10
Dynamics
of
the Vascular System
structural components of the arterial and venous wall are examined in
rheological terms.
In particular, the physical properties
of
elastin,
collagen, and smooth muscle. The relative contents
of
the wall materials
differentiate arteries from veins, arterioles and capillaries.
Oxygen
is
perhaps the most important component to be transported in
the blood. The formed elements of blood are dealt with, that includes
hemoglobin, red blood cells and plasma. Functional properties of blood
are therefore included in this chapter. Some aspects
of
the circulating
catacholamines and hormones, as well as neural control of the vascular
system are equally important.
Chapter
3
deals with some fundamental concepts for analysis of the
vascular system. The differences in their mechanical properties in large
and small arteries and veins are examined. Their collective contributions
to the overall function are analyzed. The arterial wall does not merely
behave as an elastic vessel, therefore viscoelastic behavior becomes
important.
In this context, the viscous and elastic behavior of the
composite, i.e., the arterial wall, is discussed.
This includes the
characteristics of a viscoelastic material, i.e. creep phenomenon, stress
relaxation, and hysteresis. These aspects are also applied to veins, except
the differences in distending pressures and collapsibility come into play.
Fundamental principles of fluid mechanics that includes classical
laws and governing equations are provided. This includes Poiseuille's
equation, Bernouilli's equation and the determining laminar and turbulent
behavior in terms
of
Reynolds number. This is examined in terms
of
the
rheology of blood flow to the containing vessel properties.
Engineering methods of basic analysis in the time domain, the Fourier
analysis in the frequency domain are also included with examples that
apply to the vascular system.
Chapter
4
deals with the hemodynamics
of
large arteries. Aorta
is
the
largest artery whose distensibility and great compliance facilitates
ventricular ejection in systole. The manner how ventricle and aorta
interact will be explained,
as
well
as
the initial impulse aspect of
ventricular ejection. The pulsatile wave transmission characteristics of
blood pressure and flow and simplified mathematical description, and
fundamentals
of
modeling are included. The description classic
of
the
windkessel model of the arterial system is first introduced.
The
