Bone is the type of connective tissue that forms the body s supporting framework, the skeleton. Serve to protect the internal organs from injury. The bone marrow inside the bones is the body's major producer of both red and white blood cells.

The bones of women are generally lighter than those of men, while children's bones are more resilient than those of adults Bones also respond to certain physical physiological changes: atrophy, or waste away.

Bones are generally classified in two ways. When classified on the basis of their shape, they fall into four categories: flat bones, such as the ribs; long bones, such as the thigh bone; short bones, such as the wrist bones; and irregular bones, such as the vertebrae. When classified on the basis of how they develop, bones are divided into two groups: endochondral bones and intramembraneous bones. Endochondral bones, such as the long bones and the bones at the base of the skull, develop from cartilage tissue Intramembraneous bones, such as the flat bones of the roof of the skull, are not formed from cartilage but develop under or within a connective tissue membrane. Although endochondral bones and intramembraneous bones form in different ways, they have the same structure.