BONE:
  • Bone is one of the hardest tissues in the body. The hardness of the bone, its ability to resist compression, is due to the inorganic calcium phosphate (calcium hydroxyapatite) deposited within the matrix. Numerous collagen fibers embedded within the matrix give the bone its ability to resist twisting and stretching.
  • The mature bone cells are called osteocytes. They are connected together by very fine tentacle-like cytoplasmic processes. Osteocytes lie within chambers in the matrix called lacunae. Radiating in all direction from the lacunae are minute canals called canaliculi. They connect the lacunae with each other. Canaliculi are filled with extracellular fluid and contain the slender cytoplasmic processes of the osteocytes.
  • There are two types of bone tissue:
    1. compact bone
    2. spongy bone