Skeletal System

synovial cavity

contains the synovial fluid

synovial fluid

lubricates the articular surfaces of the opposing bones

articular cartilage

a layer of hyaline cartilage that create a smooth surface to reduce friction

flexion movement

decrease in the angle between bones

extension movement

increase in the angle between bones

abduction movement

movement away from the body midline

adduction movement

movement toward the body midline

circumduction movement

movement of a distal part in a circular motion

rotation movement

movement on a pivot in a circular motion

supination movement

palm movement from posterior to anterior

pronation movement

palm movement from anterior to posterior

inversion movement

sole movement in a medial direction

eversion movement

sole movement in a lateral direction

dorsiflexion movement

movement of the foot dorsally (point toes up)

plantar flexion movement

movement of the foot inferiorly (stand on toes)

hinge joint

rounded bone fits into concave bone; flexion and extension (elbow joint)

pivot joint

rounded bone fits into depression; rotation and supination/pronation

ball and socket joint

ball-shaped head fits into cup-like depression; all angular movements and rotation

central, vertical axis of the body, including the skull, vertebral column, and thoracic cage

axial skeleton

all bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton

appendicular skeleton

long bone

short bone

flat bone

irregular bone

functions of skeletal system

support the body, protect soft organs, facilitate movement, store minerals and fats, blood cell formation

bone markings

surface features of bones, sites for muscle, tendon, and ligament attachment, passage for nerve and blood cells

projections

grow out from the bone surface

depressions

indentation

bone that surrounds yellow marrow

compact bone

trabeculae (small needle like pieces of bone) with many open spaces, holds red marrow

spongy bone

hemapoptosis takes place

red marrow

fat is stored

yellow marrow

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

epiphysis

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

diaphysis

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

articular cartilage

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

periosteum

completely ossified remnant of the epiphyseal plate

epiphyseal line

hollow region of diaphysis; filled with yellow marrow

medullary cavity

concentric rings of calcified matrix

lamellae

small spaces in bone or cartilage tissue that cells occupy

lacunae

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

central canal

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

osteon

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

Volkmann's canal

mature bone cell

osteocyte

bone forms from fibrous cartilage

intramembranous ossification

bone forms with hyaline cartilage,

endochondral ossification

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

remodeling

break in a bone

fracture

break that does not penetrate the skin

closed simple

broken bone that penetrates through the skin

open compound

bone breaks all the way through

complete fracture

bone does not break all the way through

incomplete fracture

bone breaks incompletely

greenstick

disease that causes gradual loss of bone density and strength, gradual collapse of the vertebrae

osteoperosis

osteocyte

a mature bone cell

compact bone

hard, dense bone tissue that is found in the diaphysis of a long bone

yellow marrow

fatty tissue found in the medullary cavity of most adult long bones

cancellous bone

spongy bone

red marrow

produces blood cells

ossification

Bone formation

epiphysis

end of the long bone

trabeculae

bony portions of the spongy bone that surround the open spaces

diaphysis

elongated shaft of a long bone

osteoblast

bone-building cells

epiphysial line

where bone growth takes place

hydroxyapetite

large crystal-like molecule in bones

osteoclast

break down bone

periosteum

double-layered connective tissue that covers and nourishes the bone

haversian canal

any of the many tiny canals that contain blood vessels and connective tissue and that form a network in bone