Which type of collagen is primarily found in hyaline cartilage?

• A. Type III
• B. Type II
• C. Type I
• D. Type V

Answer: (B)

In hyaline cartilage, the extracellular matrix is built primarily from type II collagen. This fibrillar collagen forms thin, lightweight fibrils that create a supportive network, providing the tensile strength and shape needed for cartilage to resist compressive and shearing forces in joints. The matrix also contains proteoglycans like aggrecan, which trap water and generate swelling pressure; the type II collagen fibrils resist that expansion and help distribute loads evenly.

Other collagens are more characteristic of different tissues: type I is dominant in bone, skin, and tendon; type III is common in reticular fibers of various tissues; type V is found in places like placenta and certain connective tissues. Cartilage specifically relies on type II as its main structural collagen, often with associated collagens like type IX and XI that modify and stabilize the type II fibrils.