Credit: Michael Bastiani, University of Utah.
Nerve cells glow fluorescent green in these microscope photographs showing part of a cross section of a tiny nematode worm. The horizontal green linear feature near the bottom of each photo is the worm equivalent of the spinal cord, while a secondary nerve cord is the horizontal green line near the top. The vertical green line in the left photo is an unbroken axon, the long, wire-like portion of a single nerve cell. The right photograph shows how the nerve cell has broken in a mutant worm lacking a protein needed to make nerves flexible. The object at the end of the broken nerve is a "growth cone," which is evidence the broken nerve attempting to repair itself.