The bones at a synovial joint are covered by a membrane of hyaline cartilage. This cartilage, also known as articular cartilage serves a function as shock-absorber and also, along with the secretion of synovial fluid in the membrane, helps reduce friction.he synovial membrane secretes synovial fluid that lubricates the articular surfaces of the joint. In some joints, the synovial membrane extends outside the joint capsule to form a bursa.