Osteoblast
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Osteoblast | |
|---|---|
 | |
| Osteoblasts and osteoclasts on trabecula of lower jaw of calf embryo. | |
 | |
| Part of the growing edge of the developing parietal bone of a fetal cat. | |
| Gray's | subject #18 87 |
| MeSH | Osteoblasts |
| Dorlands/Elsevier | o_08/12600120 |
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
An osteoblast (from the Greek words for "bone" and "germ" or embryonic) is a mononucleate cell that is responsible for bone formation. Osteoblasts produce osteoid, which is composed mainly of Type I collagen. Osteoblasts are also responsible for mineralization of the osteoid matrix. Bone is a dynamic tissue that is constantly being reshaped by osteoblasts, which build bone, and osteoclasts, which resorb bone.
Osteogenesis
Osteoblasts arise from osteoprogenitor cells located in the periosteum and the bone marrow. Osteoprogenitors are immature progenitor cells that express the master regulatory transcription factor Cbfa1/Runx2.
Osteoprogenitors are induced to differentiate under the influence of growth factors, in particular the bone morphogenetic proteins (BMPs). Aside from BMPs, other growth factors including fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β) may promote the division of osteoprogenitors and potentially increase osteogenesis.
Once osteoprogenitors start to differentiate into osteoblasts, they begin to express a range of genetic markers including Osterix, Col1, ALP, osteocalcin, osteopontin, and osteonectin. Although the term osteoblast implies an immature cell type, osteoblasts are in fact the mature bone cells entirely responsible for generating bone tissue in animals and humans.
Morphology and histological staining
The cytoplasm of osteoblasts appears to be basophilic via normal H&E stain due to presence of large amount of rough endoplasmic reticulum. A large Golgi apparatus is also present in the centre. The nucleus is spherical and large. Osteoblasts can be stained for type 1 collagen or for the production of alkaline phosphatase.
Osteoblasts and osteocytes
Osteoblasts that become trapped in the bone matrix become osteocytes. They cease to generate osteoid and mineralized matrix, and instead act in a paracrine manner on active osteoblasts. They are believed to act in a mechanosensory manner.
External links
Musculoskeletal system, connective tissue: bone and cartilage | |
|---|---|
| Cartilage | perichondrium, fibrocartilage callus, metaphysis
cells (chondroblast, chondrocyte) types (hyaline, elastic, fibrous) |
| Bone | ossification (intramembranous, endochondral, epiphyseal plate)
cycle (osteoblast, osteoid, osteocyte, osteoclast) types (cancellous, cortical) regions (epiphysis, metaphysis, diaphysis) structure (osteon/Haversian system, Haversian canals, Volkmann's canals, endosteum, periosteum, Sharpey's fibres, enthesis, lacunae, canaliculi, trabeculae, medullary cavity, bone marrow) shapes (long, short, flat, irregular, sesamoid) |
de:Osteoblastfr:Ostéoblaste it:Osteoblasto he:אוסטאובלסט nl:Osteoblast ja:骨芽細胞sk:Osteoblast sv:Osteoblast
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
