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The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix. Near the surface of the compact bone, the lamellae are arranged parallel to the surface; these are called circumferential lamellae.
It consists of multiple microscopic columns, each called an osteon or Haversian system. Each column is multiple layers of osteoblasts and osteocytes around a central canal called the osteonic canal. Volkmann's canals at right angles connect the osteons together. The columns are metabolically active, and as bone is reabsorbed and created the ...
The prefix osteo-indicates that the protein is expressed in bone, although it is also expressed in other tissues. The suffix -pontin is derived from "pons," the Latin word for bridge, and signifies osteopontin's role as a linking protein. Osteopontin is an extracellular structural protein and therefore an organic component of bone.
This constitutes the so-called capsule of the space. Each lacuna is generally occupied by a single cell, but during the division of the cells, it may contain two, four, or eight cells. Lacunae are found between narrow sheets of calcified matrix that are known as lamellae ( / l ə ˈ m ɛ l i / lə- MEL -ee ).
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 mesenchymal stem cells, is essential to support the metabolic activity of ...
Osteonectin is a 40 kDa acidic and cysteine-rich glycoprotein consisting of a single polypeptide chain that can be broken into 4 domains: 1) a Ca 2+ binding domain near the glutamic acid-rich region at the amino terminus (domain I), 2) a cysteine-rich domain (II), 3) a hydrophilic region (domain III), and 4) an EF hand motif at the carboxy terminus region (domain IV).
Osteocytes synthesize sclerostin, a secreted protein that inhibits bone formation by binding to LRP5/LRP6 coreceptors and blunting Wnt signaling. [ 16 ] [ 7 ] Sclerostin, the product of the SOST gene, is the first mediator of communication between osteocytes, bone forming osteoblasts and bone resorbing osteoclasts, critical for bone remodeling ...
Osteoblasts begin the process of forming bone tissue by secreting the osteoid as several specific proteins. The osteoid and its adjacent bone cells have developed into new bone tissue when it becomes mineralized. Osteoid makes up about fifty percent of bone volume and forty percent of bone weight. It is composed of fibers and ground substance.