Physiology -Chap 6- Outline

The Skeletal System: Bone Tissue

Functions of Bone and The Skeletal System

• The functions of the skeletal system
  
  • Support: Framework for the body, supports soft tissues and provides attachment point for tendons of most skeletal muscles
    
  • Protection: Protect most important internal organs from injury
    
  • Assistance in Movement: Attach to bones; when the contract, they pull on bones to produce movement
    
  • Mineral Homeostasis: Bone tissue stores several minerals (calcium & phospherus)
    
  • Blood Cell Production: CT called red bone marrow produces more RBC, WBC, and platelets (called hemopoisis
    
  • Triglyceride Storage: Yellow bone marrow consists of adipose cells which store Trigly. The stored Trygly. Are a potential chemical energy reserve
    

    
    

  Structure of the Bone
  

• Lone bone=Greater length than width
  
• Long bone consists of:
  
  • Diaphysis
    
  • Epiphyses
    
  • Metaphyses
    
  • Epiphyseal Plate
    
  • Articular Cartalidge
    
  • Periosteum
    
  • Medullary Caivity
    

    
    

  
  

  Histology of Bone Tissue
  

• Bone tissue contains EC-M
  
  • 25% water, 25% Collagen fibers, 50% crystallized mineral salts.
    
    • Calcium phosphate + calcium hydroxide = hydroxyapatite
      
      • Califacation started by bone building cells
        
        • Process requires presences of collagen fibers
          
• Hardness = crystallized minerals
  
• Flexibility = collagen fibers
  
  • Provide tensile, strength, and resistance
    
• Four cells in tissue:
  
  • Osteogenic Cells: Unspecialized stem cells derived from mesenchyme, the tissue from which all CT are made from
    
  • Osteoblasts: Bone building cells. Synthesizes and secrete collagen
    
  • Osteocytes: Mature bone cells are the main cells in bone tissueand maintain it's daily metabolism
    
  • Osteoclasts: Cells derived from fusion of as many as 50 monocytes and are concentrated in the endosteum
    

    
    

  Compact Bone Tissue
  

• Compact bone tissue contains few spaces
  
• Strongest form of BT
  
• Found beneath periosteum, makes up bulk of long bones
  
• Blood vessels, lymthpatic vessels, ect. Transverse perforating canals
  
• Central canals
  
  • Around those are the concentric lamellae
    
  • Between lamellae are the lacunae
    
    • Tiny canaliculi filled with EC fluid
      
• Components of compact bone tissue are arranged into repeating units calls osteons or haversian systems
  
  • Parallel in shaft
    
    • Does not bend or fracture
      
    • Lines of stress change as baby starts to walk
      
• Area between osteans contain interstitial lamellae
  

  
  

  Spongy Bone Tissue
  

• No osteons
  
• Refers to appearance
  
• Consists of lamellae arranged in lattice of thin columns called trabeculae
  
  • Lacunae contain osteocytes
    
• Spongy bone tissue make up most of bone tissue of short flat, and irregularly shaped bones
  

  
  

  
  

  VOCAB:
  

  
  

  Diaphysis:Shaft of bone; long cylindrical main portion
  

  Epiphyses: Distal and proximal ends of bone
  

  Metaphyses: Regions in mature bone where the diaphysis join the epiphyses. Each meta. Includes an
  

  
  

  Epiphyseal Plate: Layer of hyaline cartilage that allows diaphylsis of bone in great length
  

  Epiphyseal Line: The boney result of the cartilage in the epip. plate being replaced by bone, caused by the stop of growth of the bone
  

  Articular Cartalidge Thin layer of hyaline cartilage covering epip. where the bone forms a joint with another bone
  

  Periosteum: Tough sheath of dense irregular CT that surrounds the done surface, enable bones to grow in thickness, not length. Aids in healing of bone
  

  Medullary Caivity: space within the diaphysis that contains fatty yellow bone marrow in adults
  

  Endosteum: Thin membrane that lines the medullary cavity. Contain single layer of bone forming cells and a small amount of CT
  

  Bone/Osseous Tissue: CT, contains abundant EC-M
  

  Hydroxyapatite: Calcium phosphate + calcium hydroxide
  

  Califacation:
  Process of minerals combining to form other minerals
  

  
  

epiphyseal plate