Articular cartilage lacks blood and lymphatic vessels and its supply of nutrients diffuses from the synovial fluid into the cartilage matrix through pores that restrict large substances from crossing over. This lack of direct nutrients is also the reason why articulate cartilage uses anaerobic metabolism, according to a 2009 article in Sports Health.
Chondrocytes are the principal cells in articular cartilage and are formed from mesenchymal stem cells. They are suspended in their own matrix and are responsible for the regeneration and maintenance within their own microenvironment. Their poor ability to replicate explains the low healing capacity of articular cartilage, notes Sports Health.
Articular cartilage is composed of 80 percent water by weight. About 30 percent of this water is distributed in the intrafibrillar space and the rest is contained within the pores of the matrix. The distribution of water in these areas is considered one of the major reasons articular cartilage is able to withstand heavy loads. Additionally, water is a major contributor to nutrient transport between the synovium and the extracellular matrix, as well as dissolving inorganic ions, according to Sports Health. Collagen is the most abundant solid material and composes 65 percent of articular cartilage by dry weight. Proteoglycans are the second largest group of macromolecules and compose 10 to 15 percent of the weight.