Bone Tissue Mind Map PDF

Fracture→ callus formation for stabilisation→ **Fracture Repair** Remodeling of the bone reduced bone mass and increased bone...

Fracture→ callus formation for stabilisation→ **Fracture Repair** Remodeling of the bone reduced bone mass and increased bone **Osteoporosis** fragility, often leading to fractures caused by deficient mineralization of bone due to **Rickets (children) / Osteomalacia(adults)** vitamin D deficiency, resulting in soft, weak bones. **Bone Pathologies** Example: Robert Pershing Wadlow (Alton Giant) **Gigantism / Acromegaly** excess of growth hormones Example: Lucia Zarate **Hypophyseal Dwarfism** deficiency of growth hormone Connective tissue with solid extracellular matrix Example: Flat bones like the skull Mechanical support The direct formation of bones **Intramembranous Ossification** Functions Metabolic activity (like calcium storage) Mesenchyme differentiate→ Osteoblasts Hematopoietic (blood cell formation) secrete→ Matrix secretion (forming trabeculae) Steps: → Calcification Origin: Mesenchymal cells Example: Femur, vertebrae, ribs **Bone Ossification** Shape: Elongated with oval nuclei **Osteoprogenitors** This is the process by which most bones form, Most active during bone formation especially long bones Location: Periosteum + Endosteum Hyaline cartilage mode formed → Chondrocyte hypertrophy → Matrix calcifies → Invasion by Steps: **Endochondral Ossification** Origin: Osteoprogenitor cells osteoprogenitors → Osteoblast formation → Bone callus → Vascularization and calcification **Bone Tissue** Shape: Cuboidal or prismatic Reserve cartilage Bone Tissue Mind **Osteoblasts** Ovoid nucleus, basophilic cytoplasm when active Proliferative Map Secretes non-mineralized matrix: osteoid Hypertrophy **Zones** **Cells** (recent bone matrix none calsified) Calcified cartilage Origin: Osteoblasts Ossification **Osteocytes** Function: Bone matrix maintenance Elongated nucleus, cytoplasmic extensions for Outer surface of bone, surround the bone communication through junctions Dense irregular connective tissue, blood vessels Origin: share the same precursor as monocytes (MPS system) mononuclear phagocyte system (MPS) for supply **Periosteum** **Components** Large (20-100 µm), multinucleated, motile Osteogenic layer with osteoprogenitor cells **Osteoclasts** and osteoblasts Located in Howship lacunae (small depressions in bone) Sharpey fibers: very thick collagen fiber that work like anchors They have a Brush border for bone resorption Inner surface of bone, surround all the inner- Collagen fibers type I cavities of the bone (cancellous bone, medullary canal, Havers and Volkmann canals) **Organic Part** Ground substance (Glycosaminoglycans, Proteoglycans, Glycoproteins like osteonectin, Single layer of squamous cells (endosteal cells) **Endosteum** osteocalcin, osteopontin) **Extracellular Matrix** Osteogenic potential (can generate new bone primary mineral: Hydroxyapatite crystals form cells), so osteoproginators or osteoblasts of Calcium phosphate. (gives gone its hardness **Mineral Part** Dense bone matrix with lamellar structure Elements: Calcium, phosphorus, magnesium, **Bone Structure** sodium, potassium, etc. Osteon (Haversian system) Interstitial systems Components **Compact Bone** Circumferential systems (external and internal) Cylinders of concentric lamellae Havers canal **Haversian System** Volkmann canal Lamellar structure of fine trabeculae, (network-like) Irregularly arranged collagen fibers **Cancellous Bone** Haversian system rare Provides structural support while reducing bone weight