1. Cerebrospinal fluid: This is the fluid that surrounds and protects the brain and spinal cord. 2. Synovial fluid: Found in the joints, synovial fluid helps to lubricate and cushion the joints during movement. 3. Pericardial fluid: This fluid is found in the pericardial sac surrounding the heart and helps to reduce friction during heartbeats. 4. Pleural fluid: Found in the pleural cavity surrounding the lungs, pleural fluid helps to lubricate the lungs and chest wall during breathing. 5. Peritoneal fluid: This fluid is found in the peritoneal cavity, which surrounds the abdominal organs, and helps to lubricate and protect them.