The relaxation of blood vessels, especially the arteries, making them wider and leading to increased blood flow or reduced blood pressure.
An increase in the diameter of blood vessels, especially arteries. This results from activation of the vasomotor center in the brain, which brings about relaxation of the arterial walls and a consequent lowering of blood pressure.
Dilatation of blood vessels, especially small arteries and arterioles.
The expansion of the internal diameter of a blood vessel, brought about by the relaxation of smooth muscle in the vessel wall, leading to an augmentation of blood flow.