Understanding blood pressure regulation through modeling Adam Mahdi, Department of 
Mathematics, NC State University

ABSTRACT: Understanding the cardiovascular control system is crucial for gaining 
more insight into the physiology not only for the healthy individual, but also to 
detect pathologies. The main role of the cardiovascular system is to maintain 
adequate oxygenation of all tissues. This is achieved by maintaining blood flow and 
pressure at a fairly constant level. To accomplish the transport, a number of 
control mechanisms are imposed regulating vascular resistance, compliance and 
frequency. An important contributor to the cardiovascular control is the baroreflex 
(or baroreceptor reflex), which uses specialized neurons, called baroreceptors, that 
are activated using mechano-sensitive sensors located in the aortic arch and carotid 
sinuses. These neurons are stimulated by changes in blood pressure and contribute to 
short-term regulation of vascular efferents including: heart rate, cardiac 
contractility, and vascular tone. Baroreceptor dynamics have been studied since 
1950s. Unfortunately most models are of little or no biological motivation. In this 
presentation, we will discuss various mathematical techniques and approaches used in 
the past to describe baroreceptors. Finally, we propose a new, biologically 
motivated model, which reflects all known static and dynamic properties of the 
baroreceptors including: saturation, threshold, PED (post-excitatory depression), 
adaptation and rectification.

This work is a part of the bigger project called "The Virtual Physiological Rat 
Project" (http://virtualrat.org/), with objective to build and simulate the 
cardiovascular functions of the rat and build a validated computer models across rat 
strains. The ultimate goal of using mathematical and computer models is to predict 
the physiological characteristics of not yet realized combinations, derive those 
combinations in the lab, and then test the predictions.