Chapter 7 Vocabulary

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

diaphysis

tubular shaft that runs between the proximal and distal ends of a long bone

epiphyseal line

completely ossified remnant of the epiphyseal plate

hypocalcemia

condition characterized by abnormally low levels of calcium

long bone

cylinder-shaped bone that is longer than it is wide; functions as a lever

endosteum

delicate membranous lining of a bone's medullary cavity

compact bone

dense osseous tissue that can withstand compressive forces

fracture

broken bone

osteoclast

cell responsible for resorbing bone

perforating canal

channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum

osteoid

uncalcified bone matrix secreted by osteoblasts

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

bony callus

a callus of immature bone that replaces the fibrocartilaginous callus

fibrocartilaginous callus

a cartilaginous matrix that bulges externally and later calcifies - second stage of fracture repair

lamella

a layer such as of bone matrix in an osteon of compact bone

osteon

basic structural unit of compact bone; made of concentric layers of calcified matrix

ossification

bone formation

irregular bone

bone of complex shape; protects internal organs from compressive forces

osseous tissue

bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton

osteoblast

cell responsible for forming new bone

ossification center

cluster of osteoblasts found in the early stages of intramembranous ossification

hypercalcemia

condition characterized by abnormally high levels of calcium

yellow marrow

connective tissue in the interior cavity of a bone where fat is stored

red marrow

connective tissue in the interior cavity of a bone where hematopoiesis takes place

short bone

cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion

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

periosteum

fibrous membrane covering the outer surface of bone and continuous with ligaments

bone

hard, dense connective tissue that forms the structural elements of the skeleton

medullary cavity

hollow region of the diaphysis; filled with yellow marrow

diploë

layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones

central canal

longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal

perichondrium

membrane that covers cartilage

skeletal system

organ system composed of bones and cartilage that provides for movement, support, and protection

osteocyte

primary cell in mature bone; responsible for maintaining the matrix

intramembranous ossification

process by which bone forms directly from mesenchymal tissue

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

endochondrial ossification

process in which bone forms by replacing hyaline cartilage

secondary ossification center

region of bone development in the epiphyses

primary ossification center

region, deep in the periosteal collar, where bone development starts during endochondral ossification

cartilage

semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement

epiphyseal plate

sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length

lacunae

spaces in a bone that house an osteocyte

trabeculae

spikes or sections of the lattice-like matrix in spongy bone

flat bone

thin and curved bone; serves as a point of attachment for muscles and protects internal organs

articular cartilage

thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber

spongy bone

trabeculated osseous tissue that supports shifts in weight distribution

osteogenic cell

undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts

articulation

where two bone surfaces meet

epiphysis

wide section at each end of a long bone; filled with spongy bone and red marrow