Bone formation Flashcards
Endochondral ossification
Bones of axial and appendicular skeleton,
Base of the skull
Cartilage by chondrocyte, later replaced with woven bone, and remodel to lamellar bone.
Woven bone occurs when
In adults,
after fracture and Paget’s disease
Membraneous ossification
Bones of calvarium (skull) and facial bone
Woven bone formed without cartilage
Later remodeled to lamellar bone
PTH
At low, intermittent level,
anabolic (building bone) on osteoblast, osteoclast
At chronic, high level,
catabolic (osteitis fibrosa cystica)
Estrogen
Inhibits apoptosis of osteoblasts
Induces apoptosis of osteoclasts
Achondroplasia
Failure of longitudinal bone growth
(endochondral ossification)
Constitutive FGFR3 actually inhibits chondrocyte proliferation.
> 85% sporadic mutation, associated with adv paternal age
Also autosomal dominant pattern.