Number of Bones in

the Axial Skeleton

Number of bones in

the Appendicular Skeleton

Functions of the 

skeletal system

Support

Storage of minerals

Blood cell production

Protection

Leverage

Thin, roughly parallel surfaces

ie. Cranial bones, sternum

Sutural Bones

(Wormian bones)

Irregular bones formed between cranial bones

Number, size, and shape vary

Realatively long and slender

ie. various bones of the limbs

Complex Shapes

ie. vertebrae, bones of pelvis,

facial bones

Small, flat, and somewhat shaped like sesame seed.

Develop in tendons of knee, hands, and feet

small and boxy

ie. bones of the wrist (carpals)

and ankles (tarsals)

Canal or meatus (large passageway)

Process (projection or bump)

Sinus (chamber within bone, usually filled with air)

Foramen (small rounded passageway)

Fissure (elongated cleft or gap)

Mature bone cells that cannot divide

Most numerous bone cell type

Maintain protein and mineral content of adjacent matrix

Produce new bony matrix (osteogenesis or ossification)

Become osteocytes once surrounded by bony matrix

Osteoprogenitor cells

(progenitor, ancestor)

Mesenchymal (stem) cells that produce cells that differentiate into osteoblasts

Important in fracture repair

Osteoclasts

(clast, to break)

Remove and remodel bone matrix

giant cells with 50+ nuclei

release acids and proteolytic enzymes to disolve matrix and release stored minerals

Reduction in growth hormone leads to reduced epiphyseal cartilage activity and short bones

Rare due to treatment with synthetic growth hormone