As is well known, physiology is the science of the mechanical, physical, and biochemical functions of living systems. It is a subcategory of biology. In physiology, the scientific method is applied to determine how organisms, organ systems, organs, cells and bio-molecules carry out the chemical or physical function that they have in a living system.
Development of theoretical physiology is associated with the contributions of Alexei Ukhtomsky (1875-1942), Pyotr Anokhin (1898-1974), Pierre Vendryès (1908-1989), and other outstanding physiologists. Along with this, nowadays there is a growing development source which was not available in the past but which can give second wind to theoretical physiology. Indeed, as is noted above, an inherent part of physiology is physics. This interrelation should connect theoretical physiology and theoretical physics. Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics in an attempt to explain natural phenomena. Its central core is mathematical physics (though other conceptual techniques are also used). The goal is to rationalize, explain, and predict physical phenomena. Thus, the role of mathematical-physics models in physiology is expected to be similar. These models should rationalize, explain, and predict phenomena in living systems studied in theoretical physiology.
This issue was realized by physiologists decades ago, for instance, in [1]: "Scientific understanding in physics or physiology is based on models or theories devised to describe what is known. . . Carefully integrated models can be used for prediction. . . This is the systems approach, the basis of theoretical physiology; the models, like those of theoretical physics, should be firmly based on fundamental reproducible observations of a physical or chemical nature, held together with the principles of mathematics, logic, and the conservation of mass and energy. Modern computing power is such that comprehensive models can now be constructed and tested. . . ". Along with this, generalization of the mathematical modeling used for nonliving systems, which physics and engineering usually deal with, to the modeling for living systems should take into account the features that distinguish living systems from the nonliving ones. They