Which type of vessel allows for exchange between blood and body cells?

Capillaries are the small blood vessels that facilitate the exchange of gases, nutrients, and waste products between the blood and body cells. Their structure is specifically designed for this purpose; they have thin walls that are only one cell thick, allowing substances to diffuse easily across the membrane. This diffusion is crucial for delivering oxygen and nutrients to tissues while simultaneously removing carbon dioxide and metabolic waste.

Arterioles, while they do lead to the capillary beds, primarily function to regulate blood flow and pressure and are not directly involved in the exchange process. Venules and veins are responsible for returning blood to the heart and also do not facilitate the direct exchange of materials with body tissues to the extent that capillaries do. Thus, capillaries are uniquely suited for this essential function in the circulatory system.