Model predicted changes in outer diameter (left) and mean circumferential Cauchy stress (right) of a closed vessel pressurized at 90 mmHg at an axial stretch λz = 1.5. The evolution of these quantities was simulated following a sudden decrease in pressure to 80 mmHg after 2 hours for a vessel with no active smooth muscle (passive), with unchanging active smooth muscle, or with active smooth muscle that adapts. Note that the smooth muscle activity, if any, was triggered at 1 hour, which was 1 hour prior to the step decrease in pressure.