Peripheral nerve. Light micrograph of a section through a peripheral nerve. This is a mixed nerve with myelinated axons (dark blue circles), unmyelinated axons (pale-staining regions lacking myelin) and numerous deep-staining nuclei representing Schwann cells. The nerves are supported by connective tissue endoneurium and an outermost perineurium. Magnification: x200 when printed 10 centimetres wide.