[Mathematical model for study the reliability of organism function in extreme conditions of high altitude]. / Matematychni metody doslidzhennia problemy nadiinosti funktsionuvannia orhanizmu za ekstremal'nykh umov vysokohir'ia.

The health of a person and his capacity for work under conditions of high mountains in many respects is determined by the reliability of the function of physiological systems. Mathematical methods of both the reliability theory and mathematical simulation of basic functional systems are proposed to be used for investigating the reliability. It is shown that the most suitable reliability model for living systems is a chain model-a successive connection of links representing separate functional systems of organism. Besides, the weakest links determining the reliability of functioning of the whole organism under the extreme conditions of high mountains even for a healthy person are-respiration, blood circulation, thermoregulation and psychophysiological systems. Quantitative characteristics of the reliability of these systems are determined through the main indicators. The influence of non-sufficient contents of oxygen in respiration mixture, low atmospheric pressure, low temperatures of the environment are simulated by computer models of organism. An analyses of modeling data shows that moderate physical loading improves indicators of organisms adaptively to external conditions of high mountains and promotes the increasing of persons capacity for work and the reliability of his functioning.

[Dynamics of the process of gas transport into the body using a mathematical model]. / Issledovanie dinamiki protsessa perenosa gazov v organizme s pomoshch'iu matematicheskoi modeli

Dynamics of mass-transport of oxygen, carbon dioxide, and inert gases in lungs, blood, and tissues, as well as gas transport through alveolar capillary and erythrocyte membranes at rest and during exercise under normal and increased ambient pressures, were studied on a mathematical model. The model consists of 34 differential and 58 algebraic equations and makes it possible to estimate the dynamics of changes of over 90 parameters. The effect of various factors: duration of the respiratory cycle, tidal volume, airways resistance, the surface of diffusion, the resistance of alveolar-capillary wall, erythrocyte membrane, ventilation-perfusion relations, pulmonary blood shunts, blood supply to the tissues, Haldane and Verigo-Bohr effect, buffer capacity of the blood, and others) on the mass-transport of gases were quantitatively estimated.