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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). Chondrocytes multiply and form trebeculae.
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 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]
In the hollow within bones are many other cell types of the bone marrow. Components that are essential for osteoblast bone formation include mesenchymal stem cells (osteoblast precursor) and blood vessels that supply oxygen and nutrients for bone formation. Bone is a highly vascular tissue, and active formation of blood vessel cells, also from ...
Examples of periosteal reactive bone in selected specimens of Triceratops. A periosteal reaction can result from a large number of causes, including injury and chronic irritation due to a medical condition such as hypertrophic osteopathy, bone healing in response to fracture, chronic stress injuries, subperiosteal hematomas, osteomyelitis, and cancer of the bone.
Physiological bone resorption is an integral part of bone functioning, while the bone is constantly growing thanks to two processes — breakdown and formation of bone tissue. [23] Locally, it could be manifested in tooth eruption when the movement of a tooth follicle is followed by an active resorption of jaw bone tissue.
The process of the entire regeneration of the bone can depend on the angle of dislocation or fracture. While the bone formation usually spans the entire duration of the healing process, in some instances, bone marrow within the fracture has healed two or fewer weeks before the final remodelling phase. [citation needed]
Sesamoid bones can be found on joints throughout the human body, including: In the knee—the patella (within the quadriceps tendon). This is the largest sesamoid bone. [4] In the hand—two sesamoid bones are commonly found in the distal portions of the first metacarpal bone (within the tendons of adductor pollicis and flexor pollicis brevis).