Bone Modeling and Remodeling Flashcards
what does load predictability like with bones?
long bones that are slightly curved
what is the periosteum?
outer fibrous layer: supportive function
inner osteogenic layer: adaptive response
what is the cellular component of bone?
osteoblats
osteocytes: osteoblasts in bone matrix
osteoclasts
what makes up the organic extracellular matrix of bone?
collagen
proteoglycans
glycosaminoglycans
what makes up the inorganic portion of bone?
calcium
phosphate
hydroxyapatite crystals
what does the unique design of bone allow?
animal to adapt to its mechanical environment
what does loading lead to?
deformation, stress, and then strain
what is stress?
amount of force per unit area that develops on a plane surface within a structure in response to an externally applied load
what is strain defined as?
localized change in dimension that occurs within a structure as it responds to externally applied loads
what is wolff’s law?
bone changes shape and strength, modeled and remodeled, in response to the magnitude and direction of strain
what does high strain cyclic fatigue do with cortical bone?
decreases stiffness and leads to bone strengthening
what is modeling?
bone formation along periosteal and endosteal surfaces
what is remodeling?
formed bone, normal lamellar or abnormal fiber bone, is replaced
resorption and bone formation
what properties of the bone change during resorption?
porosity increase
stiffness decreases
what does microtrauma of bone culminate in?
clinical injury that is sudden in onset and substantial in extent
what are some bad bone changes in response to exercise?
subchondral sclerosis can result from intense remodeling
microdamage/microfracture, intense resorption, and inferior subchondral bone and possible fracture
maladaptive or non-adaptive bone remodeling
what is being done in the thoroughbred industry to improve safety?
shoeing regulations
anabolic steroids banned
track approval process
synthetic tracks
training techniques
where is cancellous (trabecular) bone?
ends of long bones
where is compact (cortical) bone?
shaft of long bones
what cells make up the transport and communication system within bone?
osteocytes: osteoblasts trapped in bone matrix
how much of the bone wet weight is organic extracellular matrix?
21%
what makes up the strain environment?
strain magnitude
strain rate
strain frequency
strain distribution
number of loading cycles
rest-recovery periods
does wolff’s law involve both cortical and cancellous bone?
yes
what might cyclic loading during the resorption phase lead to?
bucked shins
dorsal cortical fracture
what are bucked shins?
periosteal new bone formation and inflammation
what adaptive changes occur in cancellous/trabecular bone?
micromodeling: trabecular bone in subchondral region strengthens
remodeling: resorption and deposition of lamellar bone
