11.2  Movement

big ninja

Essential Idea:

The roles of the musculoskeletal system

are movement, support and protection


  • Bones and exoskeletons provide anchorage for muscles and act as levers
  • Synovial joints allow certain movements but not others
  • Movement of the body requires muscles to work in antagonistic pairs
  • Skeletal muscle fibres are multinucleate and contain specialised endoplasmic reticulum
  • Muscle fibres contain many myofibrils
  • Each myofibril is made up of contractile sarcomeres
  • The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments
  • ATP hydrolysis and cross bridge formation are necessary for the filaments to slide
  • Calcium ions and the proteins tropomyosin and troponin control muscle contractions


  • Antagonistic pairs of muscles in an insect leg


  • Annotation of a diagram of the human elbow
  • Drawing labelled diagrams of the structure of a sarcomere
  • Analysis of electron micrographs to find the state of contraction of muscle fibres