Table 4.

A comparison of the effect of arteriole or capillary constriction, alone or combined, upon total vascular resistance

	Total resistance change ratio (% flow decrease)
% change in diameter (whole arteriole or at pericyte soma	Arteriole constriction	Capillary constriction (as in Table 1)	Combined constriction
10%	1.097 (8.8%)	1.185 (16%)	1.282 (22%)
20%	1.286 (22%)	1.488 (33%)	1.773 (44%)
30%	1.688 (41%)	2.024 (51%)	2.713 (63%)
40%	2.660 (62%)	3.083 (68%)	4.744 (79%)

Effect on the total resistance of the vascular bed (arteriole + capillaries + venule), and on blood flow through the vascular bed (shown in brackets as a percentage decrease), of constriction of either the whole arteriole, or of capillaries (separated by 40 μm) at pericyte somata, or of both, by the percentages shown in the left column. For these calculations, arterioles were assumed to have a baseline diameter of 12.4 μm (Hall et al., 2014), and the baseline dilatation at pericyte somata was set to the average of the values in Table 1 (1.157). All calculations used Poiseuille's law and the dependence of viscosity on vessel diameter.