B5a The skeleton

B5a The skeleton

1. Broken bones

   • simple fracture
     • when the bone breaks cleanly
   • greenstick fracture
     • when the bone dose not break completely
   • compound fracture
     • when the broken bone shatters or breaks the skin and muscle
   • when the bones are broken or damaged they can become infected becsause there living things. however they can re-grow and repair themselves

2. types of skeleton

   • internal skeleton
     • provides shape and a framework for the body
     • grows with the body
     • are easy for muscles to attach to
     • has joints for flexibility
     • Humans skeletons are made of bone with some cartilage
     • Some animals have internal skeletons made entirly from cartilage
   • exoskeleton
     • heavy for protection
     • inflexible
     • an animal must shed its exoskeleton for it to grow
     • made from chitin

3. Joints

   • A joint is where two or more bones meet
   • fixed joint
     • the skull is a fixed joint, where bony plates are fused together
   • synovial joints
     • hinge joints - bend in one direction only
       • the elbow
       • the knee
     • ball and socket joints - allow a wide range of movement including rotation
       • shoulder
       • hip
     • ellipisodal - can move up, down, side to side but no rotation
       • the wrist

4. structure of a long bone

   • hollow shaft
   • they weight less and are stronger than other bones
   • the head of the bone is covered in cartilage, to lubricate movement against other bones
   • contains bone marrow and blood vessels
   • the head of a bone contains air pockets

5. growing bones

   • in a foetus all the bones are made from cartillage
   • during growth the cartillage is replaced with calcium and phosphorus that makes it hard. this is called ossification

6. the arm

   • the arm ahs two muscles, the bicep and the tricep. these are antagonistic muscles
     • Antagonistic muscles work together. as one contracts the other relaxes and vice versa