A 9-year-old boy receives a deep laceration over his right eyebrow playing ice hockey. The wound is cleaned and sutured Which of the following collagens is deposited first during wound healing in the patient.
High-Yield Explanation
Type III. Concurrent with fibrinolysis, a temporary matrix composed of proteoglycans, glycoproteins, and type III collagen is deposited. The secretion of type III collagen is a forerunner to the formation of type I collagen (choice A), which will impart greater tensile strength to the wound. TGF-b enhances the synthesis of collagen and fibronectin and decreases metalloproteinase transcription and matrix degradation. Extracellular cross-linking of newly synthesized collagen further increases the mechanical strength of the wound. Type II collagen (choice B) is found in cartilage. Type IV collagen (choice D) is found in basement membranes.Diagnosis: Laceration