Which fibers make up the organization of lamellae in bone?

• A. Collagen
• B. Elastin
• C. Myosin
• D. Keratin

Answer: (A)

Lamellae in bone are organized by collagen fibers, primarily type I collagen. Within each lamella, collagen fibers run in a relatively uniform orientation, and successive lamellae rotate their fiber direction by about 90 degrees. This alternating arrangement creates a strong, resilient scaffold that resists bending and torsion and provides the framework for mineral deposition that hardens the bone. Other proteins listed don’t form this organized, mineralized lamellar structure—elastin supports elasticity in other tissues, keratin is found in hair and nails, and myosin is a muscle protein. So collagen is the fiber that organizes the lamellae in bone.