Chondrocyte

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Chondrocytes (< Greek chondros cartilage + kytos cell) are the only cells found in cartilage. They produce and maintain the cartilagenous matrix.

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 a MSC in a vascularized area (such as bone) yields an osteoblasts, whereas differentiation of a 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.

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.

[edit] References

• Bone marrow mesenchymal cells: biological properties and clinical applications. PMID: 11388742
• Bone marrow stromal stem cells: nature, biology, and potential applications. PMID: 11359943
• Stem cell information

Bone and cartilage - edit

cartilage: chondroblast, chondrocyte, perichondrium, types (hyaline, elastic, fibrous), fibrocartilage callus, metaphysis bone: ossification (intramembranous, endochondral, epiphyseal plate), cycle (osteoblast, osteoid, osteocyte, osteoclast), types (cancellous, cortical), regions (epiphysis, diaphysis), structure (osteon/Haversian system, Haversian canals, endosteum, periosteum, Sharpey's fibres, lacunae, canaliculi, trabeculae, medullary cavity, bone marrow), shapes (long, short, flat, irregular, sesamoid)