When we think of blood vessels, we imagine just a few of them. But that's not quite the end of the story. The human body is a work of art, armed with thousands and thousands of capillaries, all connected and functions as a system. To isolate the vessels, red plasticizer is pumped into the blood vessels of the arm. After it sets up, acid is used to dissolve away the tissue to reveal a skeletal system of capillaries.