BIOL 243 Lecture Notes - Lecture 9: Endochondral Ossification, Intramembranous Ossification, Hyaline Cartilage
28 Sep 2016
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Ossification (osteogenesis)= process of bone tissue formation. Formation of bony skeleton: begins in 2nd month of development. Postnatal growth development: until early adulthood. Endochondral ossification= bone forms by replacing hyaline cartilage: bones called cartilage (endochondral) bones, forms most of skeleton. Intramembranous ossification= bone develops from fibrous membrane: bones called membranous bones, forms flat bones. Forms most all bones inferior to base of skull (except clavicles) Begins in late 2nd month of development. Requires breakdown of hyaline cartilage prior to ossification. Begins at primary ossification center in center of shaft: blood vessel infiltration of perichondrium converts it to periosteum--> underlying cells change it to osteoblasts. Bone collar forms around diaphysis of cartilage model. Central cartilage in diaphysis calcifies, then develops cavities. Periosteal bud invades cavities --> formation of spongy bone. Forms frontal, occipital, temporal, and parietal bones and clavicle. Begins within fibrous ct membranes formed by mesenchymal cells. Lamellar bone replaces woven bone and red marrow appears.
