Question | Answer |
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 | 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 is required and where smooth surfaces facilitate movement |
central canal | longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal |
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 |
endosteum | delicate membranous lining of a bone’s medullary cavity |
epiphyseal line | completely ossified remnant of the epiphyseal plate (also, growth plate) |
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 hematoma | blood clot that forms at the site of a broken bone |
fracture | broken bone |
hematopoiesis | production of blood cells, which occurs in the red marrow of the bones |
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 |
irregular bone | bone of complex shape; protects internal organs from compressive forces |
lacunae | 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 |
osseous tissue | bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton |
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 |
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 | 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 |
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 |
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 | 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 |
axial skeleton | central, vertical axis of the body, including the skull, vertebral column, and thoracic cage |
appendicular skeleton | bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton |
abduction | movement in the coronal plane that moves a limb laterally away from the body; spreading of the fingers |
adduction | movement in the coronal plane that moves a limb medially toward or across the midline of the body; bringing fingers together |
cartilaginous joint | oint at which the bones are united by hyaline cartilage or fibrocartilage |
extension | movement that increases the angle of a joint (straightens the joint) |
fibrous joint | joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue |
flexion | movement that decreases the angle of a joint (bends the joint) |
joint cavity | space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones |
ligament | strong band of dense connective tissue spanning between bones |
synovial fluid | thick, lubricating fluid that fills the interior of a synovial joint |
synovial joint | joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule |
tendon | dense connective tissue structure that anchors a muscle to bone |
uniaxial joint | joint that allows for motion within only one plane (one axis) |
biaxial joint | joint that allows for movements within two planes (two axes) |
multiaxial joint | a joint that allows for movements within three planes (three axes) |