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Anatomy & Physiology: Osseous System and Bone Biology

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Terms in this set (23)

  • What is skeletal cartilage composed of and what are its key features?
    Skeletal cartilage is molded cartilage tissue primarily made of water, making it highly resilient. It contains chondrocytes in lacunae within a jelly-like extracellular matrix and lacks blood vessels and nerves.
  • What is the function of the perichondrium?
    The perichondrium is a dense connective tissue layer surrounding cartilage that prevents outward expansion and contains blood vessels for nutrient delivery to the cartilage.
  • Name the three types of cartilage and a key characteristic of each.
    Hyaline cartilage: most abundant, contains collagen fibers only.
    Elastic cartilage: contains elastic fibers, found in external ear and epiglottis.
    Fibrocartilage: thick collagen fibers, great tensile strength, found in menisci and vertebral discs.
  • Describe appositional and interstitial growth of cartilage.
    Appositional growth: cartilage-forming cells in perichondrium secrete matrix on the external surface.
    Interstitial growth: chondrocytes within lacunae divide and secrete new matrix, expanding cartilage from within.
  • List the seven functions of bones.
    Support, protection, movement, mineral and growth factor storage, hematopoiesis, triglyceride storage, and hormone production.
  • What are the two main divisions of the human skeleton?
    Axial skeleton: skull, vertebral column, rib cage.
    Appendicular skeleton: upper and lower limbs and girdles attaching limbs to axial skeleton.
  • Classify bones by shape and give an example of each.
    Long bones: longer than wide, e.g., femur.
    Short bones: cube-shaped, e.g., carpals.
    Flat bones: thin and flat, e.g., sternum.
    Irregular bones: complicated shapes, e.g., vertebrae.
  • Why are bones considered organs?
    Bones contain multiple tissue types including osseous tissue, nervous tissue, cartilage, fibrous connective tissue, muscle cells, and epithelial cells in blood vessels.
  • What are the two main types of bone tissue seen grossly?
    Compact bone: dense outer layer, smooth and solid.
    Spongy bone: honeycomb of trabeculae with spaces filled by red or yellow marrow.
  • What is the periosteum and its layers?
    The periosteum is a double-layered membrane covering bone surfaces except joints.
    Fibrous layer: dense irregular connective tissue.
    Osteogenic layer: contains osteogenic stem cells and nutrient foramina.
  • Name the five types of bone cells and their primary functions.
    Osteogenic cells: stem cells that differentiate into osteoblasts.
    Osteoblasts: bone-forming cells secreting osteoid.
    Osteocytes: mature bone cells maintaining matrix.
    Bone-lining cells: maintain matrix on bone surfaces.
    Osteoclasts: multinucleated cells that resorb bone.
  • What is an osteon and its components?
    An osteon is the structural unit of compact bone, consisting of concentric lamellae with collagen fibers, a central (Haversian) canal containing blood vessels and nerves, lacunae with osteocytes, and canaliculi connecting lacunae.
  • Describe the chemical composition of bone.
    Bone is composed of organic components (cells and osteoid with collagen fibers) providing tensile strength and flexibility, and inorganic mineral salts (hydroxyapatites) providing hardness and resistance to compression.
  • What is intramembranous ossification and where does it occur?
    Intramembranous ossification is bone formation directly from mesenchymal tissue, occurring in cranial bones and clavicles.
  • Outline the main steps of endochondral ossification.
    Bone forms by replacing hyaline cartilage: mesenchymal cells become osteoblasts, cartilage model forms, cartilage calcifies, periosteal bud invades, primary and secondary ossification centers form, and epiphyses ossify.
  • What are the five zones of the epiphyseal plate?
    Resting zone (inactive cartilage), proliferation zone (rapidly dividing cartilage), hypertrophic zone (enlarging chondrocytes), calcification zone (matrix calcifies, chondrocytes die), ossification zone (new bone forms).
  • How does bone remodeling occur?
    Bone remodeling involves coordinated resorption by osteoclasts and deposition by osteoblasts at periosteal and endosteal surfaces, regulated by mechanical signals and hormones.
  • What hormones regulate blood calcium levels via bone remodeling?
    Parathyroid hormone (PTH) increases blood calcium by stimulating osteoclasts; calcitonin lowers blood calcium at high doses; leptin and serotonin also influence bone density and turnover.
  • Explain Wolff's law in bone physiology.
    Wolff's law states that bones grow or remodel in response to mechanical stresses placed on them, adapting their shape and strength accordingly.
  • Name and describe three common types of bone fractures.
    Comminuted: bone breaks into three or more pieces.
    Spiral: ragged break from twisting forces.
    Greenstick: incomplete break, common in children.
  • What are the four stages of fracture repair?
    Hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling.
  • What is osteoporosis?
    A group of diseases where bone resorption exceeds deposition, leading to decreased bone mass and increased fracture risk.
  • What causes rickets and what are its effects?
    Rickets is caused by vitamin D deficiency or insufficient calcium, leading to poorly mineralized bones, bowed legs, and bone deformities in children.