the Vascular System
differential effects on large and small arteries, changes in taper factors
from normal can be quite pronounced.
Schematic diagram illustrating a blood vessel with geometric taper. The vessel
diameter narrows with increasing distance
away from the origin. Geometric taper, an
distance, is normally calculated from the change in cross-
Alternative formula to calculate taper factor per unit length, or
expressed as follows:
The reported values of
obtained for the abdominal aorta, the iliac,
femoral and carotid arteries are shown in Table 2.2.1. These are
measured in vivo at a mean arterial pressure of about 90 mmHg. The
average body weights of dogs used are about
It is obvious from
these data that the taper factor is smaller for smaller vessels.
arteries have the least taper. They are thus the best approximation to a
geometrically uniform cylindrical vessel.
Area ratios calculated for vascular branching junctions were about
at the aortic arch, and 1.05 at the aorto-iliac junction (Li et al.,
1984). These values are slightly larger than
consequences of these are discussed in Chapter