Study Question Fifteen

• Q15. Describe the appearance and functions of the osteoblasts, osteocytes, osteoclasts.
• Osteoblasts are defined as cells that produce fibers and a matrix of bone within connective tissue or cartilage and they may differentiate into osteocytes
• Osteoclast are defined as a cell that dissolved the fibers and matrix of bone
• Osteocyte is defined as bone cells responsible for the maintenance of turnover of the mineral content of the surrounding bone
• Osteoblast appearance:

  • Cuboidal/columnar when active or flattened when less active
  • Single, centrally located nucleus
  • Basophilic due to rough endoplasmic reticulum and golgi apparatus
• Osteoblast function:

  • Secrete bone matrix components (mostly collagen)
  • Deposition of calcium phosphate crystals in matrix
  • Formation of new bone and repair
• Osteoclast appearance:

  • Large, irregular, multinucleated
  • Abundant with lysosomes and a ruffled border
• Osteoclast function:

  • Break down bone tissue by secreting acids and enzymes
  • Contribute to remodeling of bone by resorbing bone matrix
• Osteocyte appearance:

  • Rounded or star-shaped, embedded in lacunae within matrix
  • Single, centrally located nucleus
  • Long, canaliculi connecting to other osteocytes and bone surface
• Osteocyte functions:

  • Maintain matrix and respond to mechanical stresses
  • Nutrient and waste exchange between matrix and blood supply