Chapter 6: The Skeletal System: Bone Tissue

Osteology

the study of bone structure and treatment of bone disorders

Hemopoiesis

the process of red bone marrow producing red blood cells, white blood cells, and platelets

Red bone marrow

is a connective tissue that consists of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of reticular fibers; stored in the hip bones, ribs, sternum, vertebrae, skull, and the proximal ends of the humerus and femur

Diaphysis

the long, cylindrical, main portion of the bone; the shaft

Epiphyses

the proximal and distal ends of the bone

Metaphyses

regions between the diaphysis and the epiphyses

Articular cartilage

a thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms a joint with another bone

Periosteum

tough connective tissue sheath and its associated blood supply that surrounds the bone surface where it is not covered by articular cartilage

Medullary cavity

the marrow cavity; a hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels. allows bone to have maximum strength with minimum weight

Endosteum

a thin membrane that lines the medullary cavity and the internal spaces of spongy bone

Osteoblasts

Synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, a process called bone deposition, and they initiate calcification

Osteocytes

cell maintains and monitors the tissue

Osteoclasts

cell breaks down extracellular matrix

Compact bone

strongest type of bone tissue; composed of repeating structural units called osteons

Spongy bone

does not contain osteons; consists of bone lamellae arranged in an irregular pattern of thin columns called bone trabeculae; filled with red or yellow bone marrow

Ossification

the process by which bone is formed

Endochondral Ossification

the replacement of cartilage by bone

Chondroblasts

secrete cartilage extracellular matrix, producing a cartilage model consisting of hyaline cartilage; perichondrium develops around the cartilage model

Reactive phase

a fracture hematoma forms from damaged blood vessel at fracture site; neutrophils, macrophages, and osteoclasts begin to remove damaged tissue (may last up to several weeks)

Reparative phase

fibrous cartilage callus formation (takes about 3 weeks) and bony callus formation (lasts about 3-4 months)

Open fracture

the broken ends of the bone protrude through the skin

Comminuted

the bone is splintered, crushed, or broken into pieces

Greenstick

one side of the bone is broken and the other side bends; occurs only in children

Impacted

one end of the fractured bone is forcefully driven into the interior of the other

Pott

fracture of the distal end of the fibula, with serious injury of the distal tibial articulation

Colles

fracture of the distal end of the radius, and the distal fragment is displaced posteriorly

Vertebral compression fracture (VCF)

the vertebral body of one or more vertebrae fractures and becomes compressed into a wedge-shape

Osteoporosis

a condition of porous bones

Osteopenia

low bone mass

Osteoarthritis

the degeneration of articular cartilage leading to bony ends touch

Osteomyelitis

an infection of bone characterized by high fever, sweating, chills, pain, nausea, pus, edema, and localized warmth; usually caused by staph aureus (bacteria)

Osteosarcoma

is bone cancer that primarily affects osteoblasts and occurs most often in teenagers during their growth spurt

Epiphyseal plate

a layer of hyaline cartilage in the metaphysis of a growing bone

Rickets

growing bones become “soft” and bowed legs forms due to inadequate calcification of the extracellular bone matrix, usually from vitamin D deficiency; when this occurs in adults it is called osteomalacia.