break both words down into sections ... 'vaso' is common to both words and that means 'veins' as in a blood vein. Dilation is the 'extension' or 'widening' of something, so vasodilation is the 'widening of the blood vessel system. Constriction means getting smaller or closed off ... so vasoconstriction means ??? It's really simple if you can do this when you are trying to 'understand' a long technical term ... so remember the 'method' the next time you get 'stuck' on your homework.
