Arterioles are small blood vessels that branch out from arteries and lead to capillaries. They play a crucial role in regulating blood flow and pressure within the circulatory system. By constricting or dilating, arterioles can control the amount of blood that reaches different tissues in the body. These tiny vessels have muscular walls that allow them to adjust their diameter. This ability helps maintain proper blood pressure and ensures that organs receive the right amount of oxygen and nutrients. Overall, arterioles are essential for efficient blood circulation and overall health.