preview

Synovial Joints

Decent Essays

Synovial joints, also known as diarthroidal joints, are the most common and movable type in the body. The presence of lubricating synovial fluid encapsulated by joint ligaments distinguishes this type of joint from others within the body90. OA most commonly occurs within the weight bearing synovial joints including the hip and the knee, which is why obesity is such a major risk factor of OA4. The synovial joint can be broken down into four major components: articular cartilage, synovium, joint cavity filled with synovial fluid, and joint capsule ligament (Figure 1a) 60,115. Ultimately, articular cartilage and the synovial fluid are the main constituents that contribute to the proper lubrication properties of healthy and OA synovial joints.

3.1.1. Articular Cartilage …show more content…

Overall, articular cartilage is a very dense structure, lacking blood vessels and nerves that are found in other tissues77. Chondrocytes are the cell types embedded within cartilage, and produce the structural proteins that form the ECM. The major components of the ECM are water, type II collagens, proteoglycans, aggrecan, and noncollagenous proteins such as fibronectins115,22. The resulting osmotic pressure created within the wet and dry components of the ECM work in harmony to support the mechanical forces applied to cartilage77. The water is retained in the ECM by aggrecan, the primary structural proteoglycan which is based on a long hyaluronic acid backbone with highly charged glycosaminoglycan (GAG) side chains, such as chondroitin sulfate (CS) and keratin sulfate (KS)26. Altogether, these components are what create the depth dependent layers of cartilage: the superficial zone, the middle zone, the deep zone, and the calcified zone (Figure

Get Access