A brief about Bone
Bone
A dynamic form of specialized connective tissue. Cells - 10 % ; Extracellular matrix (ECM)- 90 %.
Cells - 1. Osteoblasts , Osteocytes, Osteoclasts
ECM -- 1. Organic - type I collagen
2. Inorganic - Calcium Phosphate, Osteocalcium Phosphate.
Functions
1. movement
2. support and protect internal organs
3. produces RBCs/ WBCs
4. storage for calcium and phosphte
Difference
Osteoblasts
- derived from undifferentiated mesenchymal cells
- bone forming ,lay down Osteoid (type I collagen)
- contains RANK (receptor activator for nuclear factor kappa
Osteoclasts
- monocyte lineage multinucleated giant cells that resorb bone
- location - small pits called Lacunae,bone surfaces and lead cutting cones.
- ruffled brush border ,increase surface area ,create low ph to dissolve inorganic compounds
- Enzymes release - Tartarate resistant acid phosphatase and proteases
- breaks down organic matrix components
- inhibits Osteoprotegrin.
Osteocytes
- Osteocytes that have become trapped in bone matrix
- 90 % of cells in bone, important role in homeostasis of Ca and Phosphate
Wolff's Law
German Anatomist/Surgeon Jullius Wolff .
If loading on bone increases , bone remodel itself over time to become stronger to resist load.
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