Medicine & USMLE


  1. Osteoblasts
  2. Osteoclasts
  3. Osteocytes
  4. Spongy Bone
  5. Compact Bone
  6. Bone Structure
  7. Cartilage
  8. Joints
  9. Type 1 vs. Type 2 Muscle Fibers


Osteoclasts are a type of cell that breaks down bone tissue, releasing its components into our bloodstream. In doing this, osteoclasts release calcium back into the bloodstream, thereby increasing calcium levels.

Key Points

  • Osteoclasts
    • Osteoprogenitor cells
      • Differentiate into osteoblasts 
    • Resorb bone matrix 
      • Release proteolytic enzymes and acid that breaks down bone mineralization and the osteoid matrix
      • OsteoClasts Consume bone 
      • Reduce bone density
    • Release calcium into blood
    • Develop from monocytes