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Bone and Bone Tissue - Anatomy & Physiology

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Terms in this set (20)

  • Functions of the skeletal system

    Protection, Support, Movement, Mineral storage and acid-base homeostasis, Blood cell formation, Fat storage, and Hormone production.

  • Classification of bones by shape

    Long (longer than wide), Short (cube-shaped), Flat (thin and broad), Irregular (complex shapes), and Sesamoid (small, flat, within tendons).

  • Difference between axial and appendicular skeleton

    Axial skeleton forms the long axis (skull, vertebrae, ribs). Appendicular skeleton includes limbs and girdles attaching limbs to axial skeleton.

  • Structure of a long bone

    Includes diaphysis (shaft), epiphyses (ends), medullary cavity with marrow, compact bone, spongy bone, periosteum, and endosteum.

  • Periosteum layers and function

    Double-layered membrane: fibrous layer (dense irregular connective tissue with Sharpey’s fibers) and osteogenic layer (contains osteogenic stem cells). Anchors tendons and ligaments.

  • Types of bone marrow and their functions

    Red marrow produces blood cells (hematopoiesis). Yellow marrow stores fat in adipocytes.

  • Composition of bone extracellular matrix

    Inorganic matrix (~65%) mainly hydroxyapatite crystals for strength. Organic matrix (osteoid, ~35%) mainly collagen and proteins for flexibility and tensile strength.

  • Roles of osteoblasts, osteocytes, and osteoclasts

    Osteoblasts build bone by secreting matrix. Osteocytes maintain bone matrix. Osteoclasts resorb bone by secreting acid and enzymes.

  • Osteopetrosis

    Defective osteoclasts cause excessive bone mass that is weak and brittle. Can cause nerve trapping and reduced marrow space.

  • Osteoporosis

    Bone resorption exceeds deposition, leading to brittle bones and increased fracture risk. Caused by calcium/vitamin D deficiency, hormonal changes, and aging.

  • Histology of compact bone

    Composed of osteons with concentric lamellae, central (Haversian) canal, lacunae with osteocytes, and canaliculi connecting lacunae.

  • Histology of spongy bone

    Consists of trabeculae with lamellae, lacunae, and canaliculi but no osteons. Blood supply comes from bone marrow vessels.

  • Intramembranous ossification

    Bone forms directly from mesenchymal membrane; forms flat bones like skull and clavicles. Spongy bone forms first, then compact bone.

  • Endochondral ossification

    Bone forms by replacing hyaline cartilage model; forms most bones below the head. Compact bone forms first, then spongy bone inside.

  • Zones of the epiphyseal plate in longitudinal bone growth

    Reserve cartilage, proliferation (mitosis), hypertrophy/maturation, calcification, and ossification zones involved in lengthening bones.

  • Appositional growth

    Growth in bone thickness by osteoblasts adding new circumferential lamellae under periosteum and osteoclasts resorbing inner bone to enlarge medullary cavity.

  • Hormones affecting bone growth

    Growth hormone promotes chondrocyte mitosis and osteoblast activity. Testosterone increases appositional growth and mitosis. Estrogen has similar but less pronounced effects.

  • Bone remodeling regulation

    Controlled by hormonal feedback loops (PTH increases blood calcium, calcitonin decreases it) and mechanical stress (Wolff’s Law).

  • Steps of fracture healing

    Hematoma formation, soft callus formation by fibroblasts and chondroblasts, hard bone callus formation by osteoblasts, and remodeling to secondary bone.

  • Types of bone fractures

    Includes spiral, compression, comminuted, avulsion, greenstick, and epiphyseal fractures, classified by break pattern and displacement.