Week 6- Musculoskeletal Flashcards
Osteoblasts
Build bone calcium phosphate
Osteoclasts
Dissolve calcium phosphate
Osteocytes
Pressure sensor
Hypocalcaemia
Low (ionised calcium)
Hypercalcaemia
High (ionised calcium)
Parathyroid hormone
Main regulator of plasma calcium
Secreted by parathyroid glands
^ when plasma calcium decreases
3 actions:
^ calcium resorption from bone
^ calcium absorption by kidneys
^ production of calcitriol
Calcitriol (vitamin D)
Formed in kidney Formation stimulated by low plasma calcium and PTH Supports PTH action - increases absorption of calcium in gut - supports PTH . Calcium resorption from bone . Calcium reabsorption by kidneys
Factors which increase bone density
Preproduction hormones (oestrogen, testosterone)
Strain on joins ( physical exercises increases density)
Calcium balance ( calcium in diet, vitamin D)
Bisphosphonates
Infested on empty stomach
Inhibit osteoclasts activity
Persistent effect
Risk : gastric irritation (ulcers)
Treatments for osteoporosis
Early: calcium, vitamin D
Later(Ys<2.5): bisphosphonates,
anti-RANK-L antibody(denosumab),
oestrogen receptor modulators
Anti-RANK-L antibody ( denosumab)
Injected every 6 months
Inhibit osteoclast formation
Risk: injection site irritation
Effects short term
Oestrogen receptor modulators
Promote oestrogen like effects
Reduced cancer risk vs oestrogen
Contraindication with cardiovascular risk