Cartilage structure

On a larger scale, we have ligaments and cartilage, structures that hold joints together and tie muscle to bone. These too are composed of proteins tough, water-insoluble proteins. Principal among them are the collagens. 

Figure 11.9 Schematic of articular cartilage structure showing the superficial, middle and deep zones, the tidemark boundary between the noncalcified and calcified cartilage layer, and the subchondral bone that underlies the articular cartilage.

Moss M. L. and Moss-Salentijn L. (1983) Verterate cartilages. In Cartilage, Structure, Function and Biochemistry (ed. B. K. Hall). Academic Press, New York, pp. 1-30. 

Poole, A.R. (2001) Cartilage Structure and Function in Arthritis and Allied Conditions, 14th edn (ed. W.J. Koopman), Wiliams Wilkins, pp. 226-284. 

Sophia Fox, A.J., Bedi, A., Rodeo, S.A., 2009. The basic science of articular cartilage structure, composition, and function. Sports Health 1, 461—468. 

Bhosale, A.M., Richardson, J.B., 2008. Articular cartilage structure, injuries and review of management. British Medical Bulletin 87 (1), 77-95. 

Watanabe, H., Y. Yamada, and K. Kimata. 1998. Roles of aggrecan, a large chondroitin sulfate proteoglycan, in cartilage structure and function. J. Biochem. 124 687-693. 

FIGURE 9.34 Hyaluronate (see Figure 7.33) forms the backbone of proteoglycan structures, such as those found in cartilage. 

Collagen, the principal fibrous protein in mammalian tissue, has a tertiary structure made up of twisted a-helices. Three polypeptide chains, each of which is a left-handed helix, are twisted into a right-handed super helix to form an extremely strong tertiary structure. It has remarkable tensile strength, which makes it important in the structure of bones, tendons, teeth, and cartilage. 

Boskey A (2006) Mineralization, Structure and Function of Bone. In Dynamics of Bone and Cartilage Metabolism, 2nd edn. Seibel MJ, Robins SP, Bilezikian JP (eds), San Diego, Academic Press,201-212... 

RA is a chronic systemic disease that produces inflammatory changes throughout the connective tissue in the body. It affects joints and other organ systems of the body. Destruction of articular cartilage occurs, affecting joint structure and mobility. RA primarily affects individuals between 20 and 40 years of age. 

Chondroitin sulfates are located at sites of calcification in endochondral bone and are also found in cartilage. They are also located inside certain neurons and may provide an endoskeletal structure, helping to maintain their shape. 

The musculoskeletal system consists of bones, blood vessels, nerves, ligaments, tendons, muscles, and cartilage, which work together to perform the structural and kinematic functions of the organism. These musculoskeletal tissues all have a composite structure of cells embedded in a matrix produced by the cells themselves. 

Hydropolymer gel has been considered as a possible candidate for an artificial articular cartilage in artificial joints because it exhibits very low friction when it is in contact with a solid. The origin of such low friction is considered to be associated with the water absorbed in the gel [83-86], some of which is squeezed out from the gel under the load and serves as a lubricant layer between the gel and solid surface, resulting in hydrodynamic lubrication [87, 88]. Although the structural information about the interfacial water is important to understand the role of water for the low frictional properties of hydrogel in contact with a solid and the molecular structure of lubricants other than water at solid/solid interfaces have been investigated theoretically [89-91] and experimentally [92-98], no experimental investigations on water structure at gel/solid interfaces have been carried out due to the lack of an effective experimental technique. 

Hyaluronic acid and collagen are the two main structural components. The collagen is similar to that found in cartilage, consisting of three alpha-chains and known as type II collagen, although subtle differences are now recognized (Swann and Constable, 1972 Swann, 1980). 

---