Chondrocytes (from Greek chondros cartilage + kytos cell) are the only cells found in cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans. Although chondroblast is still commonly used to describe an immature chondrocyte, use of the term is discouraged, for it is technically inaccurate since the progenitor of chondrocytes (which are mesenchymal stem cells) can also differentiate into osteoblasts. The organisation of chondrocytes within cartilage differs depending upon the type of cartilage and where in the tissue they are found.

Contents 1 Differentiation 2 See also 3 References 4 External links

[edit] Differentiation

From least- to terminally-differentiated, the chondrocytic lineage is:

1. Colony-forming unit-fibroblast (CFU-F)
2. Mesenchymal stem cell / marrow stromal cell (MSC)
3. Chondrocyte
4. Hypertrophic chondrocyte

When referring to bone or cartilage, mesenchymal stem cells (MSC) are commonly known as osteochondrogenic (or osteogenic, chondrogenic, osteoprogenitor, etc.) cells since a single MSC has shown the ability to differentiate into chondrocytes or osteoblasts, depending on the medium. In vivo, differentiation of an MSC in a vascularized area (such as bone) yields an osteoblast, whereas differentiation of an MSC in a non-vascularized area (such as cartilage) yields a chondrocyte. Chondrocytes undergo terminal differentiation when they become hypertrophic during endochondral ossification. This last stage is characterized by major phenotypic changes in the cell.

[edit] See also

• Endochondral ossification
• Intramembranous ossification

[edit] References

• Dominici M, Hofmann T, Horwitz E. "Bone marrow mesenchymal cells: biological properties and clinical applications". J Biol Regul Homeost Agents 15 (1): 28–37. PMID 11388742. 
• Bianco P, Riminucci M, Gronthos S, Robey P (2001). "Bone marrow stromal stem cells: nature, biology, and potential applications". Stem Cells 19 (3): 180–92. doi:10.1634/stemcells.19-3-180. PMID 11359943. 
• Stem cell information

[edit] External links

• Histology at BU 03317loa
• MeSH Chondrocytes

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v • d • e Musculoskeletal system · connective tissue: bone and cartilage (TA A02.0 · GA 2.86-95) Cartilage perichondrium · fibrocartilage callus · metaphysis cells (chondroblast · chondrocyte) types (hyaline · elastic · fibrous) Bone Ossification intramembranous · endochondral Cycle osteoblast · osteoid · osteocyte · osteoclast Types cancellous · cortical Regions subchondral bone · epiphysis · epiphyseal plate/metaphysis · diaphysis · Condyle · Epicondyle Structure osteon / Haversian system · Haversian canals · Volkmann's canals · connective tissue (endosteum · periosteum) · Sharpey's fibres · enthesis · lacunae · canaliculi · trabeculae · medullary cavity · bone marrow Shapes long · short · flat · irregular · sesamoid bone and cartilage navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous signs, proc

v • d • e Human cell types Blood/immune lymphoid: B cell  · T cell (Cytotoxic T cell, Natural Killer T cell, Regulatory T cell, T helper cell) · Natural killer cell myeloid: granulocytes (Basophil granulocyte, Eosinophil granulocyte, Neutrophil granulocyte/Hypersegmented neutrophil)  · Monocyte/Macrophage  · Red blood cell (Reticulocyte)  · Mast cell  · Thrombocyte/Megakaryocyte  · Dendritic cell Endocrine system thyroid (Thyroid epithelial cell, Parafollicular cell)  · parathyroid (Parathyroid chief cell, Oxyphil cell)  · adrenal (Chromaffin cell) · pineal (Pinealocyte) Nervous system glial cells: Glioblast (Astrocyte, Oligodendrocyte) · Microglia Magnocellular neurosecretory cell  · Stellate cell · Boettcher cell pituitary (Gonadotrope, Corticotrope, Thyrotrope, Somatotrope, Lactotroph ) Respiratory system Pneumocyte (Type I pneumocyte, Type II pneumocyte) · Clara cell · Goblet cell · Alveolar macrophage Circulatory system Myocardiocyte · Pericyte Digestive system stomach (Gastric chief cell, Parietal cell) · Goblet cell · Paneth cell G cells · D cells · ECL cells · I cells  · K cells  · S cells Enteroendocrine cells · Enterochromaffin cell · APUD cell liver (Hepatocyte, Kupffer cell) Cartilage/bone/ muscle/ integumentary system bone: Osteoblast · Osteocyte · Osteoclast · teeth (Cementoblast, Ameloblast) cartilage: Chondroblast · Chondrocyte skin/hair: Trichocyte · Keratinocyte  · Melanocyte (Nevus cell) muscle: Myocyte other: Adipocyte  · Fibroblast (corneal keratocyte) · Tendon cell Urinary system Podocyte  · Juxtaglomerular cell  · Intraglomerular mesangial cell/Extraglomerular mesangial cell  · Kidney proximal tubule brush border cell  · Macula densa cell Reproductive system male (Spermatozoon, Sertoli cell, Leydig cell)  · female (Ovum) see also list of distinct cell types in the adult human body