Bone Formation, Growth, Remodeling, and Fracture Repair
이 집합의 용어 (20)
Osteogenesis is the process of bone formation, including the development, growth, remodeling, and repair of bones.
Endochondral and Intramembranous osteogenesis are the two main types of bone formation.
Bone forms by replacing a cartilage model; it is responsible for forming most bones, especially long bones.
Bone develops directly from mesenchymal tissue without a cartilage stage, mainly forming flat bones like the skull.
Osteoblasts build bone, osteocytes maintain bone, and osteoclasts break down bone.
Osteoblasts synthesize and secrete the bone matrix and initiate mineralization.
Osteocytes are mature bone cells that maintain the bone matrix and communicate mechanical stress.
Osteoclasts resorb bone by breaking down the mineral matrix during remodeling and repair.
Mechanical stress, calcium ion levels, and hormonal signals stimulate bone remodeling in either formation or resorption.
Low plasma calcium triggers bone resorption to release calcium; high calcium promotes bone formation to store calcium.
Parathyroid hormone (PTH) increases calcium by stimulating osteoclasts; calcitonin lowers calcium by inhibiting osteoclasts.
Formation of a hematoma at the fracture site to stop bleeding and provide a foundation for healing.
Fibroblasts and chondroblasts produce a soft callus of collagen and cartilage to bridge the fracture gap.
Osteoblasts replace the soft callus with a hard bony callus of spongy bone, stabilizing the fracture.
The bony callus is remodeled into compact bone, restoring the bone's original shape and strength.
Increased mechanical stress stimulates osteoblast activity to strengthen bone; lack of stress leads to bone resorption.
Osteocytes detect mechanical load and signal osteoblasts and osteoclasts to adjust bone remodeling accordingly.
Calcium is essential for bone mineralization, strength, and serves as a critical ion in many physiological processes.
Parathyroid hormone (PTH) stimulates osteoclasts to resorb bone and release calcium into the blood.
Calcitonin inhibits osteoclast activity, reducing bone resorption and lowering blood calcium levels.