and later popularized by Walter Cannon. It describes regulatory mechanisms that keep critical variables within narrow limits to support cellular function and organismal health.

Functional regulation relies on three types of components: sensors that detect deviations, control centers that compare against a set point, and effectors that bring about corrective responses. Most homeostatic regulation uses negative feedback, which counteracts the initial perturbation. In some cases, anticipatory adjustments (feedforward) or allostatic mechanisms adapt to longer-term demands.

Common examples include thermoregulation, where body temperature is kept near 37 degrees Celsius by vasomotor changes, sweating, and shivering; glucose homeostasis, maintained by insulin and glucagon; osmoregulation and fluid balance governed by the kidneys; and acid-base balance maintained by respiration and renal excretion. Calcium, iron, and other minerals are also tightly controlled.

Disruptions to homeostatic processes can lead to disease. Fever, hypothermia, diabetes mellitus, dehydration, electrolyte imbalances, and acid-base disorders illustrate how failing regulation affects health. Treatment often aims to restore or support the body's regulatory capacity rather than simply addressing a single symptom.

In broader contexts, the term homeostat is also used in cybernetics and engineering to describe an apparatus or model that demonstrates self-regulation through feedback. Such ideas influenced early artificial systems and modern control theory, where maintaining stability in the face of perturbations remains a central goal.