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Anatomy & Physiology: Skeletal System and Bone Biology

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Terms in this set (23)

  • Functions of the skeletal system
    • Support for body and soft organs
    • Protection for brain, spinal cord, and vital organs
    • Storage of minerals and growth factors
    • Blood cell formation (hematopoiesis) in marrow cavities
  • Classification of bones by shape
    • Long bones: longer than wide
    • Short bones: cube-shaped (e.g., wrist, ankle)
    • Flat bones: thin, flat, slightly curved
    • Irregular bones: complicated shapes
  • Define process, ramus, trochanter, tuberosity
    • Process: any bony prominence
    • Ramus: armlike bar of bone
    • Trochanter: large, blunt irregular surface
    • Tuberosity: rounded projection
  • Define tubercle, facet, fossa, foramen, fissure
    • Tubercle: small rounded projection
    • Facet: smooth, nearly flat articular surface
    • Fossa: shallow depression
    • Foramen: round or oval opening through bone
    • Fissure: slit-like groove or cleft
  • Organic components of bone matrix and their role
    Includes osteoid, collagen fibers, and ground substance (proteoglycans and glycoproteins). Collagen provides tensile strength and flexibility.
  • Inorganic components of bone matrix and their role
    Mineral salts (mainly calcium phosphate crystals called hydroxyapatites) make up 65% of bone mass and provide hardness and resistance to compression.
  • Compare compact bone and spongy bone
    Compact bone: dense, organized into osteons, forms outer layer and diaphysis wall.
    Spongy bone: porous, made of trabeculae, reduces weight, found in epiphyses with red marrow.
  • What is an osteon and its components?
    Structural unit of compact bone including:
    • Lamellae: concentric bone matrix layers
    • Central canal: blood vessels and nerves
    • Lacunae: cavities with osteocytes
    • Canaliculi: channels connecting lacunae
    • Osteocytes: mature bone cells
    • Perforating canals: connect central canals
  • Function and location of red bone marrow in infants vs adults
    Red marrow produces blood cells.
    Infants: found in medullary cavities and spongy bone.
    Adults: mainly in trabecular spaces of femur, humerus heads, and flat bones.
  • Define osteoblast, osteogenesis, osteoid, osteoclast, osteolysis
    • Osteoblast: bone-forming cell
    • Osteogenesis: bone formation process
    • Osteoid: unmineralized organic matrix
    • Osteoclast: bone-resorbing cell
    • Osteolysis: breakdown of bone tissue
  • How do osteocytes communicate?
    Via canaliculi, tiny channels connecting lacunae, allowing exchange of nutrients and chemical signals.
  • Summary of endochondral ossification
    Bone forms by replacing hyaline cartilage. A bone collar forms, cartilage calcifies and dies, periosteal bud invades, spongy bone forms, diaphysis elongates, secondary ossification in epiphyses, cartilage remains only at articular surfaces and epiphyseal plates.
  • What is the epiphyseal line?
    Remnant of the epiphyseal growth plate after bone growth ends; marks where cartilage was replaced by bone.
  • Factors affecting bone remodeling
    • Mechanical stress
    • Osteoblasts (build bone)
    • Osteoclasts (resorb bone)
    • Hormones (PTH, growth hormone, thyroid hormone)
    • Nutrition (protein, vitamins A, C, D, minerals)
    • Age (bone mass decreases with age)
  • Five zones of long bone growth at epiphyseal plate
    • Resting zone: anchors plate
    • Proliferation zone: cartilage cells divide
    • Hypertrophic zone: cartilage cells enlarge
    • Calcification zone: matrix calcifies, cells die
    • Ossification zone: osteoblasts deposit bone matrix
  • Effect of mechanical stress on bone
    Bone remodels and grows thicker where stressed; trabeculae align with stress lines; large projections develop where muscles attach.
  • Role of vitamins A and C in bone formation
    Vitamin A: supports normal bone growth and remodeling.
    Vitamin C: necessary for collagen synthesis, supporting bone matrix formation.
  • Organs involved in vitamin D production
    Skin, liver, and kidneys collaborate to produce active vitamin D.
  • Effects of growth hormone and thyroid hormone on bones
    Growth hormone: stimulates epiphyseal plate activity, promoting length growth.
    Thyroid hormone: modulates growth hormone and supports normal bone development.
  • Define osteomalacia, rickets, osteoporosis, achondroplasia, dwarfism
    • Osteomalacia: adult bone softening from poor mineralization
    • Rickets: childhood bone deformities from vitamin D/calcium deficiency
    • Osteoporosis: decreased bone mass, fragile bones
    • Achondroplasia: genetic short limb disorder
    • Dwarfism: unusually short stature from various causes
  • Effects of parathyroid and thyroid hormones on blood calcium
    Parathyroid hormone (PTH): raises blood calcium by stimulating osteoclasts and kidney calcium conservation.
    Thyroid hormone: regulates metabolism and supports bone growth; calcitonin lowers blood calcium by inhibiting osteoclasts.
  • Three types of cartilage and their locations
    • Hyaline cartilage: joints, ribs, nose, respiratory tract
    • Fibrocartilage: intervertebral discs, pubic symphysis, knee menisci
    • Elastic cartilage: external ear, epiglottis
  • Which heals faster: bone injury or cartilage injury? Why?
    Bone heals faster due to better blood supply, allowing oxygen, nutrients, and repair cells to reach injury. Cartilage has little to no direct blood supply.