Skeletal system - Part 2 Flashcards
what does compact bone contain
haversian systems called osteons
how are osteons produced
bony remodeling
what is bony remodeling
removal of existing bone by osteoclasts and redeposition of new bone by osteoblasts
how big are the haversian systems
same size of an osteoclast ~200 micrometers in diameter
what is the outer margin of the osteon deliminted by
cement line
what invades the empty canal
osteoblasts
describe the ultrastructure of compact bone
concentric bony lamellae laid down by successive layers of osteoblasts
how do osteoblasts mature
they get trapped in lacunae in osteoid matrix and mature into osteocytes
what are osteocytes connected by
canaliculi
what do canaliculi use to communicate
gap junctions
what is the center of each osteon
haversian canal
where are the blood vessels and nerves located that supply osteocytes
in the haversian canal
what connects longitudinal haversian canals
transverse Volkmann’s canals
how are waste and nutrients exchanged in compact bone
via haversian vessels
how are haverisian systems oriented in relation to the long axis of bone
parallel along tension lines
what are interstitial systems
inactive Haversian canals
where is the haversian system located
only compact lamellar bone, not spongy woven bone
what is outer periphery of cortical bone arranged in
circumferential lamellae
what covers the periphery of cortical bone
periosteum
what is bone growth controlled by
growth hormone, thyroid hormone, and sex hormones
what are the ways to make bone
endochondral ossification and intramembranous ossification
what happens in endochondral ossification
replacement of cartilage precursor by bone
what is the end result of endochondral ossification
woven bone is extensively remodeled by resorption and appositional growth -> lamellar bone
where is lamellar bone located
long bones, vertebrae, pelvis, and base of skull