American Board of Surgery Qualifying Exam (ABS QE) Practice Test

During which phase of wound healing do fibroblasts and collagen appear?

1. Inflammatory phase

2. Proliferatory phase

3. Remodeling phase

4. Granulation phase

The correct answer is: Proliferatory phase

The proliferatory phase of wound healing is characterized by the significant activity of fibroblasts and the formation of collagen. During this phase, which occurs after the inflammatory phase, fibroblasts migrate to the wound site and synthesize collagen, providing structural support for the healing tissue. This collagen deposition is critical for the tensile strength and overall integrity of the newly formed tissue. Granulation tissue, which is also formed during the proliferatory phase, contains new capillaries, macrophages, fibroblasts, and collagen, all of which work together to fill in the wound and promote healing. As the proliferatory phase progresses, the wound begins to close as epithelial cells migrate across the surface of the granulation tissue, further aided by the increased collagen matrix that provides support for the growing tissue. In contrast, the inflammatory phase occurs first and involves processes such as hemostasis and the infiltration of inflammatory cells to clean the wound, which does not focus on fibroblast activity. The remodeling phase, which comes after proliferation, focuses on collagen maturation and reorganization but does not predominantly feature newly appearing fibroblasts and collagen synthesis as the proliferatory phase does.