Answer to Question #204062 in Cell Biology for Becky

Question

Describe the main stages in the ossification of a long bone, including the roles of osteoblasts and osteoclasts

Answer 1

I) Cartilage enlarges; Chondrocytes die.

ii) Blood vessels grow into perichondrium; cells convert to osteoblasts; shaft becomes covered with superficial bone.

iii) More blood supply and osteoblasts; produces spongy bone; formation spreads on shaft.

iv) Osteoclasts create medullary cavity; appositional growth.

V) Epiphysis centers calcify; blood and osteoblasts move in; secondary ossification centers.

vi) Epiphysis filled with spongy bone; cartilage remains at joints; epiphyseal plate in metaphysis.