Arterioles are small blood vessels that branch off from arteries and lead to capillaries. They play a crucial role in regulating blood flow and blood pressure within the circulatory system. By constricting or dilating, arterioles can control the amount of blood that reaches different tissues and organs, ensuring that they receive the necessary oxygen and nutrients. These tiny vessels are lined with smooth muscle, which allows them to change their diameter in response to various signals from the body. This ability to adjust helps maintain homeostasis and supports the overall function of the cardiovascular system, including the larger arteries and capillaries.