overview of skeletal system

• provides scaffold to support the weight of the rest of the body
• facilitates movement by being points of attachment for muscles. muscle contraction allows for movement. bones articulate where they meet to move relative to one another. articulation allows varying degrees of movement depending on the bones involved. so, the skeleton determines the extend of movement
• protects vital organs. for example :

  • brain encased in cranium
  • spinal cord contained within spinal canal formed by vertebrae
  • heart and lungs protected by ribs
  • reproductive organs and bladder by pelvis
• stores and releases minerals and fats. bones act as storage organ for mineral salts and fats. the main minerals stored within are calcium, phosphorus, sodium and potassium. they can be distributed to other regions of the body by the circulatory system. for example if a pregnant woman's diet lacks calcium, it can be removed from her skeleton and used for growth of bones in the developing foetus
• produces blood cells. red marrow in certain bones contain stem cell which can differentiate into blood cell. factors in the cells' environment determines the type of blood cell (red, white or platelet)
• flat bones protects internal organs
• long bones support weight and allows movement. they are longer than they are wide
• sesamoid bones protects tendons
• irregular bones protects different structures due to their variable nature
• short bones provides stability and some movement. they are as wide as they are long
• axial skeleton consists of bones that lie around the central axis of the body. it is made of bones that form the skull, vertebral column, ribs and sternum
• axial skeleton provides the main support for erect posture and protection of the central nervous system and organs within the thorax
• appendicular skeleton consists of bones of the upper and lower limbs, pectoral (shoulder) girdle and pelvic (hip) girdle. the girdles allow for articulation of limbs with the axial skeleton