There exist many empty spaces or cavities between the tissues of a human body, these cavities are known as the interstitial space; and in this space, many fluids flow in order to protect the cells from any harmful substance that might enter these spaces, these fluids are what known as the Interstitial fluids, an example of it would be the Lymph. These fluids lubricate and surround the tissues to protect them from any harmful substance. They also facilitate the transfer of nutrients from the blood to the cells they surround.