Dougherty Part 1 Flashcards
RANK receptor is found on what and what does it allow for
osteoclast precursor
allow for osteoclast generation and survival
RANKL is found on what
osteoblast and marrow stroma cells
M-CSF is secreted by what
osteoblast
MCSF receptor is found on what and allows for what
osteoclast
allows for osteoclast generation and survival
WNT is secreted from what
marrow stromal cells
LRP5 and LRP6 are found on what and bind what and do what
osteoblast
bind WNT protein
activate beta-catenin
secrete osteoprotegrin (OPG)
what does osteoprotegrin (OPG) do
blocks RANK
from what and when is osteoprotegrin (OPG) secreted
from osteoblasts when WNT has bound LRP5 and LRP6
the organic matrix of bone composition is mostly made up of what
Type 1 collagen
what are the types of bone
woven bone (random collagen deposition) lamellar bone (ordered collagen deposition)
what are the types of lamellar bone
compact bone spongy bone (calcinous)
levels of what parallel osteoblast activity
osteopontin (osteocalcin)
unique to bone
alkaline phosphatase is secreted from what
osteoblasts
osteopontin activity is high in what
growing kids
what type of bone resists forces in all directions
woven bone
what bone has rapid growth and is found in healing fracture
woven bone
woven bone in an adult is what
pathologic
what is intramembranous ossification
bone formation direct form mesenchyme
appositional growth
what is dysostosis
local problems in migration of mesenchyme and their condensation
dysplasia is what
global defect in regulation of skeletal organogenesis
all bones are affected
cleidocranial dysplasia has what pattern of inheritance and the defect
autosomal dominant
RUNX2 (CBFA1) transcription factor defect
what is seen in cleidocranial dysplasia
short stature
abdominal clavicles
supernumerary teeth
Wormian bone
Wormian bone is found in what
cleidocranial dysplasia
achondroplaisa is a defect in what and has what inheritance pattern
FGFR3 point mutation- gain of function that inhibits cartilage growth
autosomal dominant
most common from paternal allele
achondroplaisa is what type of defect
growth plate defect from paracrine cell defect
what is seen in achondroplasia
short stature short proximal limbs normal trunk length enlarged head with building forehead depression root of nose normal longevity, intelligence, and reproductive status
what is the defect in thanatophoric dwarfism is a defect in what
FGFR3 mutation- gain of function
what is seen in thanantophoric dwarfism
cloverleaf skull micromelic short bowed limbs frontal bossing with macrocephaly small underdeveloped chest with bell-shaped abdomen diminished chondrocyte proliferation
a gain of function in LRP5 is seen in what, with what inheritance pattern, and what happens
Osteopetrosis Type 1
autosomal dominant
cannot up regulate osteoclasts
Osteoporosis pseudoglioma syndrome is due to what
inactive LRP5
what is seen in osteoporosis pseudoglioma syndrome
skeletal fragility
loss of vision
what is “marble bone disease”
osteopetrosis
osteopetrosis is due to what
reduced osteoclast bone resorption:
cannot acidly pit (carbonic anhydrase II (CA2) deficiency
defect in RANKL
LRP5 gain of function
erlenmeyer flask deformity (bulbous long bones) is seen in what
osteopetrosis
what is seen in osteopetrosis
bone deposition replaces medullary cavity (extra medullary hematopoiesis)
bulbous long bones (erlenmeyer flask deformity)
narrow neural foramina
brittle bones
what is the spectrum of osteopetrosis
autosomal dominant benign to autosomal recessive “malignant”
osteogenesis imperfecta aka brittle bone disease is due to what
Type 1 collagen
mutation of alpha1 or alpha 2 chains
Osteogenesis Imperfecta Type I is what inheritance pattern and what is seen
autosomal dominant
normal stature with less fractures after puberty
blue sclerae from translucency of sclera
hearing loss
dentinogenesis imperfect from dentin defect
osteoporosis is what
increased bone porosity and decreased mass
what causes primary metabolic bone disease
senile
postmenopausal
idiopathic
what in menopause leads to osteoporosis
increased expression of RANK, RANKL
secondary metabolic bone disease is caused by what
drugs diabetes endocrine disorders malignancy liver GI disease
what is the difference b.w osteopenia and osteoporosis
osteopenia- decrease bone mass
osteoporosis- osteopenia to the point of risk of fracture
what is the low turnover variant of osteoporosis
senile osteoporosis
what is the high turnover variant of osteoporosis
postmenopausal osteoporosis
postmenopausal osteoporosis is caused by what
decreased estrogen leads to increased inflammatory cytokines
this increases RANKL and decreases OPG
osteoclast activity increases more than osteoblast
how do you detect osteoporosis
Dual-energy absorptiometry
in osteoporosis the cortex of the bone resembles what
cancellous bone
