The skeletal system consists of 206 bones and their associated tissues, including the cartilage, ligaments, tendons and joints. Its functions are supporting the body and protecting the vital organs. It also serves as anchorage for the action of muscles.
The tubular structure of bones allows maximum support for the entire body. Parts of the skeletal system are the skull, rib cage and sternum, and the pelvis. These respectively protect the brain, the heart and lungs, and the reproductive organs. It also comprises joints or articulations that permit different degrees of movement. The bones cover the marrow tissue, which is responsible for forming blood cells.
The skeletal system is divided into two divisions. The axial division is composed of 80 bones that make up the skull, vertebral column and rib cage. It supports and protects organs within the dorsal and ventral body cavities. It also provides the framework for attaching muscles that carry out respiratory movements, adjust the position of the head, neck and trunk, and anchor the appendicular bones. The appendicular division is composed of 126 bones that make up the girdles and appendages in the body.
Bones are categorized into long, short, flat, irregular, sesamoid and wormian. They are classified based on shape and size. Examples of long bones are the radius, humerus, femur and ulna. Examples of short bones are the ankle bones and wrist bones.