bones

Long bones: longer than wide (humerus, femur)

Short bones: dimensions roughly equal (carpal bones, tarsal bones)

Flat bones: thin and relatively broad (parietal bones in the skull, ribs, scapulae)

Irregular bones: complex; don’t fit in any other category (vertebrae, pelvis)

Diaphysis: central shaft of long bone; surrounds diaphysis

Marrow cavity: surrounded by diaphysis; contains bone marrow

Bone marrow: soft fatty tissue that fills marrow cavities 

Epiphyses: expanded portions at the ends of diaphysis; covered with articular cartilage

Articular Cartilage: covers epiphyses 

Compact bone: dense bone; fills diaphysis

Spongy bone: resembles a network of bony rods/struts separated by space; fills epiphyses

Periosteum: outer surface of a bone

Endosteum: covers the spongy bone of the marrow and other inner surfaces

Lacunae: small pockets found between narrow sheets of calcified matrix known as lamellae

Lamellae: narrow sheets of calcified matrix 

Canaliculi: small channels that radiate through the matrix and link lamellae to blood vessels; enable nutrient and waste exchange through cytoplasmic extensions

Osteon: functional unit of compact bone

Trabeculae: found in spongy bone; formed by lamellae

Osteocytes: found in lacunae; mature bone cells; maintain bone structure by recycling calcium salts and assisting in repairs

Osteoclasts: dissolve the bony matrix and release osteolysis

Osteoblasts: produce new bone matrix; as osteoclasts remove, osteoblasts add

Ossification: production of new bone