What Is Homeostasis?
Homeostasis is the maintenance of a stable internal environment within an organism, ensuring that conditions remain within narrow preset limits despite changes in the external environment.
Every cell in your body depends on the surrounding fluid being just right — the correct temperature, pH, glucose level, and water balance. If any of these stray too far from normal, enzymes malfunction, proteins denature, and cells can no longer carry out their essential processes.
Homeostasis is what keeps these variables stable. It is not a passive process — it requires continuous monitoring and active correction.
In multicellular organisms, blood plasma and tissue fluid form the internal environment that directly bathes cells. Keeping this fluid composition stable is the central challenge of homeostasis.