A mathematic model of a cardiovascular system regulated by the baroreflex

A dynamic, nonlinear, lumped parameter model of the cardiovascular system coupled with a baroreflex model is presented. The cardiovascular system in the model consists of the left heart (ventricle) and systemic load and is represented by a fourth order nonlinear time-varying differential equation. The baroreflex is an important internal feedback mechanism in the body whose function is to regulate and stabilize the blood pressure. It plays a major role in the circulatory system by adjusting the systemic vascular resistance (SVR), heart rate (HR), heart contractility and total blood volume based on arterial pressure. The baroreflex model is represented by seven coupled nonlinear differential equations. The response of the combined eleventh order cardiovascular and baroreflex system to single changes in model parameters in preload, afterload, left ventricular contractility, and heart rate is examined. More specifically, by changing certain parameters in the combined model, different levels of human activities can be simulated. The results of our studies show that the model is capable of reproducing coherent human hemodynamic responses which agree with real exercise experimental data reported in the literature