The ground substance is made up of four major things: water, Proteoglycans, Glycoproteins and Water. It creates the fluid-rich environment that all the components of connective tissue sit within. The fixed cells are those which can't really move out and around or so forth. They still come from the mesoclimal cells, and that still gives them the capacity to regenerate that population. But then you have the fixed cells that are actually locked in the tissue. That's going to be all the resident cells.