Uberon Function note : Vascular smooth muscle contracts or relaxes to both change the volume of blood vessels
and the local blood pressure, a mechanism that is responsible for the redistribution
of the blood within the body to areas where it is needed (i.e. areas with temporarily
enhanced oxygen consumption). Thus the main function of vascular smooth muscle tonus
is to regulate the caliber of the blood vessels in the body. Excessive vasoconstriction
leads to hypertension, while excessive vasodilation as in shock leads to hypotension.;