Chapter 17
Heart Beat
I have to remind myself to breathe – almost to remind my heart
to beat!
(Emily Bronte ¨, Wuthering Heights)
17.1 Basic Heart Beat Model
In Chap. 4 we have mentioned the fact that organs, or entire organisms, may be
viewed as having evolved to a critical state in which they are seemingly close to
chaotic behavior. Yet, at that stage of their evolution, they may have optimized their
behavior with regard to a specific task. The heart is such an organ, and we model it
in a simplified form in this chapter.
The behavior of the four-chambered human heart follows a series of closely
interrelated flow processes. Deoxygenated blood from the venous system is collected
into the vena cava and then delivered into the right atrium. Blood then is pumped into
the right ventricle past the bicuspid valve. Blood is pumped to the lungs via the
pulmonary arteries where it becomes oxygenated. Blood then is delivered into the
left atrium via the pulmonary vein. From there the blood is pumped into the left
ventricle. The oxygenated blood is then pumped to the body’s arterial system through
the aorta. This pumping rate is controlled by the heart’s pacemaker. Special cells in
both atrial chambers have the ability to send electrical impulses that cause the atria to
contract. The same impulse is also carried to the A-V node which causes ventricular
contraction. The result is first an atrial contraction then, after a few millisecond delay,
the ventricular contraction. A very basic rendition of the heart is laid out in Fig. 17.1.
Our model of the four-chambered heart (Fig. 17.2) is constructed to respond to
changes in blood demand and to disease. A volume of blood is pumped through
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_17,
© Springer International Publishing Switzerland 2014
141
Heart Beat
I have to remind myself to breathe – almost to remind my heart
to beat!
(Emily Bronte ¨, Wuthering Heights)
17.1 Basic Heart Beat Model
In Chap. 4 we have mentioned the fact that organs, or entire organisms, may be
viewed as having evolved to a critical state in which they are seemingly close to
chaotic behavior. Yet, at that stage of their evolution, they may have optimized their
behavior with regard to a specific task. The heart is such an organ, and we model it
in a simplified form in this chapter.
The behavior of the four-chambered human heart follows a series of closely
interrelated flow processes. Deoxygenated blood from the venous system is collected
into the vena cava and then delivered into the right atrium. Blood then is pumped into
the right ventricle past the bicuspid valve. Blood is pumped to the lungs via the
pulmonary arteries where it becomes oxygenated. Blood then is delivered into the
left atrium via the pulmonary vein. From there the blood is pumped into the left
ventricle. The oxygenated blood is then pumped to the body’s arterial system through
the aorta. This pumping rate is controlled by the heart’s pacemaker. Special cells in
both atrial chambers have the ability to send electrical impulses that cause the atria to
contract. The same impulse is also carried to the A-V node which causes ventricular
contraction. The result is first an atrial contraction then, after a few millisecond delay,
the ventricular contraction. A very basic rendition of the heart is laid out in Fig. 17.1.
Our model of the four-chambered heart (Fig. 17.2) is constructed to respond to
changes in blood demand and to disease. A volume of blood is pumped through
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_17,
© Springer International Publishing Switzerland 2014
141