anaphy mine

• Functions of the skeletal system

  • Support
  • Protection
  • Assistance in Movement
  • Mineral Homeostasis (storage and release)
  • Blood Cell Production
  • Triglyceride Storage
• Support


  • Structural framework for body
  • Support soft tissues
  • Provide attachment points for tendons
• Protection


  • Protects most important internal organs from injury
• Assistance in Movement


  • Pull on bones to produce movement
• Mineral Homeostasis (storage and release)


  • Stores several minerals (calcium and phosphorus)
  • Bone releases minerals into the blood to maintain critical mineral balances (homeostasis)
  • Distribute minerals to other parts of the body
• Blood Cell Production

  • Hemopoiesis = process where red bone marrow produces rbc, wbc, and platelets
• Triglyceride Storage


  • Yellow bone marrow consists mainly of adipose cells, which store triglycerides
  • Stored triglycerides = potential chemical energy reserve
• Diaphysis


  • Bone's shaft or body
  • Long, cylindrical, main portion of the bone

  
• Epiphysis

  Proximal and distal ends of the bone

  
• Metaphyses


  Regions between diaphysis and epiphyses
• Articular Cartilage


  • Thin layer of hyaline cartilage
  • Covers the part of epiphysis where bone forms an articulation (joint) with another bone
  • Reduces friction and absorbs shock at freely movable joints
• Periosteum

  • Tough connective tissue sheath
  • Surrounds bone surface whenever it is not covered by articular cartilage
  • Protects bone, assists in fracture repair, nourish bone tissue, serve as attachment points

  
• Medullary Cavity


  • Hollow, cylindrical space within diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults
  • Minimizes weight of bone by reducing dense bony material
  • Long bones' tubular design provides maximum strenth with minimum weight
• Endosteum


  • Thin membrane that lines medullary cavity
  • Contains single layer of bone-forming cells and a small amont of connective tissue
• Osteoprogenitor Cells


  Unspecialized bone stem cells derived from mesenchyme = tissue from which connective tissues are formed

  
• Osteoblasts


  Bone building cells
• Osteocytes


  • Mature bone cells
  • Main cells in bone tissue and maintain its daily metabolism
  • Exchange of nutrients and wastes with the blood
• Osteoclasts


  • Huge cells derived from fusion of as many as 50 monocytes
  • Concentrated in the endosteum
• Compact Bone Tissue


  • Contains few spaces and is the strongest form of bone tissue
  • Found beneath the periosteum of all bones and makes up the bulk of the diaphyses of long bones

  
• Spongy Bone Tissue


  • Trabecular or cancellous bone tissue
  • Does not contain osteons
  • Located in the interior of a bone, protected by a covering of compact bone

  
• Periosteal Arteries


  • Small arteries accompanied by nerves
  • Enter diaphysis through many interosteonic (Volkmann's or perforating) canals
  • Supply the periosteum and outer part of the compact bone

  
• Nutrient Artery


  • Enters bone through nutrient foramen and branches into a number of smaller arteries and arterioles to supply maximum regions of adult bone
  • Sustains high blood pressure to reach distant locations, usually terminationg into capillaries present in the metaphysis and endosteum
• Metaphyseal Artery


  • Enter the metaphyses of a long bone and, together with the nutrient artery, supply the red bone marrow and bone tissue of the metaphyses

  
• Epiphyseal Arteries


  • Enter the epiphyses of a long bone and supply the red bone marrow and bone tissue of the epiphyses
• Fracture

  • Any break in a bone
  • Named according to their severity, shape, position of fracture line, or the physician who first described them

  
• Stress Fracture

  Series of microscopic fissures in bone that forms without any evidence of injury to other tissues

  
• Reactive Phase


  1. Early inflammatory phase

  2. Blood vessels crossing fracture line are broken

  3. Blood leaks from torn ends of vessels

  4. Fracture hematoma = mass of blood usually forms 6-8hrs after injury
• Reparative Phase: Fibrocartilaginous Callus Formation

  1. Blood vessels grow into fracture hematoma and phagocytes begin to clean up dead bone cells

  2. Fibrocartilaginous callus = mass of repair tissue consisting of collagen fibers and cartilage that bridges broken bone ends

  3. Formation takes about 3 weeks

  
• Reparative Phase: Bony Callus Formation

  1. Osteoprogenitor cells develop into osteaoblasts which begin to produce spongy bone trabeculae

  2. Bony callus lasts about 3-4 months

  
• Bone Remodeling Phase


  1. Dead portion of the original fragments of broken bone are gradually resorbed by osteoclasts

  2. Compact bone replaces spongy bone around the periphery of fracture

  
• Open (Compound) Fracture


  Broken ends of bone protrude through skin

  
• Closed (Simple) Fracture


  Does not break the skin
• Comminuted Fracture


  • Bone is splintered, crushed, or broken into pieces
  • Smaller bone fragments lie between two main fragments

  
• Greenstick Fracture


  • Partial fracture
  • One side of bone is broken and other side bends
• Impacted Fracture


  One end of fractured bone is forcefully driven into the other

  
• Pott Fracture


  Fracture of distand end of lateral leg bone (fibula)
• Colles Fracture


  Fracture of the distand of lateral forearm bone (radius)

  
• Adult Human


  Consists of 206 named bones
• Infants and Children

  • More than 206 bones
  • Some of their bones fuse later in life
• Axial Skeleton


  • 80 bones
  • Skull (8 cranium, 14 face, 1 hyoid bone, 6 auditory ossicles)
  • Vertebral column (26)
  • Thorax (1 sternum, 24 ribs)