Vasoconstriction and Vasodilation summary

Just wanted to confirm this one last time:

during sympathetic N.S. activation
Vasoconstriction (occurs at digestion organs, decreases radius)
-a decrease in radius=decrease in flow rate (French guy Pname equation)
-increased resistance=higher pressure

Vasodilation (occurs at skin, more important organs)
-increase in radius=increase in flow rate
-decreased resistance=lower pressure

Pressure=flow*resistance

Anything else I need to know about this?