Tissue fluid

Just as Ambitious1999 has said, it essentially bathes the tissues, aiding the transfer of nutrients from the capillaries to the tissues and also aiding the removal of metabolic waste products, such as carbon dioxide, from the tissues to the blood. When blood enters the arteriolar end of the capillary, tissue fluid (essentially blood minus plasma proteins, red blood cells, white blood cells) is squeezed out of the capillary into the extracellular space surrounding the cells. Most of this tissue fluid is eventually reabsorbed at the venular end of the capillary (where the hydrostatic pressure is a bit lower and the oncotic pressure from the plasma proteins is a bit higher). However, a small amount remains and this is returned to the circulation via the lymphatic system.