Vasodilation is the process by which blood vessels widen, allowing for increased blood flow. This occurs when the smooth muscles in the vessel walls relax, often in response to various signals such as heat, low oxygen levels, or certain hormones. It plays a crucial role in regulating blood pressure and ensuring that tissues receive adequate oxygen and nutrients. During vasodilation, the diameter of the blood vessels increases, which can help lower blood pressure and improve circulation. This process is important in various physiological responses, including exercise, where increased blood flow is needed to supply active muscles, and in thermoregulation, where it helps release heat from the body.