Somatic tissues degeneration
The variable metabolic activity of somatic cells perpetually produces the physiological variation of blood flow volume into the systemic venous circulation, which becomes an intrinsic stimulating factor for the functional activity of systemic venous system and atrium and right ventricle. Hence, the carbon dioxide resulting from the biochemical processes of the cellular metabolism, produces the variation of blood volume pressure into the systemic venous circulation (due to PCO2 variation), and reaching the right atrium and ventricle, excites the sympathetic nerve fibers of the right side of the heart, and its specialized nerve center found in the central nervous system involved in the physiological stimulation of the right side of the heart. Also, the amount of oxygen carried from the lungs (which is conditioned and directly proportional to the variation of venous CO2 gradient value from the systemic venous circulation), on reaching the left atrium and ventricle, excites the sympathetic nerve fibers of the left side of the heart and its specialized nerve center from the central nervous system involved in the stimulation of the left side of the heart. In the pathogenesis of cancer there is only one causal factor. This etiologic factor for all forms of cancer is the same (critical decrease in the intensity of cellular metabolic activity), and it is only the conditions for the occurrence of neoplasia that differ. The intensity of cellular metabolic processes is the mechanism that determines the normal cell differentiation and proliferation from the multipotent stem cell to the completely differentiated mature cell also it maintains the cellular energy homeostasis.