Concept of internal environment ('1870) By Claude Bernard (1813-1878) milieu interne [mi:ljo:into:n]French Concept of homeostasis ('1920) By W.B.Cannon (1871-1945) Importance of maintaining the homeostasis Enough nutritional substances O2 Low level of metabolic products CO2 Water,electrolyte,acid-base balance Temperature,osmotic pressure,etc. Homeostasis is a dynamic equilibrium Regulation of homeostasis Involve all systems,especially the lung kidney• Concept of internal environment (’1870) By Claude Bernard (1813-1878) milieu interne [`mi:lj: `int:n] [French] • Concept of homeostasis (’1920) By W. B. Cannon (1871-1945) • Importance of maintaining the homeostasis * Enough nutritional substances & O2 * Low level of metabolic products & CO2 * Water, electrolyte, acid-base balance * Temperature, osmotic pressure, etc. • Homeostasis is a dynamic equilibrium • Regulation of homeostasis * Involve all systems, especially the lung & kidney