Intramembranous process
Connective tissue forms (week 5), mesoderms cell numberincreases, some mesoderm cells differentiate into osteoblast, osteoblasts forma semi solid mass containing osteoids, these osteiods are calcified, additionlayers are then added on, this process is continued, altering spongy andcompact bone, examples of bones formed from this process: Skull, mandible,clavicles
Endochondral Process
Hyaline cartilage is laid down by chondroblast (week 6),cartilage cells in center multiply squeezing the matrix into thin bars andplates, blood vessels penetrate outer later, perchondrial cells change intoosteoblasts, this layes down a bone collar around center, cartilage matrixescalcified, blood vessels penetrate collar, osteoblasts are brough into hyaline modeland lay down osteoid, osteoid is calcified in columns, making trabeculae,trabeculae will narrow forming canaliculi by end, lamellae is laid down betweentrabeculae, center canal will narrow making Haversian Canal.
