120
The Body Electric
power of osteogenesis, or bone formation. After a fracture, these cells are
somehow turned on. They begin to divide and some of the daughter
cells turn into osteoblasts, cells that make the collagen fibers of bone.
Apatite crystals then condense out of the blood serum onto the fibers.
The other tissue that forms new bone to heal a fracture is the marrow.
Its cells dedifferentiate and form a blastema, filling the central part of
the fracture. The blastema cells then turn into cartilage cells and later
into more osteoblasts.
This process is true regeneration, following the
same sequence of cell changes as the regrowing salamander limb.
Whatever a physician does to repair a fracture, he or she must protect
the periosteum and marrow cavity from harm. Unfortunetely, too often