Microscopic Marvels: Understanding Compact and Spongy Bone Structures

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Compact bone, also known as cortical bone, forms the dense outer layer of bones. It provides strength, support, and protection. Microscopically, compact bone is composed of repeating units called osteons or Haversian systems. Each osteon consists of concentric layers of bone tissue known as lamellae, which surround a central canal containing blood vessels and nerves. The osteocytes, or mature bone cells, reside within small spaces called lacunae, located between the lamellae. Tiny channels called canaliculi connect the lacunae and allow for nutrient exchange and cell communication. Compact bone is highly organized and tightly packed, giving it a solid appearance.