What are the microscopic cells that compose bones called?

• A. Osteoblasts
• B. Osteocytes
• C. Osteoclasts
• D. Fibroblasts

Answer: (B)

Osteocytes are the microscopic cells that compose mature bone tissue. They originate from osteoblasts that become trapped in the bone matrix as it hardens, and they reside in small spaces called lacunae. Their long, branching processes extend through tiny canals (canaliculi) to communicate with each other and with surface-lining cells, allowing them to monitor and regulate mineral content and coordinate bone remodeling. Osteoblasts build new bone on surfaces, while osteoclasts resorb bone; fibroblasts produce connective tissue components rather than bone.