LM of fibroblasts. A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. Fibroblasts are flat, elongated, undifferentiated cells in connective tissue that give rise to various precursor cells that form the fibrous, binding, and supporting tissue of the body. Fibroblasts can become chondroblasts, collagenoblasts, or osteoblasts. Magnification 133x.