Synovial fluid may be collected by syringe in a procedure termed arthrocentesis, also known as joint aspiration. It also contains phagocytic cells that remove microbes and the debris that results from normal wear and tear in the joint.Ĭlinical significance Collection There also is some evidence that it helps regulate synovial cell growth. Chiefly, it is responsible for so-called boundary-layer lubrication, which reduces friction between opposing surfaces of cartilage. Synovial fluid contains lubricin (also known as PRG4) as a second lubricating component, secreted by synovial fibroblasts. Hyaluronan is synthesized by the synovial membrane and secreted into the joint cavity to increase the viscosity and elasticity of articular cartilages and to lubricate the surfaces between synovium and cartilage. Normal synovial fluid contains 3–4 mg/ml hyaluronan (hyaluronic acid), a polymer of disaccharides composed of D-glucuronic acid and D-N-acetyl glucosamine joined by alternating beta-1,4 and beta-1,3 glycosidic bonds. Synovial fluid has thixotropic characteristics under conditions of sudden increase in pressure as in some kind of mechanical shock, its viscosity suddenly increases. Synovial fluid exhibits non-Newtonian flow characteristics the viscosity coefficient is not a constant and the fluid is not linearly viscous. Synovial fluid is made of hyaluronic acid and lubricin, proteinases, and collagenases. Two cell types (type A and type B) are present: Type A is derived from blood monocytes, and it removes the wear-and-tear debris from the synovial fluid. Synovial tissue is sterile (meaning microorganisms are not typically found there ) and composed of vascularized connective tissue that lacks a basement membrane. This function is dependent on the molecular weight of the hyaluronan. molecular sieving - pressure within the joint forces hyaluronan in the fluid against the synovial membrane forming a barrier against cells migrating into, or fluid migrating out of, the joint space.nutrient and waste transportation - the fluid supplies oxygen and nutrients and removes carbon dioxide and metabolic wastes from the chondrocytes in the surrounding cartilage.shock absorption - as a dilatant fluid, that possesses rheopectic properties, becoming more viscous under applied pressure the synovial fluid in diarthrotic joints becomes thick the moment shear is applied in order to protect the joint and subsequently, thins to normal viscosity instantaneously to resume its lubricating function between shocks.
reduction of friction - synovial fluid lubricates the articulating joints.The functions of the synovial fluid include: During movement, the synovial fluid held in the cartilage is squeezed out mechanically to maintain a layer of fluid on the cartilage surface (so-called weeping lubrication). The fluid in articular cartilage effectively serves as a synovial fluid reserve. This fluid forms a thin layer (roughly 50 μm) at the surface of cartilage and also seeps into microcavities and irregularities in the articular cartilage surface, filling all empty space. The fluid contains hyaluronan secreted by fibroblast-like cells in the synovial membrane, lubricin (proteoglycan 4 PRG4) secreted by the surface chondrocytes of the articular cartilage and interstitial fluid filtered from the blood plasma. Produced by cells within the joint tissues. Synovial fluid is an ultrafiltrate from plasma, and contains proteins derived from the blood plasma and proteins that are The inner membrane of synovial joints is called the synovial membrane and secretes synovial fluid into the joint cavity. Synovial fluid is a small component of the transcellular fluid component of extracellular fluid. With its egg white–like consistency, the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement. Synovial fluid, also called synovia, is a viscous, non-Newtonian fluid found in the cavities of synovial joints.
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