A Consideration Of The Hormone Calcitonin And Its Possible Mode Of Action
French physiologist Claude Bernard (1813-1878) was the first investigator to recognize that the composition of the fluids bathing the cells of the multicellular organisms must be controlled. He proposed that the stability of this internal environment, which he termed the milieu organique interieur, gave the body a degree of functional freedom from the variability of the external one, the milieu cosmique ambiant. The internal environment must be both stable and capable of dynamic change in response to fluctuating concentrations of ions. It is the ability of an organism to respond to changes in its environment that, is the concern of modern biology. Response is brought about by the coordinated activities of two major systems: the endocrine system and the autonomic nervous system. The first chapter of this paper is concerned with presenting a brief understanding of the mechanisms of endocrine control both intracellularly and systemically. The discussion will center around the particular endocrine systems that regulate the concentrations of the divalent cation Ca++.