Path - Bones Flashcards
function of osteoblasts
synthesize, transport, and assemble matrix
regulate mineralization
compare osteocytes and osteoblasts
osteocytes are inactive osteoblasts with less cytoplasm
what bone cells have canaliculi and what do they use them for
osteocytes
use them as tunnels that the osteocyte dendritic processes use to network
describe the chemicals associated with building bone and those with breaking down bone
build: estrogen, testosterone, vitamin D
breakdown: PTH, IL-1, glucocorticods
define dysostosis and what genes it is related to
migration and condensation of mesenchyme and differentiation into cartilage anlage
associated with homeobox genes
define syndactyly/craniosynostosis
abnormal fusion of bone
is dysplasia of bone pre-malignant?
no
what are the differences between OI type 3 and 4
type 3:
- fractures present at birth
- short stature
- blue, purple, grey sclera
- loose joints and poor muscle development
- more definitive spinal curvature
- often severe bone deformity
type 4:
- fractures mostly before puberty
- shorter than average
- white/near white sclera
- tendency towards spinal curvature
what are the similarities between OI type 3 and 4
- improperly formed collagen
- barrel-shaped rib cage
- triangular face
- brittle teeth possible
- hearing loss possible
mutation in CLCN7 indicates
osteopetrosis (marble bone dz, albers-schonerg dz)
CA2 deficiency indicates
osteopetrosis (marble bone dz, albers-schonerg dz)
bones that lack a medullary cavity indicate
osteopetrosis (marble bone dz, albers-schonerg dz)
erlenmeyer flask bone findings on x-ray indicate
osteopetrosis (marble bone dz, albers-schonerg dz)
optic atrophy, deafness, and facial paralysis cranial nerve deficits are indicative of what bone dz
osteopetrosis (marble bone dz, albers-schonerg dz)
defects in acid hydrolase enzymes are associated with what disease group
mucopolysaccharidoses
what happens to the bone in mucopolysaccharidoses
chondrocytes degrade ECM mucopolysaccharides –> mucopolysaccharides accumulate in chondrocytes in the extracellular space –> structural defects in articular cartilage
clinical presentation of a patient with mucopolysaccharidoses
short stature, chest wall abnormalities, malformed bones
atraumatic or vertebral compression fracture indicates
osteoporosis
what genetic factors are associated with osteoporosis
LRP5 single gene defect
also RANKL, OPG, RANK, HLA, estrogen receptor gene, vitamin D receptor gene
demo: caucasian with light colored hair and eyes
what treatment for breast cancer has been associated with osteoporosis
tamoxifen
what are some secondary causes for osteoporosis
renal or hepatic failure, hyperthyroidism
SQSTM1 gene mutation is associated with what dz
sporadic paget disease
not familial
“cotton wool” finding on x-ray indicates what dz
paget dz
what types of fractures occur in paget dz
chalk-stick type fx of long bones of legs
leontiasis ossea (lion face) and platybasia (invagination of skull base) are associated with what dz process
paget dz
bowing out of lower limbs with increased warmth and tenderness over the bones indicates what dz
paget dz
compare rickets and osteomalacia
both vitamin D deficiency or abnormal metabolism of vitamin D
Rickets: children, interferes with deposition of bone in the growth plate
osteomalacia: adults, bone formed during remodeling is under-mineralized –> predisposing to fractures
clinical sx of rickets
- bowed legs
- frontal bossing (large forehead)
- squared off head
- rachitic rosary of ribs
- anterior protrusion of chest (pigeon breast)
- lumbar lordosis
“railroad track” bones indicate what dz
hyperparathyroidism causing dissecting osteitis
why is renal osteodystrophy called the “silent crippler”
the bone changes from renal osteodystrophy can begin many years before sx appear in adults with kidney dz
what is osteonecrosis
infarction of the bone and marrow
compare subchondral and medullary infarcts in osteonecrosis
subchondral: cause pain and are initially associated only with activity, then becomes constant
medullary: usually small and clinically silent
80-90% of osteomyelitis cases are caused by what organism
s. aureus
osteomyelitis in a sickle cell patient is often caused by what organism
salmonella
what is seen on histology in mycobacterial osteomyelitis
caseous necrosis and granulomas
