What are the tiny vessels that join arterioles and venules called?

The tiny vessels that connect arterioles and venules are called capillaries. They play a crucial role in the circulatory system as they are the site of exchange between the blood and tissues. Capillaries are very thin walled, which allows for the efficient transfer of oxygen, carbon dioxide, nutrients, and waste products. By facilitating this exchange, capillaries ensure that cells receive the substances they need for metabolism while removing waste products efficiently. This unique structure and function are what make capillaries essential components of the vascular network in the body.