A first-year medical student undergoes a surgical procedure involving a midline laporotomy incision. The patient presents back to the surgeon approximately 3 months later and asks the surgeon: “What type of tissue is causing the scar to form on my abdomen?” The physician promptly answers:
1.Keratin
2.Type 1 collagen
3.Type 2 collagen
4.Type 3 collagen
5.Type 4 collagen
solution
Type 1 collagen is the most abundant collagen type found within the human body. Type 1 collagen is a primary component in scar formation.
Type 1 collagen is an important constituent of many different tissue types including: dermis, bone, tendons, ligaments, blood vessels, and scar tissue. Genetic mutations in type 1 collagen can lead to disease such as osteogenesis imperfecta. Collagen takes on a triple helix structure after significant chemical modification inside and outside of the cytosol. Vitamin C deficiency or scurvy results in the production of defective collagen and thus the inability to generate many of the tissue types that are essential for normal functioning.
Uusimaa et al. studied scar formation after acute myocardial infarction. They found that changing levels of both type I and type III collagen were indicative of an evolving scar on the myocardium. Scar formation was most prominent during the largest cases of myocardial infarction.
Haukipuro et al. studied the evolution of collagen peptides at the site of wound healing. They tested fluid from a a healing surgical wound for 7 days postoperatively. They found increasing levels of precursor collagen peptides throughout this initial period of wound healing.
Illustration A is a figure depicting the tertiary structure of a collagen helix.