homeostasis and the body capacity to present a characteristic and constant physical-chemical situation, within certain limits, even in the face of changes imposed by the environment.
To keep the conditions of life constant, the organism mobilizes the most diverse systems, such as the central nervous system, the endocrine, the excretory, the circulatory, the respiratory, etc.
In 1859 the French physiologist Claude Bernard said that all vital mechanisms, however as varied as they may be, they have no other objective than to maintain the stability of environmental conditions. internal.
In 1929, W. B. Cannon called this stability the homeostasis (from the Greek homoios -"the same" and stasis -"stop"). He was not referring to a static situation, but to something that varies within precise and adjusted limits. These limits of variation and regulatory mechanisms constitute a good part of the study of Physiology.
Oxygen Homeostasis for Cells
At high altitudes (Andes, Alps, Pyrenees, Himalayas), the oxygen in the atmospheric air is thinner. The respiratory activity of these people in these places becomes insufficient within the normal rhythm. To compensate for this difficulty, the organism makes use of a homeostatic means: rhythm intensification respiratory and then, slowly, increased production of red blood cells, which are soon released into the circulation blood. With a higher rate of red blood cells, the individual is able to efficiently retain in the lungs the little O² that air offers.
Homeostasis of Cell Metabolism
The chemical composition of the internal environment must not change. Therefore, neoformed products that appear at the end of cellular metabolism (CO², urea, ammonia, uric acid, urates, creatinine, etc.) must be promptly discarded. This is done by the lungs (CO2), by the sweat and sebaceous glands, but mainly by the kidneys.
