Homeostasis is a very important concept, one of the first that a neophyte should learn when he approaches the study of the human body.
The term homeostasis derives from the fusion of two Greek words, òmoios, "similar" and stasis "position". The father of this neologism was Walter Cannon, who took up the concepts of Claude Bernard, according to which "all the vital mechanisms, however varied, have nothing but a constant aim: that of maintaining the unity of the living conditions of the internal environment'.
The term homeostasis defines the self-regulation capacity of living beings, which is very important for keeping the internal environment constant despite variations in the external environment (concept of dynamic equilibrium).
Let's think for example of the central temperature of our organism, which is kept at values close to 37 ° C despite environmental variations (within certain limits of course). Even the pH of the blood, slightly alkaline (7.4), cannot undergo too wide fluctuations, which when they exceed 0.4 points cause very serious pathologies (acidotic coma and alkalosic tetany).
In Cannon's original concept, homeostasis refers, in particular, to the dynamic maintenance of volume, temperature and acidity of the "internal medium" (blood plasma, interstice and intracellular fluids); this condition is essential for the survival of the whole organism.
Any important alteration of homeostasis leads to disease or even worse to death. In diabetes, for example, there is a loss of glycemic homeostasis, with blood glucose values higher than normal; in hypoglycemic coma the opposite condition is recorded.
a receptor capable of picking up the variations of the internal medium;
a center of integration and control that interprets the signals of the receptors and regulates the responses;
an effector mechanism entrusted with the task of producing the responses (actions) necessary for restoring the optimal conditions typical of homeostasis.
