Bone part one Flashcards
What is achondroplasia?
impaired cartilage proliferation in the growth plate
What causes achondroplasia?
auto dom activating mutation in FGFR3
What are the physical deformities in someone with achondroplasia?
most common cause of dwarfism
- short extremities with normal sized head and chest
Why are the head and chest normal in a person with achondroplasia ?
no issue with intramembranous bone formation
What is morquio syndrome?
severe dwarfism, dental defects, mental retardation, corneal opacities
What causes morquio syndrome?
mucopolysach. type IV - deposition of GAGs in long bones
What happens to bones in scurvy?
lack of osteoblastic function
What causes scoliosis and kyphosis?
one portion of the endplate grows faster than the other
What causes osteogenesis imperfecta?
AD defect in collagen type I synthesis
Why do OI patients have blue sclera?
exposure of the choroidal veins
What is osteopetrosis?
inherited defect of bone resorption –> abnormal thick, heavy bone that fractures easily
What causes osteopetrosis?
carb anhydrase II mutation
-need acidic envt for bone resorption
What are some clinical complications of osteopetrosis besides fractures?
anemia, thrombocytopenia, leucopenia
- vision and hearing impairment
- hydrocephalus - thickened foramen magnum
- renal tubular acidosis - carb anhydrase deficient
What is the treatment for osteopetrosis?
BM transplant
What are the steps of bone repair after fracture?
- inflammatory phase: 1-2 days
- 2-5 days after hemorrhage - large clot
- 7 days - earliest bone formed - woven
- reparative phase: first week after -months
- fibroblasts and osteoblasts work from outside to center - remodeling phase - callus seals the end of bones
- may undergo for years
What is myositis ossificans?
reactive bone in muscle after injury
How do you distinguish myositis ossificans from a neoplasm?
bone is mature peripherally and immature in the center
-neoplasms are most mature centrally
what is metastatic calcification?
inc ca and P in the serum leads to deposition
What is dystrophic calcification?
damaged soft tissues are calcified
