ANAT 261 Lecture Notes - Bone Resorption, Acromegaly, Calcium Metabolism

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Document Summary

Intramembranous ossification is typical of flat bones (part of mandible, maxilla, occipital, temporal and parietal bones). This takes place within plates of mesenchymal cells: first, groups of mesenchymal cells differentiate into osteoblasts. Endochondral ossification makes long bones in the body. Typically, this takes place on hyaline cartilage with a similar shape of the bone to be formed. Cartilage is surrounded by the perichondrium everywhere but articulated surfaces (the future heads of the bones) Formation of primary ossification center: the primary ossification center forms at the level of the diaphysis (middle of the bone, here, the perichondrium is transformed into periosteum, which deposits bone. These blood vessels come from the perichondrium, which is turning into the periosteum. This invasion pushes the bone collar inwards: the osteoprogenitor cells become osteoblasts, which then divide and secrete ecm. Formation of secondary ossification center: this takes place at the epiphysis of the future bone.