Which tissues primarily contain Type I collagen?

• A. Hyaline cartilage
• B. Skin, Tendon, Bone
• C. Blood vessels, Parenchymal cells
• D. Basement membrane

Answer: (B)

Type I collagen forms thick, strong fibers that give tissues high tensile strength, making it the main collagen in tissues that bear mechanical loads. In the skin, it provides the sturdy support of the dermis; in tendons, it creates the robust connections that transmit muscle force to bone; and in bone, it forms the fibrous framework that supports mineralization and rigidity. Hyaline cartilage, by contrast, is rich in Type II collagen, which forms thinner fibrils suited to a smooth, resilient cartilage surface rather than high tensile strength. Basement membranes are primarily composed of Type IV collagen, forming a meshwork that underlies epithelial and endothelial cells. Blood vessel walls contain a mix of collagens, but are not dominated by Type I. So Skin, Tendon, and Bone are the tissues where Type I collagen is the principal type.