EVERYDAY SCIENCE

Detailed explanation-1: -Bursae: small fluid-filled sacs lined by a synovial membrane with an inner capillary layer of synovial fluid. It provides a cushion between bones and tendons and/or muscles around a joint. This helps to reduce friction between the bones and allows free movement.

Detailed explanation-2: -Synovial fluid is a viscous solution found in the cavities of synovial joints. The principal role of synovial fluid is to reduce friction between the articular cartilages of synovial joints during movement.

Detailed explanation-3: -Synovial joints are the only joints that have a space between the adjoining bones (Figure 19.25). This space is referred to as the synovial (or joint) cavity and is filled with synovial fluid. Synovial fluid lubricates the joint, reducing friction between the bones and allowing for greater movement.

Detailed explanation-4: -Synovial fluid is both a lubricant for joint surfaces (lubricin for boundary cartilage-to-cartilage lubrication and hyaluronate for synovium-on-synovium lubrication) and a source of nourishment for the avascular articular cartilage.

Detailed explanation-5: -The movement at a synovial joint is caused by the muscles attached across the joint. Muscles are attached to bone by tendons. Tendons are very strong, inelastic connective tissues that allow a muscle to pull on a bone to move it.