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Humanities Libertexts

Key Terms

  • Page ID
    19487
  • articular cartilage
    thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber
    articulation
    where two bone surfaces meet
    bone
    hard, dense connective tissue that forms the structural elements of the skeleton
    canaliculi
    (singular = canaliculus) channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients
    cartilage
    semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement
    central canal
    longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal
    closed reduction
    manual manipulation of a broken bone to set it into its natural position without surgery
    compact bone
    dense osseous tissue that can withstand compressive forces
    diaphysis
    tubular shaft that runs between the proximal and distal ends of a long bone
    diploë
    layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones
    endochondral ossification
    process in which bone forms by replacing hyaline cartilage
    endosteum
    delicate membranous lining of a bone’s medullary cavity
    epiphyseal line
    completely ossified remnant of the epiphyseal plate
    epiphyseal plate
    (also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length
    epiphysis
    wide section at each end of a long bone; filled with spongy bone and red marrow
    external callus
    collar of hyaline cartilage and bone that forms around the outside of a fracture
    flat bone
    thin and curved bone; serves as a point of attachment for muscles and protects internal organs
    fracture
    broken bone
    fracture hematoma
    blood clot that forms at the site of a broken bone
    hematopoiesis
    production of blood cells, which occurs in the red marrow of the bones
    hole
    opening or depression in a bone
    hypercalcemia
    condition characterized by abnormally high levels of calcium
    hypocalcemia
    condition characterized by abnormally low levels of calcium
    internal callus
    fibrocartilaginous matrix, in the endosteal region, between the two ends of a broken bone
    intramembranous ossification
    process by which bone forms directly from mesenchymal tissue
    irregular bone
    bone of complex shape; protects internal organs from compressive forces
    lacunae
    (singular = lacuna) spaces in a bone that house an osteocyte
    long bone
    cylinder-shaped bone that is longer than it is wide; functions as a lever
    medullary cavity
    hollow region of the diaphysis; filled with yellow marrow
    modeling
    process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another
    nutrient foramen
    small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment
    open reduction
    surgical exposure of a bone to reset a fracture
    orthopedist
    doctor who specializes in diagnosing and treating musculoskeletal disorders and injuries
    osseous tissue
    bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton
    ossification
    (also, osteogenesis) bone formation
    ossification center
    cluster of osteoblasts found in the early stages of intramembranous ossification
    osteoblast
    cell responsible for forming new bone
    osteoclast
    cell responsible for resorbing bone
    osteocyte
    primary cell in mature bone; responsible for maintaining the matrix
    osteogenic cell
    undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts
    osteoid
    uncalcified bone matrix secreted by osteoblasts
    osteon
    (also, Haversian system) basic structural unit of compact bone; made of concentric layers of calcified matrix
    osteoporosis
    disease characterized by a decrease in bone mass; occurs when the rate of bone resorption exceeds the rate of bone formation, a common occurrence as the body ages
    perforating canal
    (also, Volkmann’s canal) channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum
    perichondrium
    membrane that covers cartilage
    periosteum
    fibrous membrane covering the outer surface of bone and continuous with ligaments
    primary ossification center
    region, deep in the periosteal collar, where bone development starts during endochondral ossification
    projection
    bone markings where part of the surface sticks out above the rest of the surface, where tendons and ligaments attach
    proliferative zone
    region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate
    red marrow
    connective tissue in the interior cavity of a bone where hematopoiesis takes place
    remodeling
    process by which osteoclasts resorb old or damaged bone at the same time as and on the same surface where osteoblasts form new bone to replace that which is resorbed
    reserve zone
    region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis
    secondary ossification center
    region of bone development in the epiphyses
    sesamoid bone
    small, round bone embedded in a tendon; protects the tendon from compressive forces
    short bone
    cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion
    skeletal system
    organ system composed of bones and cartilage that provides for movement, support, and protection
    spongy bone
    (also, cancellous bone) trabeculated osseous tissue that supports shifts in weight distribution
    trabeculae
    (singular = trabecula) spikes or sections of the lattice-like matrix in spongy bone
    yellow marrow
    connective tissue in the interior cavity of a bone where fat is stored
    zone of calcified matrix
    region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis
    zone of maturation and hypertrophy
    region of the epiphyseal plate where chondrocytes from the proliferative zone grow and mature and contribute to the longitudinal growth of the epiphyseal plate
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