Role of The Skeleton in Movement
- The effective movement of the human body requires both muscle and an incompressible skeleton
- Bones and exoskeletons provide anchorage for muscles and act as levers
- Vertebrates have internal bones, called an endoskeleton, to support their bodies from the inside with tissues surrounding the bone
- Many organisms, such as arthropods, have external skeletons called exoskeletons which are found on the outside of the organism to protect the internal tissues
- Arthropods that have exoskeletons include:
- Crustaceans
- Insects
- Arachnids
- Centipedes and millipedes
- Molluscs
- Exoskeletons are made of polysaccharides called chitin
- Key features of both exo and endo skeletons is that they provide support for the body of the organism whilst also facilitating movement
- Exoskeletons also provide protection for the body's soft tissues within
- Muscles are anchored to the skeleton either on the inside (as with exoskeletons) or the outside (as with endoskeletons) and the presence of pivot points means that skeletons act as levers transferring the size and direction of force
- Levers have a point of effort, a point of load and a pivot point called the fulcrum
- These same three features are seen in skeletons
Levers and Skeleton Diagram
Muscles attach to bones at the joints creating a system of levers
- Arthropod exoskeletons also use the mechanisms of leverage in the same way as animals use with endoskeletons
- They utilise jointed legs and jointed body parts with muscles attached in antagonistic pairs