Vascular Biology, Structure
and
Function
35
Data from Altman and Dittmer
(1961)
have shown that in more than
one hundred mammalian species, the red blood cells are of similar size.
If we compare the size of red cells from various mammals, we find the
perhaps surprising fact that their diameters seem to be rather uniform and
independent of mammalian body size (Table
2.3.2).
Table
2.3.2:
Diameters
of
red blood cells
(RBC)
of
some mammalian species.
2.4
Control Aspects
of
the Vascular System
Homeostasis and overall control of the circulation hinge on the
regulation and control of blood pressure and maintaining adequate
perfusion
to
vital organ vascular beds.
In
addition, the delivery of
oxygen and nutrients and the removal of carbon dioxide and metabolic
waste products are also important considerations.
Controlling blood
pressure is necessary to ensure adequate and on-demand supply
of
blood
to the heart and the brain and, also, to the rest of the body organs.
Control of capillary pressure is necessary to maintain tissue volume and
the composition of the interstitial fluid within desirable ranges
Various receptors of the body are anatomically structured to sense
and monitor the state of the heart and the vascular system. In response to
sensory inputs from these receptors, either individually or in an
integrated manner, both neural and chemical signals induce adjustments
to maintain arterial pressure, blood flow and other hemodynamic
variables.
