week 3: osteoporosis

Question 1

when is peak bone mass?
what factoprs influence bone mass?

Answer 1

peak
- 16-25 years

influences
- genetics
- hormal factors
- excercise and enviomental factors
- nutritional factors

Question 2

what are the fucntions of bone turnover?

Answer 2

repair microfractures (in cortical bone)
adjust strength according to mechanical stress
- high strain
- unusual strain
- unusual rate
maintaining mineral homeostasis

3 main:
REPAIR
ADAPT
MAINTAIN

Question 3

what are osteocytes

Answer 3

resident ‘fixed’ osteoblasts

Question 4

describe the process of resorbtion and deposition

Answer 4

• it is tirggered by enviroment, again, loading, menopause
• osteoclasts form resorbtion pits: releasing chemical mediators that induce osteoblast activity, deposition of collagen, and formation of new bone

Question 5

define osteoporosis

Answer 5

A condition in which bones become weak and brittle

Question 6

how does osteoporosis occur

Answer 6

• when the balance between resorbtion and deposition is lost/imblanced
• leads to increased porosity of bones, and fracture risk

eg:
- resorbed cavity is too large
- newly formed bone is too small
- increased number of remodelling units
- formation is less than resorbtion

Question 7

where does osteoporosis occur?

Answer 7

trabecular bone:
forms 20% of skeletal mass
contibutes to 80% of bone turnover
large SA/is superficial

cortical bone:
forms 80% of skeletal mass
contribute to 20% of bone turnover
lesser SA/is deep

• osteoporosis occurs in trabecular bone becuase it has a large SA and is easier to target becuase is on surface of bone
• also becuase osteoclasts/blasts are on the surface of bone

Question 8

types of osteoporosis

Answer 8

primary:
- affects both genders
- bone loss that we see with aging
- when dietary calcium, vit D, plasma calcium, bone formation, and eostrogen deficiency decreases

secondary:
- sharp drop of eostrogen from 50-60 in women due to menopause
- associated with cytokine levels
- causes an increase in osteoclast activity and decrease in osteoblast lifetime
- decreased calcium resorbtion is also associated with estrogen reduction

Question 9

what leads to an osteoportic fracture?

Answer 9

• low peak bone mass
• post menopausal bone loss
• age-related bone loss
• other etc.
• 33% of people in 80s die within 12 month of osteoporitic fracture

Question 10

what can physios do to help osteoporosis?

Answer 10

• increase calcium intake becuase a decrease stimmulates parathyroids release of PTH, which strips bone of minerals, leading to bone mass decreasing
• Vitamin D becuase it is esstial for calcium absorbtion
• (refer to dietician)
• increase excercise (loaded, balance, strength)
• increase healthy lifestyle/ promotion

Question 11

pharma considerations

Answer 11

• calcium supplements
• vit D analougues
• oestrogen/progestin therapy

bone specific therapy (takes years)
- biophosphates (improve mineral density)
- strontium ranelate (reverses resorbtion)
- raloxfiene (increase bone density for post-menopausal women)