Bone Flashcards
inorganic component is composed of:
organic component is composed of:
hydrocyapatite
collagen, glycosaminoglycans, proteoglycans, water
osteoclasts
bone resorption
osteoblasts
form and create new bone
osteocytes
trapped in ECM, regulate clast/blast activity
cortical = ______ bone
trabecular = ________ bone
compact
cancellous, spongy
cortical bone resists what?
compression, tension
what is the fundamental unit of cortical bone
osteon
What do you call the middle of cortical bone that has vessels and nerves
haversian canal
lacunae contain
osteocytes
what allows for communication between lacunae and ultimately reaches the haversian canals
canaliculi
What are lamellae?
concentric rings that contain lacunae
explain wolfe’s law
trabecular bone adapts and collagen organizes to adapt to magnitude and direction of stress
Does trabecular/cancellous bone have haversian canals and osteons?
no
What is the thin inner membrane called
the thin inner membrane called the endosteum
what is the thin outer membrane called
periosteum
is the periosteum present at articular surfaces
no
Why is bone being highly vascular a good thing?
- very high healing potential
- very metabolically active
cortical bone is stiff and brittle with a yield point ________ to ultimate strength
very close
brittle means
little deformation before failure
trabecular/cancellous bone is less stiff and is ductile, with a yield point ________ from ultimate strength
far
ductile means
bone deforms greatly before failure
___________ response means behavior of bone is dependent on rate load is applied
viscoelastic
fast loads mean what? slow loads?
fast:
increase strength, stiffness, and less ductile
slow:
less strength, stiffness, and more ductile
bending includes what forces? torsion?
bending: tension and compression
torsion: shear over entire material
bone is anisotropic. What does that mean
strength is dependent on direction of load application
bone is best suited for what forces?
compressive
how does muscle force influence bone?
- give load to bone, stimulating remodeling
- may decrease load/change nature of force to prevent fracture
what is the neutral axis of bone
location of bone with no stress (may result in less bone remodeling and weakness)
in long bones, the further away from the neutral axis, the _______ the shear stresses and greater remodeling stimulus
larger
why is mechanical loading good for bones?
it stimulates osteoblast activity to create new bone
T or F: we have some bone remodeling happening at all times
t
bone strain is greatest during ______ activities
dynamic
without _________, osteoclast activity predominates and bone mass decreases
remodeling stimuli
bone development begins with ____________ 6-7 weeks in utero
intramembranous ossification
what is endochondral ossification
bone develops at secondary ossification centers by replacing cartilage. starts 6-8 weeks after conception and continues into adulthood
