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Anatomy & Physiology: Bones and Skeletal Tissues

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Terms in this set (27)

  • What is skeletal cartilage primarily composed of?

    Skeletal cartilage is made of highly resilient cartilage tissue that consists primarily of water and contains no blood vessels or nerves.

  • What is the function of the perichondrium?

    The perichondrium is a dense connective tissue layer surrounding cartilage that helps resist outward expansion and contains blood vessels for nutrient delivery.

  • Name the three types of cartilage and a key feature of each.
    • Hyaline cartilage: most abundant, provides support and flexibility, 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.
  • How does cartilage grow?

    Cartilage grows by appositional growth (matrix secreted on cartilage surface) and interstitial growth (chondrocytes divide and secrete matrix from within).

  • List four major functions of bones.
    • Support for body and organs
    • Protection of brain and vital organs
    • Anchorage for muscles
    • Mineral and growth factor storage
  • What is hematopoiesis and where does it occur?

    Hematopoiesis is blood cell formation occurring in the red marrow cavities of certain bones.

  • How are bones classified by shape?
    • Long bones: longer than wide, limb bones
    • Short bones: cube-shaped, wrist and ankle
    • Flat bones: thin, flat, slightly curved
    • Irregular bones: complicated shapes like vertebrae
  • What are the two main types of bone tissue?

    Compact bone is dense and smooth; spongy bone consists of a honeycomb of trabeculae with spaces filled by marrow.

  • Describe the structure of a typical long bone.

    Long bones have a diaphysis (shaft of compact bone with medullary cavity), epiphyses (ends with compact outside and spongy inside), and membranes including periosteum and endosteum.

  • What is the periosteum and its layers?

    The periosteum is a double-layered membrane covering bone surfaces except joints, with an outer fibrous layer and an inner osteogenic layer containing stem cells.

  • What is the function of osteoprogenitor cells?

    Osteoprogenitor cells are mitotically active stem cells that differentiate into osteoblasts or bone-lining cells.

  • What role do osteoblasts play in bone tissue?

    Osteoblasts are bone-forming cells that secrete unmineralized bone matrix called osteoid, which contains collagen and calcium-binding proteins.

  • What are osteocytes and their function?

    Osteocytes are mature bone cells in lacunae that maintain bone matrix and act as stress sensors to regulate remodeling.

  • What is the function of osteoclasts?

    Osteoclasts are large multinucleate cells that resorb bone by secreting enzymes and acids to break down matrix.

  • What is an osteon and its components?

    An osteon is the structural unit of compact bone, consisting of concentric lamellae around a central canal containing blood vessels and nerves.

  • What are canaliculi and their function?

    Canaliculi are tiny canals connecting lacunae and central canal, allowing osteocytes to communicate and exchange nutrients and wastes.

  • What are the organic and inorganic components of bone matrix?
    • Organic: cells and osteoid (collagen and ground substance) provide tensile strength.
    • Inorganic: hydroxyapatites (calcium phosphate crystals) provide hardness and resistance to compression.
  • What is endochondral ossification?

    Endochondral ossification forms most bones by replacing hyaline cartilage models with bone, starting at a primary ossification center in the diaphysis.

  • What is intramembranous ossification?

    Intramembranous ossification forms flat bones from mesenchymal fibrous membranes without a cartilage stage.

  • How do long bones grow in length postnatally?

    Long bones grow by interstitial growth at the epiphyseal plate, involving zones of proliferation, hypertrophy, calcification, and ossification.

  • What hormones regulate bone growth?
    • Growth hormone: stimulates epiphyseal plate activity.
    • Thyroid hormone: modulates growth hormone effects.
    • Sex hormones: promote growth spurts and epiphyseal plate closure.
  • What is bone remodeling and which cells are involved?

    Bone remodeling is the continuous process of bone deposit by osteoblasts and bone resorption by osteoclasts, regulated by hormones and mechanical stress.

  • How does parathyroid hormone (PTH) affect bone remodeling?

    PTH is released in response to low blood calcium, stimulating osteoclasts to resorb bone and release calcium into the blood.

  • What is Wolff's law in bone physiology?

    Wolff's law states that bones grow or remodel in response to mechanical stress to become stronger where needed.

  • What are the stages of bone fracture repair?
    1. Hematoma formation
    2. Fibrocartilaginous callus formation
    3. Bony callus formation
    4. Bone remodeling
  • What causes osteoporosis and who is most at risk?

    Osteoporosis is caused by bone resorption exceeding deposit, leading to decreased bone mass; postmenopausal women are most at risk due to estrogen loss.

  • What is Paget's disease of bone?

    Paget's disease involves excessive and disorganized bone remodeling, resulting in weak, deformed bones with a high ratio of spongy to compact bone.