Bone Growth and Development Flashcards
(24 cards)
what is bone?
a living tissue, the framework of the body the hardest of all connective tissues
what is the composition of bone?
67% inorganic components
10% H2O
23% cells and tissues
what kind of forces are bones typically resistant too?
compression
tensile (pulling force separating axial ends)
torsional (twisting force separating along axis of bone)
what is bone organization consist of?
cells that are isolated in a matrix of collagen fibers impregnated within a vast amount of calcium salts
what are two primary calcium salts?
calcium phosphate
hydroxyapatite
what is hydroxyapatite
crystal-like molecules with 10 Ca^2+ ions produced by osteoblast
what are the cells of the bone?
osteoblast
osteoclast
osteocytes
what is an osteoblast?
a single nucleated cell that synthesizes the bone matrix and remodeling of bone
what is an osteoclast?
a multi-nucleated cell that causes the breakdown of bone tissue though a phagocytic process
what is an osteocyte?
the most common cell type which is a signaling cell that regulates bone mass
what is longitudinal bone growth (LBG)?
bone growth extending the length of bone
where does LBG occur at?
the epiphyseal plate aka growth plates
what are the growth plates?
they are simple structures made from a hyaline-cartilage which is connective fibers made from primarily collagen, chondrocytes, and proteoglycans
what are the 3 zones of the growth plate?
the resting, proliferation, and hypertrophic zones
what are resting zone chondrocytes?
stem-like cells that serve as the primary pool for growth
what are proliferation zone chondrocytes?
resting zone chondrocytes that have differentiated into proliferation
what are hypertrophic zone chondrocytes?
chondrocytes that calcify the proteoglycan matrix of the growth plate
T/F the GH-IGF-1 axis is fundamental and a very potent stimulator of bone growth
true
what is the axis directly driven by?
the release of GH
what does excess GH cause?
acromegaly
what causes a GH deficiency?
Genetics, diseases, and injury
T/F both GH and IGF-1 directly stimulate longitudinal bone growth by local action on the growth plate
True
what is estrogens primary role in bone growth?
stimulate bone mineralization
stimulate production of vascular endothelial growth factor (VEGF)
stimulating growth plate maturation
increase proliferation of osteoblasts
indirectly enhance the GH-IGF-1 axis
