SUSUMU NISHINAGA / SCIENCE PHOTO LIBRARY SUSUMU NISHINAGA / SCIENCE PHOTO LIBRARY
Blood vessels. Coloured scanning electron micrograph (SEM) of a resin cast of the blood vessels of the penis. This network of vessels infiltrate the penis' tissues, supplying them with blood. Gases and nutrients are exchanged between the blood and surrounding tissue via the permeable walls of capillaries. The penis is the male copulatory organ, which mammals also use for urination. The cast was made by injecting resin into the blood vessels, followed by chemical digestion of the surrounding tissue.
Model release not required. Property release not required.