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Anatomy & Physiology: Bones and Bone Structure

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Terms in this set (23)

  • Major functions of the skeletal system
    Structural support, storage of minerals and lipids, blood cell production, protection of soft tissues and organs, and leverage for movement.
  • Classification of bones by shape
    Sutural, irregular, short, flat, long, and sesamoid bones, each with distinct shapes and locations.
  • Structure of a long bone
    Consists of a diaphysis (shaft of compact bone), epiphyses (ends of spongy bone), and metaphysis (zone connecting diaphysis and epiphysis).
  • Structure of a flat bone
    A core of spongy bone (diploë) between two layers of compact bone (cortex).
  • Bone tissue characteristics
    Dense matrix of protein fibers and calcium salts, with osteocytes in lacunae connected by canaliculi.
  • Bone matrix composition
    Two-thirds calcium phosphate (hydroxyapatite crystals) and one-third collagen fibers providing strength and flexibility.
  • Osteogenic cells
    Stem cells in periosteum and endosteum that divide and differentiate into osteoblasts, important for fracture repair.
  • Osteoblasts
    Immature bone cells that produce osteoid (organic matrix) and promote calcium salt deposition.
  • Osteocytes
    Mature bone cells in lacunae that maintain bone matrix and help repair damaged bone.
  • Osteoclasts
    Large multinucleate cells that resorb bone matrix by secreting acids and enzymes (osteolysis).
  • Osteon
    Basic functional unit of compact bone, consisting of a central canal surrounded by concentric lamellae and osteocytes in lacunae.
  • Types of lamellae in compact bone
    Concentric (form osteons), interstitial (fill spaces between osteons), and circumferential (outer and inner bone surfaces).
  • Spongy bone structure
    No osteons; matrix arranged as trabeculae with spaces filled by red or yellow bone marrow.
  • Periosteum
    Membrane covering bone surface with outer fibrous and inner cellular layers; isolates bone and aids growth and repair.
  • Endosteum
    Incomplete cellular layer lining inner bone surfaces, containing osteogenic cells, osteoblasts, and osteoclasts.
  • Endochondral ossification
    Process where bone replaces cartilage, forming most bones of the body.
  • Intramembranous ossification
    Bone formation within dermis producing flat bones like skull, mandible, and clavicles.
  • Bone growth types
    Interstitial growth increases length at epiphyseal plates; appositional growth increases width by adding circumferential lamellae.
  • Bone remodeling
    Continuous recycling of bone matrix involving osteocytes, osteoblasts, and osteoclasts to maintain bone strength and mineral balance.
  • Hormones regulating calcium homeostasis
    Parathyroid hormone increases blood calcium by stimulating osteoclasts; calcitonin decreases blood calcium by inhibiting osteoclasts.
  • Effects of exercise on bone
    Physical activity stimulates bone remodeling, making bones thicker and stronger; inactivity leads to bone mass loss.
  • Osteopenia and osteoporosis
    Osteopenia is reduced bone mass starting around age 30; osteoporosis is severe bone loss causing fragile bones.
  • Types of fractures
    Open (compound), closed (simple), transverse, displaced, compression, spiral, epiphyseal, comminuted, greenstick, Colles, and Pott's fractures.