is periosteum living or nonliving?

1 ANSWERS

1. amomipais82
   

   Hi There,
   Bone is a living material, it is vascularized and has nerves going through it.
   
   The formation of bone during the fetal stage of development occurs by two processes: intramembranous and endochondral ossification.
   Intramembranous ossification mainly occurs during formation of the flat bones of the skull; the bone is formed from mesenchyme tissue. The steps in intramembranous ossification are:
   Development of ossification center
   Calcification
   Formation of trabeculae
   Development of periosteum
   [edit]Endochondral ossification
   
   
   Endochondrial ossification
   Endochondral ossification, on the other hand, occurs in long bones, such as limbs; the bone is formed from cartilage. The steps in endochondral ossification are:
   Development of cartilage model
   Growth of cartilage model
   Development of the primary ossification center
   Development of the secondary ossification center
   Formation of articular cartilage and epiphyseal plate
   Endochondral ossification begins with points in the cartilage called "primary ossification centers." They mostly appear during fetal development, though a few short bones begin their primary ossification after birth. They are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones. Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. The diaphysis and both epiphyses of a long bone are separated by a growing zone of cartilage (the epiphyseal plate). When the child reaches skeletal maturity (18 to 25 years of age), all of the cartilage is replaced by bone, fusing the diaphysis and both epiphyses together (epiphyseal closure).
   [edit]Bone marrow
   Bone marrow can be found in almost any bone that holds cancellous tissue. In newborns, all such bones are filled exclusively with red marrow , but as the child ages it is mostly replaced by yellow, or fatty marrow. In adults, red marrow is mostly found in the flat bones of the skull, the ribs, the vertebrae and pelvic bones.

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