Osteon is described as the essential building component of bone. Which of the following restates this description?

• A. The secretory unit of bone marrow
• B. The basic cellular unit of bone tissue
• C. The essential building component of bone
• D. The mineral deposit

Answer: (C)

The key idea here is recognizing the osteon as the fundamental structural unit of compact bone. An osteon, also called the Haversian system, is the repeating functional unit that makes up dense bone. It features concentric lamellae around a central Haversian canal with blood vessels and nerves, while osteocytes lie in lacunae connected by canaliculi to maintain the matrix. This organized unit is what gives cortical bone its strong, load-bearing framework, so describing the osteon as the essential building component of bone aligns with its role. The other options point to different concepts: bone marrow secretions relate to hematopoietic tissue, the basic cellular unit would refer to bone cells themselves rather than the tissue’s structural unit, and mineral deposits describe the inorganic crystals in bone, not the unit of tissue.