Final answer:
Fibroblasts are the primary cells in supporting connective tissue that help to develop and maintain the extracellular matrix, supporting other cells within the tissue.
Step-by-step explanation:
The fibroblasts are the cells of the supporting connective tissue, which provide the environment for the development of other cells within the tissue. These cells originate in the mesodermal germ layer and differentiate from mesenchyme and hematopoietic tissue in the bone marrow. Fibroblasts are the most prevalent in connective tissue, producing and secreting polysaccharides and proteins that combine with extracellular fluids to create the viscous ground substance. This substance, along with embedded fibrous proteins, forms the extracellular matrix that provides support to the surrounding cells. Fibrocytes, adipocytes, and mesenchymal cells are considered fixed cells within the connective tissue proper, while other cells such as macrophages and lymphocytes are part of the immune system and migrate in and out in response to chemical signals.