The Skeleton and movement

Our sleleton has three main functions:

  • To support  and protect organs in the body
  • To allow movement

The adult skeleton is composed of 206 bones although we are born with 270 bones (the number gets less because some of the bones fuse together as we grow)

Skeleton

Muscles hold the bones in place and also cause the bones to move.

The bones are attached to the muscles by tendons (the most well know of which is the achilles tendon in the heel)

Muscles usually work in pairs (antagonistic muscles)

Example: The biceps and the triceps in the arm
When one muscle contracts the other relaxes.
muscles
To raise the arm: the biceps contact and the triceps relax.
To lower the arm: the biceps relax and the triceps contract.