The Skeletal System
Continued from page 1
The bones of the skeleton also serve to store fat and as a reservoir for calcium for the body.  Fat is stored in the yellow bone marrow.  Calcium is stored in the extracellular matrix. New blood cells are formed in the marrow of flat bones.
Where two bones meet at a joint, ligaments hold them together. Ligaments are flexible bands of connective tissue.  Similar bands of connective tissues that attach the muscles to bones are the tendons.
In embryonic development of the human fetus, parts of the skeleton, such as arms and legs, are formed of cartilage. Eventually, the cartilage calcifies into bone. Biologists state that the bones are first "modeled in cartilage" during fetal development before converting to bone.