The synovial membrane secretes a watery fluid that lubricates and cushions the joint.

The synovial membrane is a specialized connective tissue membrane that lines the inner surface of synovial joints. It is responsible for secreting synovial fluid, a clear and viscous liquid that lubricates and cushions the joint.

Structure and location of the synovial membrane:
- The synovial membrane consists of two main layers: an inner layer called the synovial intima and an outer layer called the synovial subintima.
- The synovial intima is composed of a single layer of specialized cells called synoviocytes. These cells are responsible for producing and maintaining synovial fluid.
- The synovial subintima is a loose connective tissue layer that contains blood vessels, nerves, and fibroblasts. It provides support and nutrition to the synovial membrane.

Function of synovial fluid:
- Synovial fluid plays a crucial role in joint function and health. It performs several important functions, including lubrication, nutrient supply, shock absorption, and waste removal.
- Lubrication: The synovial fluid acts as a lubricant, reducing friction between the articular surfaces of the joint during movement. This allows for smooth and painless joint motion.
- Nutrient supply: The synovial fluid delivers essential nutrients and oxygen to the articular cartilage, which lacks its own blood supply. This helps maintain the health and integrity of the cartilage.
- Shock absorption: The synovial fluid acts as a shock absorber, cushioning the joint and reducing the impact of mechanical forces. This helps protect the joint surfaces from damage.
- Waste removal: The synovial fluid also helps remove metabolic waste products and inflammatory mediators from the joint. It contributes to the overall cleanliness and homeostasis of the joint environment.

Conclusion:
The synovial membrane, found in synovial joints, secretes synovial fluid. This fluid lubricates the joint, reduces friction, supplies nutrients to the cartilage, absorbs shocks, and removes waste products. Its role in joint function and health is essential for smooth and pain-free movement.