Lymph: Transports tissue fluid, proteins, fats, and other materials from the tissues to the circulatory system. This occurs through a series of tubes called the lymphatic vessels. Lymph is a fluid made up of water, glucose, protein, fats, and salt. The cellular components are lymphocytes and granulocytes. They flow in tubes called lymphatic vessels, which closely parallel the veins and bathe the tissue spaces between cells.