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The periosteum is a membrane that covers the outer surface of all bones, [1] except at the articular surfaces (i.e. the parts within a joint space) of long bones. (At the joints of long bones the bone's outer surface is lined with "articular cartilage", a type of hyaline cartilage.)
Diameter of canaliculi in human bone is approximately 200 to 900 nm. [1] In bovine tibia diameter of canaliculi was found to vary from 155 to 844 nm (average 426 nm). [ 2 ] In mice humeri it varies from 80 to 710 nm (average 259 nm), while diameter of osteocytic processes varies from 50 to 410 nm (average 104 nm).
Osteoblasts, the bone-forming cells, secrete the organic components of bone matrix [osteoid] and then initiates its mineralization. As osteoblasts become surrounded by the bone matrix, they differentiate into osteocytes, which reside in the lacunae and maintain bone tissue. The osteocytes connect to each other and the Haversian canal via tiny ...
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone. Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes.
The percentage of dead osteocytes in bone increases with age from less than 1% at birth to 75% after age 80. [23] Osteocyte apoptosis is thought to be related to decreased mechanotransduction, which possibly leads to the development of osteoporosis. [24] Apoptotic osteocytes release apoptotic bodies expressing RANKL to recruit osteoclasts. [12]
Bone tissue is mineralized tissue of two types, cortical bone and cancellous bone. Other types of tissue found in bones include bone marrow, endosteum, periosteum, nerves, blood vessels and cartilage. In the human body at birth, approximately 300 bones are present.
The periosteum is formed around the trabeculae by differentiating mesenchymal cells. The primary center of ossification is the area where bone growth occurs between the periosteum and the bone. Osteogenic cells that originate from the periosteum increase appositional growth and a bone collar is formed.
Age, bone type, drug therapy and pre-existing bone pathology are factors that affect healing. The role of bone healing is to produce new bone without a scar as seen in other tissues which would be a structural weakness or deformity. [2] The process of the entire regeneration of the bone can depend on the angle of dislocation or fracture.