What is the smallest branch of an artery that connects arteries to capillaries called?

The smallest branch of an artery that connects arteries to capillaries is called an arteriole. Arterioles are critical components of the circulatory system as they regulate blood flow to capillary beds, which are responsible for nutrient and gas exchange at the tissue level. By constricting and dilating, arterioles play a key role in controlling blood pressure and directing blood flow according to the metabolic needs of tissues.

Veins refer to blood vessels that carry deoxygenated blood back to the heart, which does not align with the function of connecting arteries to capillaries. Venules are small vessels that collect blood from capillaries and transport it to veins, not arteries. Capillaries themselves are the smallest blood vessels where exchange occurs but do not serve as branches of arteries. This makes arterioles the correct answer as they uniquely serve the purpose of connecting the arterial system to the capillary network.