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Endochondral ossification is responsible for development of most bones including long and short bones, [4] the bones of the axial (ribs and vertebrae) and the appendicular skeleton (e.g. upper and lower limbs), [5] the bones of the skull base (including the ethmoid and sphenoid bones) [6] and the medial end of the clavicle. [7]
Diagram showing stages of endochondral ossification. Endochondral ossification is the formation of long bones and other bones. This requires a hyaline cartilage precursor. There are two centers of ossification for endochondral ossification. The primary center. In long bones, bone tissue first appears in the diaphysis (middle of shaft).
The process of endochondral ossification, which converts the cartilage models into bone, begins by the twelfth week of embryonic development. At birth, ossification of much of the bone has occurred, but the hyaline cartilage of the epiphyseal plate will remain throughout childhood and adolescence to allow for bone lengthening.
Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling.In osteology, bone remodeling or bone metabolism is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).
Endochondral ossification is the process of forming bone from cartilage and this is the usual method. This form of bone development is the more complex form: it follows the formation of a first skeleton of cartilage made by chondrocytes, which is then removed and replaced by bone, made by osteoblasts. Intramembranous ossification is the direct ...
Chondroblasts, or perichondrial cells, is the name given to mesenchymal progenitor cells in situ which, from endochondral ossification, will form chondrocytes in the growing cartilage matrix. Another name for them is subchondral cortico-spongious progenitors. [1] They have euchromatic nuclei and stain by basic dyes.
An ossification center is a point where ossification of the hyaline cartilage begins. The first step in ossification is that the chondrocytes at this point become hypertrophic and arrange themselves in rows. [1] The matrix in which they are imbedded increases in quantity, so that the cells become further separated from each other.
Example of bone deformation. Deletion of the Trsp gene in osteochondroprogenitor cells results in abnormal bone growth, delayed ossification, chondronecrosis and dwarfism. General Trsp gene deletion is lethal to the embryo. The results of this research was used as a model for Kashin-Beck disease.