CLT Wound Healing & Tissue Repair 1 — Questions and Answers
Question 1: What are the four primary phases of wound healing in the correct sequential order?
- Inflammation, proliferation, remodeling, hemostasis
- Hemostasis, inflammation, proliferation, remodeling (Correct answer)
- Proliferation, hemostasis, inflammation, remodeling
- Remodeling, proliferation, hemostasis, inflammation
Correct answer: Hemostasis, inflammation, proliferation, remodeling
Wound healing occurs in four sequential phases: hemostasis (clotting), inflammation (immune response), proliferation (tissue building), and remodeling (scar maturation).
Question 2: Which photoacceptor in cells is primarily responsible for absorbing red and near-infrared light to promote wound healing?
- Melanin
- Hemoglobin
- Cytochrome c oxidase (Correct answer)
- Rhodopsin
Correct answer: Cytochrome c oxidase
Cytochrome c oxidase in the mitochondrial respiratory chain is the primary photoacceptor for red and near-infrared light, triggering increased ATP production that supports wound healing.
Question 3: During which phase of wound healing does collagen synthesis by fibroblasts primarily occur?
- Hemostasis phase
- Inflammatory phase
- Proliferative phase (Correct answer)
- Maturation phase
Correct answer: Proliferative phase
The proliferative phase is characterized by fibroblast activity, collagen synthesis, angiogenesis, and granulation tissue formation to fill the wound.
Question 4: What wavelength range is most commonly used in photobiomodulation for promoting wound healing?
- 200–280 nm (UVC)
- 315–400 nm (UVA)
- 600–1100 nm (red to near-infrared) (Correct answer)
- 1200–2000 nm (mid-infrared)
Correct answer: 600–1100 nm (red to near-infrared)
The therapeutic window of 600–1100 nm (red to near-infrared) is most effective for wound healing because these wavelengths penetrate tissue and stimulate cellular repair mechanisms.
Question 5: Which growth factor, upregulated by light therapy, plays a key role in angiogenesis during wound healing?
- Tumor necrosis factor-alpha (TNF-α)
- Vascular endothelial growth factor (VEGF) (Correct answer)
- Interleukin-6 (IL-6)
- C-reactive protein (CRP)
Correct answer: Vascular endothelial growth factor (VEGF)
VEGF is a primary mediator of angiogenesis (new blood vessel formation), and photobiomodulation has been shown to upregulate VEGF expression, enhancing blood supply to healing wounds.
Question 6: Chronic wounds are often characterized by which of the following?
- Elevated fibroblast activity and excess collagen
- Accelerated progression through healing phases
- Prolonged inflammatory phase and impaired proliferation (Correct answer)
- Rapid epithelialization with minimal scarring
Correct answer: Prolonged inflammatory phase and impaired proliferation
Chronic wounds are stuck in a prolonged inflammatory phase with elevated proteases, impaired fibroblast function, and failure to progress to the proliferative phase.
Question 7: How does photobiomodulation reduce inflammation in early wound healing without completely suppressing the immune response?
- By destroying inflammatory cytokines with UV radiation
- By modulating reactive oxygen species and promoting anti-inflammatory mediators (Correct answer)
- By applying thermal energy to cauterize inflamed tissue
- By blocking pain receptors in the wound bed
Correct answer: By modulating reactive oxygen species and promoting anti-inflammatory mediators
Photobiomodulation modulates ROS levels and promotes anti-inflammatory mediators like IL-10, reducing excessive inflammation while preserving the necessary immune response for healing.
CLT Wound Healing & Tissue Repair 1
What are the four primary phases of wound healing in the correct sequential order?