The skeletal system has five main functions which are as follows:
1. Support. The skeleton provides a mobile, structural framework giving the body its overall shape. It allows for attachment of tendons and some muscles.
2. Protection. The skeleton creates cavities which protect internal organs, for example the cranium protects the brain whereas the ribcage protects the heart and lungs.
3. Movement. Individual bones are rigid but with muscles attached and a system of joints, the body achieves movement when the muscles contract and pull on the bones.
4. Blood cell production. In the bones of the developing fetus and in some adult bones for example the pelvis, breastbone, and skull and at the ends of thighbones, red bone marrow is present. This produces red and white blood cells and platelets, a process called hemopoiesis.
5. Mineral storage. Bone marrow is able to store minerals especially calcium and phosphorus. Minerals are released into the body as required in order to maintain homeostasis.
The adult skeleton consists of 206 bones which are grouped into two main divisions namely the axial skeleton and the appendicular skeleton.
The axial skeleton consists of 80 bones which include the cranium, the vertebral column and the rib cage including the sternum. This forms the frame to which the appendicular skeleton of 126 bones is attached to. The appendicular skeleton includes the upper and lower limbs and the bones which act as attachments for them such as the scapula and clavicles, and the pelvic girdles.
Axial skeleton Appendicular Skeleton
Vertebral column Scapula
Ribs Ulna and Radius...