What is the role of capillary in transport?

In muscles and other body tissues, there are capillary beds which connect arterial supply and venous return.

Arteries end as capillaries in the body tissue, where blood dumps oxygen and nutrients for use by muscles. At this point they are considered arterial. They may also pick up waste products to carry away. By the end of the capillary beds, they are depleted and considered venous. They flow continuously into the veins which flow back to the heart.

The heart sends this blood to the lungs to pick up oxygen and the cycle continues.