why is it so that blood flows in spurts in veins while it flows in large amounts through the arteries??

Blood flows with lesser pressure in veins as compared to arteries, because arteries receive blood from heart. Veins have larger lumen and have valves also to prevent back flow  of blood to the body parts. Blood spurts when arteries are cut.  Arterial cut causes the blood to bleed out at a rapid, intermittent rate as compared to venous bleeding.