What is the purpose of synovial fluid?

Synovial fluid plays a key role in joint health and function, primarily by providing lubrication to the joints. This fluid is found in synovial joints, such as the knees, elbows, and shoulders, where it fills the joint capsule and ensures that the surfaces of the bones glide smoothly against each other during movement. The lubrication reduces friction and helps to prevent wear and tear on the cartilage, contributing to overall joint mobility and reducing the risk of injury. Additionally, synovial fluid also contains nutrients and enzymes that help maintain the health of the articular cartilage, further emphasizing its importance in joint maintenance and function.

The other options, while related to different systems in the body, do not accurately describe the primary function of synovial fluid. Bone cells are nourished by different mechanisms involving blood supply, muscle structure typically comes from connective tissues rather than a fluid, and nerve signal transmission involves neurotransmitters rather than synovial fluid.