Which of the following is/are true concerning wound fibroblasts?

A. Fibroblasts synthesize and secrete collagen molecules.

C. Fibroblasts migrate to a wound along fibrin strands, which are used as a scaffold.

D. Large amounts of fibrin or blood clot can act as a physical barrier to fibroblast penetration, which delays normal wound healing.

DISCUSSION: Fibroblasts appear in the wound on about the third day of healing and begin to synthesize and secrete collagen molecules. Wound fibroblasts arrive from cells surrounding the wound (e.g., the adventitia of blood vessels), change their phenotype(s), and become mobile during the process of replication. Fibroblasts migrate into a wound using the provisional fibronectin and fibrin matrix as a scaffold. Fibroblasts do not have fibrinolytic enzymes, and large amounts of fibrin and blood clot prevent fibroblasts from entering the wound.