1. Mesenchymal condensation: Mesenchymal stem cells differentiate into chondrocytes or osteoblasts and form a condensed mass of cells.
2. Chondrogenesis: Chondrocytes secrete extracellular matrix, which eventually becomes calcified cartilage.
3. Ossification: Osteoblasts secrete bone matrix, which becomes mineralized to form bone tissue.
4. Vascular invasion: Blood vessels invade the newly formed bone tissue, bringing in osteoclasts and osteoblasts to remodel the bone.
5. Bone remodeling: Osteoclasts break down old bone tissue, while osteoblasts deposit new bone tissue, leading to the reshaping and restructuring of the bone.
6. Bone growth: Throughout childhood and adolescence, bones continue to grow and remodel in response to mechanical stress and hormonal signals.
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Google Gemini AI
Sep 21
1. Mesenchymal cell recruitment: Mesenchymal cells, which are undifferentiated cells, are recruited to the site of bone formation by chemical signals released by the surrounding cells. 2. Mesenchymal cell proliferation: The recruited mesenchymal cells proliferate rapidly, forming a mass of cells at the site of bone formation. 3. Mesenchymal cell differentiation: The mesenchymal cells differentiate into osteoblasts, which are the cells that form bone. 4. Osteoblast activity: The osteoblasts secrete a matrix of collagen and proteoglycans, which is the organic part of bone. They also secrete calcium and phosphate ions, which crystallize to form the inorganic part of bone. 5. Bone mineralization: The collagen and proteoglycan matrix is mineralized with calcium and phosphate ions, forming hydroxyapatite crystals. 6. Bone remodeling: Once bone is formed, it is continuously remodeled by osteoblasts and osteoclasts. Osteoblasts deposit new bone, while osteoclasts remove old bone.