What are the hollow tubes of bone matrix whose collagen fibers are arranged in alternating directions in adjacent rings?

What are the hollow tubes of bone matrix whose collagen fibers are arranged in alternating directions in adjacent rings?

• A. Central canals
• B. Lamellae
• C. Perforating canals
• D. Lacunae

Answer: (B)

The structure described are lamellae, the concentric rings of bone matrix that surround the central canal in an osteon. Each lamella has collagen fibers aligned in one direction, but the direction rotates in adjacent rings, so the fibers in neighboring layers run in alternating directions. This arrangement gives the bone tensor-like strength, helping it resist twisting forces. Central canals are hollow channels running through the middle of an osteon for blood vessels and nerves; perforating canals connect these canals between osteons; lacunae are small spaces within the matrix that house osteocytes.

The structure described are lamellae, the concentric rings of bone matrix that surround the central canal in an osteon. Each lamella has collagen fibers aligned in one direction, but the direction rotates in adjacent rings, so the fibers in neighboring layers run in alternating directions. This arrangement gives the bone tensor-like strength, helping it resist twisting forces. Central canals are hollow channels running through the middle of an osteon for blood vessels and nerves; perforating canals connect these canals between osteons; lacunae are small spaces within the matrix that house osteocytes.