Vasodilators are medications that open (dilate) blood vessels. They affect the muscles in the walls of your arteries and veins, preventing the muscles from tightening and the walls from narrowing.Vasodilation is a widening of blood vessels that results from relaxation of the muscular walls of the vessels. What widens in vasodilation is actually the diameter of the interior (lumen) of the vessel. The opposite of vasodilation is vasoconstriction. Leafy greens like spinach and collard greens are high in nitrates, which your body converts into nitric oxide, a potent vasodilator. Eating nitrate-rich foods may help improve circulation by dilating blood vessels, allowing your blood to flow more easily.
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels.
When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output[further explanation needed]. Therefore, dilation of arterial blood vessels (mainly the arterioles[citation needed]) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). In addition, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation).
Endogenous substances and drugs that cause vasodilation are termed vasodilators. Such vasoactivity is necessary for homeostasis (keeping the body running normally).