What is no thicker than human hair and carry blood away from arterires into capilaries?

The structure that is no thicker than a human hair and carries blood away from arteries into capillaries is called an arterioles. Arterioles are small blood vessels that branch from arteries and play a crucial role in regulating blood flow and pressure as they lead into the capillary networks, where the exchange of gases, nutrients, and waste occurs. Their thin walls allow for the efficient transfer of materials between the blood and surrounding tissues.