Tissues and Organs of the Skeletal System (pp.226-228)

1. Dynamic nature of bone
   
2. Organs of the skeletal system
   
3. Functions of the skeleton (table 8.1)
   
4. Bones and osseous tissue
   
5. Bones of the skeletal system
   a.  Number of bones
   b.  Changes and variations in number
   c.  Subdivisions of the skeleton
   
   • Axial
   • Appendicular
   d.  Catalog of bones (table 8.2)
   

Gross Anatomy of Bones (pp.228-232)

1. Shapes and examples
   a.  Long (femur, humerus)
   b.  Short (carpals, tarsals)
   c.  Flat (cranium, sternum)
   d.  Irregular (vertebrae, facial bones)
   
2. General features of bones
   a.  Dense and spongy bone
   b.  Medullary cavity
   c.  Diaphysis and epiphysis
   d.  Articular cartilage
   e.  Nutrient foramina
   f.  Periosteum and endosteum
   g.  Epiphyseal plate and line
   
3. Elaborations of bone structure (table 8.3)
   

Histology of Osseous Tissue (pp.232-236)

1. The cells of osseous tissue
   a.  Osteogenic cells
   b.  Osteoblasts
   c.  Osteocytes
   d.  Osteoclasts
   
2. The matrix of osseous tissue
   a.  Organic components
   
   • Collagen
   • GAGs, proteoglycans, and glycoproteins
   b.  Mineral component
   
   • Hydroxyapatite (85%)
   • Calcium carbonate (10%)
   • Cations: Mg²⁺, Na⁺, K⁺
   • Anions: F^-, SO₄^2-, CO₃^2-, OH^-
   c.  Combination of strength and resilience
   
3. Histology of compact bone
   a.  Haversian canal and lamellae
   b.  Lacunae and canaliculi
   c.  Nutrient canals
   
4. Histology of spongy bone
   a.  Trabeculae
   b.  Strength with minimal weight
   
5. Bone marrow
   a.  Red marrow (myeloid tissue)
   b.  Yellow marrow
   c.  Gelatinous marrow
   d.  Changes in distribution with age
   

Bone Development (pp.236-240)

1. Intramembranous ossification
   a.  Condensation of mesenchyme
   b.  Differentiation of osteoblasts
   c.  Deposition of osteoid tissue
   d.  Cell entrapment in lacunae
   e.  Formation of spongy bone trabeculae
   
2. Endochondral ossification
   a.  Primary ossification center
   
   • Chondrocyte hypertrophy
   • Formation of bony collar
   • Vascular buds
   • Creation of primary marrow space
   • Deposition of osteoid tissue
   • Mineralization
   b.  Metaphysis
   
   • Zone of reserve cartilage
   • Zone of cell proliferation
   • Zone of cell hypertrophy
   • Zone of calcification
   • Zone of bone deposition
   c.  Secondary ossification center
   
3. Bone growth and remodeling
   a.  Changes in size and contour
   b.  Development of surface processes
   c.  Increase in width
   
   • Appositional growth on outside
   • Erosion on medullary side
   d.  Closure of epiphyseal plates
   

Physiology of Osseous Tissue (pp.240-244)

1. Mineral deposition
   a.  Collagen as a prerequisite
   b.  Formation of seed crystals
   c.  Importance of solubility product
   
2. Mineral resorption
   a.  Hydrogen ion pumps of osteoclasts
   b.  Role of acid phosphatase
   
3. Calcium and phosphorus homeostasis
   a.  Uses of calcium and phosphate ions
   b.  Importance of blood calcium levels
   
   • Effects of hypocalcemia
   • Effects of hypercalcemia
   c.  Calcitonin (from thyroid)
   
   • Inhibits osteoclasts
   • Stimulates osteoblasts
   • Lowers plasma Ca²⁺ concentration in children
   • Negligible effect in adults
   d.  Parathyroid hormone (PTH)
   
   • Stimulates osteocytes and osteoclasts to resorb bone
   • Promotes renal phosphate excretion
   • Promotes renal calcium retention
   • Promotes vitamin D synthesis
   • Promotes intestinal absorption of calcium
   • Raises blood calcium levels
   e.  Vitamin D
   
   • Synthesis by skin, liver, and kidneys
   • Promotes intestinal absorption of calcium and phosphate ions
   • Reduces urinary excretion of both
   • Causes bone deposition
   f.  Other hormones and growth factors affecting bone
   
   • Sex steroids
   • Insulin, thyroid hormone, growth hormone
   g.  Vitamins A and C
   

Bone Disorders (pp.244-247)

1. Bone diseases (table 8.6)
   
2. Fractures and their repair
   a.  Classification (table 8.6)
   b.  The healing of fractures
   
   • Fracture hematoma
   • Granulation tissue
   • Soft and bony callus
   • Remodeling
   c.  The treatment of fractures
   
   • Closed and open reduction
   • Orthopedics

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