B6,052 Prework 1: Bone Architecture Flashcards
function of hydroxyapatite crystals in bone
prevents:
-diffusion of metabolites
-interstitial growth
both of these occur in cartilage (which is avascular)
canalicular system
tiny canals extending from one lacuna to another
gap junction
facilitates communication between osteocytes (mature bone cells) responsible for the maintenance of bone
vascularity of bone
bone cells must be in close proximity to capillaries
composition of bone
cells, fibers, and ground substance
types of bone cells
bone lining cells (osteoprogenitor cells)
osteoblasts
osteocytes
osteoclasts
how does bone elongation occur
proliferation of cartilage
is bone dead?
no!!!!!!!!!!!!!!!!
BONE IS NOT DEAD!
why is bone not dead
10% remodeling occurs annually
highly vascular and blood vessels are accompanied by sympathetic and pain fibers
names for denser outer bone
compact
lamellar
Haversian
cortical
names for spongy bone
cancellous
trabecular
description of trabecular bone
3 dimensional lattice of branching bony spicules
forms trabeculae around marrow spaces
epiphysis
end of long bone
metaphysis
growth area between shaft and head of long bone
diaphysis
shaft portion of long bone
periosteum
dense connective tissue surrounding bone
has osteogenic potential
made up of osteoprogenitor cells
where is periosteum absent
articulating surfaces and at the attachments of tendons and ligaments
endosteum
lines marrow cavity
also has osteogenic potential
osteoprogenitor cells line the inside of the marrow cavity
bone pattern of skull
external and internal tables (compact bone) inner diploe (cancellous bone)
factors determining the set point of peak bone mass
- genetics
- nutrition (ca, vit D)
- physical activity (mechanical loading, muscle strength)
- hormonal status
- age
- overall health
genetic factors that may impact PBM
polymorphisms in vit D receptor, LRP5/6 (males)
RANK, OPG, RANKL
effects of menopause on peak bone mass
decreased serum estrogen
increased IL-1, IL06, TNF levels
increased RANK, RANKL
increased osteoclastic activity
effects of aging on peak bone mass
decreased replication of osteoprogenitor cells
decreased synthetic activity of osteoblasts
decreased biologic activity of matrix bound growth factors
reduced physical activity
