An osteocytea star-shaped type of bone cellis the most commonly found cell in mature bone tissueand can live as long as the organism Mature bone cell. In mature bone, osteocytes and their processes reside inside spaces called lacunae Latin for a pit and canaliculirespectively.
Osteocytes are networked to each other via long cytoplasmic extensions that occupy tiny canals called canaliculi, which are used "Mature bone cell" exchange of nutrients and waste through gap junctions. Although osteocytes have reduced synthetic activity and like osteoblasts are not capable of mitotic division, they are actively involved in the routine turnover of bony matrix, through various mechanosensory mechanisms.
They destroy bone through a rapid, transient relative to osteoclasts mechanism called osteocytic osteolysis. Hydroxyapatitecalcium carbonate and calcium phosphate is deposited around the cell. Osteocytes have a stellate shape, approximately 7 micrometers deep and wide by 15 micrometers in length. The fossil record shows that osteocytes were present in bones of jawless fish to million years ago.
During bone formation, an osteoblast is left behind and buried in the bone matrix as an "osteoid osteocyte", which maintains contact with other osteoblasts through extended cellular processes. Osteocytes appear to be enriched in proteins that are resistant to hypoxia, which appears to be due to their embedded location and restricted oxygen supply.
Although osteocytes are relatively inert cells, they capable of molecular synthesis and modification, as well as transmission of signals over long distances, in a way similar to Mature bone cell nervous system. Osteocytes are thought to be mechanosensor cells that control the activity of osteoblasts and osteoclasts within a basic multicellular unit BMUa temporary anatomic structure where bone remodeling occurs. Osteocyte specific proteins such as sclerostin have been shown to function in mineral metabolism, as well as other molecules such as PHEXDMP-1MEPEand FGFwhich are highly expressed by osteocytes and regulate phosphate and biomineralization.
The osteocyte is an important regulator of bone mass and a key endocrine regulator of phosphate metabolism.
Mechanical loading increases osteocyte viability in vitroand contributes to solute transport through the lacuno-canalicular system in bone, which enhances oxygen and nutrient exchange and diffusion to osteocytes.
Mechanical stimulation of osteocytes results in opening of hemichannels to release PGE2 and ATP, among other biochemical signaling molecules, which play a crucial role in maintaining the balance between bone formation and resorption. From "Mature bone cell," the free encyclopedia. Osteocyte Transverse section of a bone. The Journal of Biophysical and Biochemical Cytology. Archives of Biochemistry and Biophysics.
How Osteoblasts Become Osteocytes". Journal of Bone and Mineral Research. Cell and Tissue Research. Ann N Y Acad Sci. The Journal of Clinical Endocrinology and Metabolism. Communicative and Integrative Biology. Implications for bone remodeling". Mature bone cell of Dental Research. Primary bone intramembranous endochondral.
Osteon Haversian canals Volkmann's canals
Ossification Primary bone intramembranous endochondral. trabecula: a small mineralized spicule that forms a network in spongy bone; epiphysis: the rounded end of any long bone; osteocyte: a mature bone cell involved. OSTEOCLASTS are large cells that dissolve the bone. They come from the bone marrow and are related to white blood cells. They are formed from two or more.
An osteocyte, a star-shaped type of bone cell, is the most commonly found cell in mature bone tissue, and can live as long as the organism itself.
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