Neuromuscular junctions in fruit flies
Our nerves send chemical signals to muscle fibers in order to stimulate muscle contraction, resulting in movement and locomotion. For this to happen, the ends of nerve fibers must be in very close proximity to the muscle—and we mean very close: The average space of a neuromuscular junction is just 30 nanometers, which is over 2,600-times smaller than the width of a human hair. In this neuromuscular junction of a fruit fly, nerve terminals (in red) can be seen intermingling with structural components (in green and blue). Diseases like Duchenne muscular dystrophy destabilize the structural integrity of neuromuscular junctions, greatly impairing muscle movement and strength.
Image by Vanessa Auld, University of British Columbia, Canada.