Sarcomeres/Diagram

• I bands/light bands


  areas where the actin and myosin filaments DO NOT overlap
• A bands/dark bands


  thick myosin filaments are present, the edges are darker as both filaments overlap
• Z line


  found at the centre of each light band
• H zone


  lighter coloured region found in centre of each dark/A band; only myosin present
• during contraction

  myosin pulls actin inwards, light/I band narrows, Z lines move closer, H zone narrows
• what is a sarcomere


  the distance between adjacent Z lines