The Skeleton and Muscles

  • The functions of the skeleton are support, protection and movement.
  • Muscles are attached to bones. When they contract they alow us to move.
  • Bone is made of living cells. and calcium compounds The living part of the bone lays down the non-living part.
  • All vertebrates have a spine made up of vertebrae.


  • A joint is where 2 bones come together, e.g. the elbow or the knee.
  • Fused joints do not allow movement, e.g. the bones of the skull.
  • Ball and socket joints allow movement in any direction, eg the shoulder and the pelvis.
  • Hinge joints allow movement in one direction only, e.g. the knee.

Ligaments and Tendons

  • Ligaments join bone to bone.
  • Cartilage acts as a shock absorber between bones.
  • Synovial fluid acts as a lubricant.
  • Tendons join muscle to bone.

Antagonistic Muscles

  • Antagonistic muscles are pairs of muscles that pull in opposite directions, e.g. the biceps and triceps of the arm.
  • To raise the arm, the biceps contracts and the triceps relaxes. To lower the arm, the triceps contracts and the biceps relaxes.