13.1 Homeostasis in Humans
1. The internal environment consists of interstitial fluid and blood plasma that constantly bathe the cells.
2. Homeostasis is the process of regulating the physical and chemical factors in the internal environment, so that these factors can be maintained in a dynamic equilibrium and optimum condition.
(a) The physical factors include body temperature, blood pressure and osmotic pressure.
(b) The chemical factors in the blood include partial pressure of oxygen and carbon dioxide, and the salt and sugar levels.