In the fibrosis cycle, what occurs after vascular support system increases?

• A. Increased collagen synthesis
• B. Myofibroblast infiltration and activation
• C. Fibroblast infiltration and activation
• D. Impeded movement

Answer: (C)

When the vascular support system increases, the tissue is being prepared to heal, and blood supply brings in the signals that recruit repair cells. Angiogenesis not only delivers nutrients but also attracts fibroblasts from the surrounding tissue and circulating precursors into the injury site. These fibroblasts then become activated, proliferate, and begin producing extracellular matrix components like collagen, laying down the scaffold that leads to scar formation. Some of the activated fibroblasts can differentiate into myofibroblasts later on, aiding contraction and continued matrix production, but the immediate next step after the rise in vascular supply is fibroblast infiltration and activation. This is why the option describing fibroblast infiltration and activation best fits the sequence. Impeded movement would contradict the active repair process, and focusing on myofibroblasts alone emphasizes a later specialization within the same activation process.