Arthritis Flashcards
what is bone made of
a calcified extracellular matrix (ECM)
made of inorganic ions
what are osteoblasts
make bone by secreting collagen and calcium salts
what is an osteocyte
derived from osteoblasts and sits in a small chamber called a lacuna
it maintains the bone
what are osteoprogenitor cells
stem cells in the bone that make new osteoblasts as osteoblasts cant divide into new ones
what are osteoclasts
bone resorption
they come from white blood cells
osteoclasts cause proteolytic enzymes and hydrochloric acid to resorb bone
what is bone homeostasis
this means that there is no net gain or loss of bone
what are the different types of bone that are laid down
- first woven bone/immature bone
- secondary bone is split into:
-cortical/lamellar- dense, compact
-cancellous- spongy- this is below the roots of teeth
how does vitamin D relate to bone formation
vitamin D increases calcium and phosphate
vitamin D comes from sunlight or diet e.g. fish
vit D increases the uptake of calcium in the small intestine
what are rickets
curved legs from vit D deficiency
what does the parathyroid gland do
secretes the parathyroid hormone(PTH) which increases calcium and phosphate in the blood by promoting the kidneys to make vit D and reabsorb calcium into the blood
what are the 2 types of thyroid gland malfunctions
- primary hyperparathyroidism
- secondary hyperparathyroidism
what is primary hyperparathyroidism
increased parathyroid hormone levels
often due to an adenoma (benign tumouor)
what does secondary hyperthyroidism do
-it causes calcium salts in CKD chronic kidney disease
- it compensates for this the parathyroid gland secretes more parathyroid hormone
- it increases bone resorption
- it leads to renal osteodystrophy (when the kidneys cant maintain calcium and phosphate levels )
how does hyperparathyroidism affect the jaws
very rare but can present as central giant cell granuloma
if a pt has this alongside hyperthyroidism it is termed- brown tumour of hyperparathyroidism
what are the stages of bone fractures
- the early infalmmatory stage
- the repair stage
- the remodelling stage
what does the early inflammatory phase of bone fractures consist of
- bleeding occurs at the fracture site and forms a hematoma (blood clot)
- inflammatory cells and fibroblasts infiltrate the site - TNF (tumour necrosis factor) alpha, IL1,6,10,12, TGF (transforming growth factor)
- blood vessels go into the hematoma and granulation tissue forms
-
what does the repair stage of bone fractures consist of
-the granulation tissue formed in the inflammatory stage turns to callus
- primary callus turns to secondary callus by endochondral ossification
- osteoids are secreted into the area forming new bone
cartilage calcified due to BMPs, TGF-betas, IGFs, osteocalcin, collagen I, V and XI
- collagen forms in the area forming new bone
what does the remodelling stage of bone fractures consist of
redistribute compact and oven bone
orgnised osteoblastic and osteoclastic activity coordinates remodelling