axial skeleton

the portion of the skeleton that supports and protects the organs of the head, neck, and trunk

appendicular skeleton

the bones of the pelvic and pectoral girdles and their appendages

irregular bones

jawbone, vertebrae, other bones that do not fit into other categories

flat bones

ribs, sternum, certain skull bones

long bones

humerus, radius, ulna, femur, fibula, tibia

short bones

carpals, tarsals

cartilage

a firm but flexible form of connective tissue

ossification

the laying down of new bone material by osteoblasts

osteoblast

a cell that builds and mineralizes new bone

joint

the point where two bones come together

ligament

a band of connective tissue that holds a joint together

periosteum

a layer of fibrous connective tissue that convers the outer surface of bones, except the joint ends of long bones

spongy bone

the type of bone that contains many small spaces, usually located in the ends of long bones

compact bone

dense, hard bone tissue made of tightly packed osteons

osteon

the subunit that makes up compact bone

osteocyte

a living bone cell resident in an osteon

Haversian canal

the channel within an osteon that contains the capillaries and nerves that service the osteon's osteocytes

growth plate

a plate of cartilage at each end of a long bone where bone growth takes place in children and adolescents

osteoclast

a type of cell that breaks down bone tissue

Joints

often classified according to how the two bones move in relation to one another

three types of joints

immovable joints, slightly movable joints, freely movable joints

freely movable joints

pivot joints, gliding joints, ball-and-socket joints, hinge joints

skeletal system

protection, storage site, production, and support

pivot joint

top two vertebrate; enable the head to rotate and swivel

gliding joints

wrist and ankle bones; limited lateral and vertical movement

ball-and-socket joints

hip and shoulder joints; cerates rotating movement in (basically) all directions

hinge joints

bend only in one direction; knee, elbow, knuckles