Lymphatic vessels are small tubes that form a network throughout the body. They play an important role in maintaining fluid balance and filtering out waste products from tissues. These vessels carry lymph, which is a clear fluid containing white blood cells, proteins, and other substances, away from the tissues and back towards the heart. Lymphatic vessels help to prevent the buildup of excess fluids in the body's tissues and also play an important role in immune response by transporting waste products and pathogens out of the tissues and into the bloodstream where they can be eliminated from the body.