Bone Overview Flashcards
Wolff’s law
a bone, normal or abnormal, develops teh structure most suited to resist the forces acting upon it
tissues of bone
cartilage bone bone marrow (fat + hemopoietic stem cells) blood vessels nerves
if force is applied to the bone surface
the surface will respond with bone deposition
if force is removed from a bone surface
the bone will be removed
removing and deposition of bone is called
remodelling
3 regions of long bone
epiphysis
metaphysis
diaphysis
metaphysis and diaphysis are made from
thick cortical bone
flat bones
skull, plevis, scapula
–mostly cortical, but can have a trabecular core
cortical bone comprises
80% of skeleton
cortical bone has
a slow turnover and is less elastic
cortical bone is made of
packed Haversian systems (osteons) connected by Volkmann’s canals + interstial lamellae
-collagen fibers organized in parallel between a few cells
cancellous bone aka
spony, trabecular
cancellous bone has
high turnover, more elastic
cancellous bone is made of
bony struts organized into a lose network
- ->these are highly porous and contain bone marrow; increase pores in osteoporosis
- usually in medualla
- rapidly deposited and does not require a cartilage template
microscopic lavel
cortical and cancellous bone
microscopic level
woven bone and lamellar bone
woven bone
immature or pathological bone with randomly organized fibers (not stress-oriented)
–higher turnover (laid quickly) and higher osteocytes than lammellar
woven bone in adults is always
pathological/fracture
collagen in woven bone
not parallel, not as strong as lamellar
lamellar bone is created by
removeling of woven bone (stress-oriented); stronger- less flexible, has < turnoverrate
metabolic unit of bone
osteoclasts resorb bone, digesting mineral and organic matrix together
osteoblatss appear in resorption site and produce unmineralized organic matric with mineralization lagging slightly behind
mineralizaton completes procress
osteoporosis
loss of total bone volume
cortical nad medullary bone become thinner and decrease in number
both mineral and organic matrix are equally effected; both are diminished
osteomalacia
decrease bone secondary to mineralization
increased deposition of osteoid (unmineralized bone matrix)
hyaline articular cartialge
lines the joint
does not grow after skeletal maturity and is different from physeal cartialge
if you rip hylaine articular cartilage
it cannot repair–>replaced by fibrocartilage or bone once its damaged; serves as an excellent frictionless surface for the joint
bone develops through two mechanisms
endochondrial ossification- cartilage present
membranous ossification- cartilage not present
growth plate-
longitudinal growth that follows a cartilagenous template
zones of bone
epiphysis reserve zone zone of prolifer zone of hypertrophy primary spongiosa
