What is the smallest blood vessel?

Capillaries are the smallest blood vessels in the body, with a diameter of around 5 to 10 micrometers. They are responsible for connecting arteries and veins and allowing for the exchange of oxygen, nutrients, and waste products between the blood and tissues. Arteries and veins are larger blood vessels and have different functions, with arteries carrying oxygenated blood away from the heart and veins carrying deoxygenated blood towards the heart. Arterioles are small branches of arteries that also play a role in regulating blood flow and blood pressure. Therefore, while they are all important components of the circulatory system, capillaries are specifically the smallest blood vessels.