Capillaries: The Tiny Vessels Vital to Blood Circulation

The capillaries.

The capillaries are tiny blood vessels that connect the arteries and veins. They are so thin that red blood cells have to squeeze through them in single file. Despite their small size, capillaries are responsible for the exchange of oxygen and nutrients between the blood and the tissues. The arteries carry blood away from the heart, while the veins carry blood back to the heart. The capillaries are located between the arteries and veins and allow for the exchange of substances between the blood and the tissues.