Microscopic Anatomy of Bone

osteoprogenitor cells

stem cells destined to become bone cells

osteoprogenitor cells mature and become

osteoblasts

osteoblasts

secrete osteiod, forming bone matrix

osteocytes

bone cells that are trapped in bone; sense lack of stress

the basic unit of compact bone is the

osteon

osteon (Haversian System)

run parallel to the diaphysis; cylindrical structures

central canal

core- contains blood vessels and nerves

concentric lamellae

layers;rings;surrounds

osteocytes

mature osteocytes; inbtw layers of bone tissue (spider looking)

canaliculi

small spaces through which osteocyte appendages travel (communicate) (looks like legs of spider)

perforating canals

right angles/perp to central canals

lack osteons

cylinder units/not as strong

trabeculae contains

parallel lamellae

parallel lamellae

distributes stress from mechanical forces across framework

ossification

formation of bone connective tissue

what are the two patterns of ossification

intramembranous and endochondral ossification

intramembranous ossification

produces flat bones of the skull, some facial bones, mandible and central portion of the clavicle

bones develop from the

mesenchyme membrane

endochondral ossification

formation of most bones of skeleton

interstitial growth

a long bone’s growth in length

apositional growth

growth in a bone’s diameter

epiphyseal plate

site of interstitial growth, consists of 5 distinct microscopic zones

zone 2 (hyperplasia)

zone of proliferating cartilage

zone 3 (hypertrophy)

zone of hypertrophic cartilage