Assertion: periosteum's layer | /r/HasProperty | their progenitor cells
Facets:
Source sentences:
text: The inner layer contains numerous osteoblasts and osteoprogenitor cells, and the outer layer is composed of dense collagen fiber, fibroblasts, and their progenitor cells ; osteogenic progenitor cells from the periosteal cambium layer may work with osteoblasts in initiating and driving the cell differentiation process of bone repair characterized by the development of the initial fracture callus and subsequent remodeling.
text: The periosteum is a highly vascular tissue and is comprised of 2 layers: the inner cellular or cambium layer that contains numerous osteoblasts and osteoprogenitor cells  and an outer fibrous layer composed of dense collagen fibre and fibroblasts and their progenitor cells .