Overview

This chapter is dedicated to studying and simulating blood pressures and flows in the circulatory system.We have already seen how transport phenomena are central to the operation of biological systems. In the previous chapter we saw how the pumping of the heart is responsible for driving blood flow to transport solutes throughout the body. Here we focus on the mechanics of the heart and circulatory system themselves.

Pumping of the heart and flow of blood throughout the circulatory system represent a critical life-support system in man. Malfunction of the heart and/or the circulatory system is associated with a great number of diseases and pathophysiological conditions. For example, hypertension – chronic systemic high blood pressure – puts stress on the heart that can ultimately lead to its failure. Here we will see that the functioning and malfunctioning of the circulatory system are best understood in terms of mathematical models that capture the key mechanistic underpinnings of its anatomy and physiology.

Our modeling and analysis in this chapter will rely on lumped parameter circuit models, analogous to electrical circuits made up of resistors, capacitors, and inductors. Readers not familiar with simple circuit analysis may choose to review Section 9.7 of the Appendices, which provides a short background on the subject, before undertaking this chapter.

We will begin our study of the circulatory system with an analysis of the main pump responsible for moving blood through the circuit described in Section 3.2 of the previous chapter.