ABSTRACT
Based on the minimal energy uptake, the proposed mathematical model of blood circulation and external respiration functioning during high-pressure oxygenation or hyperoxia allows solution of the optimization task with restrictions dictated by adequate functioning of the two systems. Optimal levels of oxygen and carbon dioxide pressure in arterial and venous blood, minute blood volume and alveolar ventilation as a function of O2 partial pressure in inspired gas mixture were determined. Calculations are compared with experimentally derived values.
Subject(s)
Blood Circulation/physiology , Hyperbaric Oxygenation , Hyperoxia/physiopathology , Models, Theoretical , Pulmonary Alveoli/physiopathology , Respiration , Blood Gas Analysis , Carbon Dioxide/blood , Humans , Hyperoxia/blood , Oxygen/bloodABSTRACT
Oxygen partial pressure in inspired gaseous mixture has a profound effect on the function of the circulatory, respiratory and erythropoietic systems. A mathematical model is proposed to optimize the function of these systems when breathing air with various PO2. The model is based on the principle of minimum energy expenditure. Erythrocyte count, arterial oxygen tension, cardiac output, and pulmonary ventilation are determined as a function of inspired PO2. The model results are in good agreement with the data for permanent altitude residents.
Subject(s)
Blood Circulation/physiology , Erythropoiesis/physiology , Models, Theoretical , Respiration , Humans , Oxygen , Partial PressureABSTRACT
Proposed is a mathematical model of the functional state of the hemopoietic and erythropoietic systems in microgravity or long-term bed rest built on the principle of the minimal energy demand. Parameters of hematocrit, blood volume and minute blood volume in microgravity or long-term bed rest were determined. Results of model testing are in good agreement with the data about functioning of these systems in cosmonauts.
Subject(s)
Erythropoiesis/physiology , Models, Theoretical , Blood Circulation/physiology , Hematocrit , Humans , Oxygen/bloodABSTRACT
Based on the principle of minimum power, a mathematical model of the structural organization of the microcirculatory system is presented. The optimization model minimizes the power expenditure of the heart, bone marrow and the power expenditure in blood carrying. The structure of the microcirculatory bed in the heart, lung and skeletal muscles is considered. The optimal number of capillaries arising from one terminal arteriole is determined depending on oxygen transport parameters. Arterial blood volume as a function of body weight is also determined. Theoretical results are compared with experimental data for man.
Subject(s)
Blood Volume/physiology , Microcirculation/anatomy & histology , Models, Cardiovascular , Arterioles/anatomy & histology , Body Weight/physiology , Coronary Vessels/anatomy & histology , Humans , Lung/blood supply , Mathematics , Muscles/blood supplyABSTRACT
Based on the principle of minimum power, a mathematical model of the functional state of the pulmonary circulatory and respiratory systems is presented. The optimization model minimizes the power expended by the right heart and respiratory muscles. The pulmonary diffusing capacity control mechanism is considered. Mean pulmonary arterial blood pressure and ventilation are determined depending on oxygen transport parameters for man under normal and chronic pathological conditions. Theoretical results are compared with clinical data.
Subject(s)
Blood Pressure , Models, Biological , Pulmonary Artery , Adult , Capillaries/physiology , Humans , Lung Diseases/physiopathology , Male , Mathematics , Pulmonary Diffusing CapacityABSTRACT
Based on the principle of minimum power, a mathematical model of the functional state of the circulatory system is presented. The optimization model minimizes the power expenditure of the heart, bone marrow and the power expended in carrying blood. Mean arterial blood pressure is determined depending on oxygen transport parameters and locomotor activity. Theoretical results are compared with experimental data for man.
Subject(s)
Blood Circulation/physiology , Blood Pressure/physiology , Cardiovascular Physiological Phenomena , Hematocrit , Humans , Locomotion/physiology , Mathematics , Models, BiologicalSubject(s)
Microcirculation/physiology , Animals , Capillaries/physiology , Humans , Mathematics , Models, Biological , Muscles/blood supplyABSTRACT
Based on the principle of minimum power, a mathematical model of the exercise functional state of the oxygen transport system is presented. Aerobic and anaerobic muscular efficiencies are considered. The energetically optimal arteriovenous oxygen content difference, cardiac output and ventilation during exercise in man are determined depending on mechanical power. Theoretical results are compared with experimental data.
Subject(s)
Models, Biological , Oxygen Consumption/physiology , Physical Exertion/physiology , Animals , Cardiac Output , Humans , Mathematics , Muscles/physiology , RespirationSubject(s)
Blood Circulation , Hematopoiesis , Models, Biological , Motor Activity , Blood Volume , Hematocrit , Humans , MathematicsABSTRACT
Automatic control systems for the artificial heart (AH) and ventricular assist device were developed using selected criteria of effectiveness, a mathematical model of regulation, and noninvasive measures of the hemodynamic parameters. The Sinus IS2 system was developed for control of the AH; its main component is a high-speed servomechanism that provides for the generation of pneumatic pulses. The servomechanism is controlled by automatic regulation with pressure feedback. Mean aortic pressure was used as the primary regulated hemodynamic parameter. The systems were tested using both a physical model and a physiologic experiment. Contractile insufficiency of the left ventricle was simulated in testing the control system for circulatory assistance. The studies demonstrate that automatic control systems function effectively by providing normal blood circulation in both the resting state and in certain transient processes occurring in a real, dynamic circulatory system.
