Week 10: Skeletal System Response to Exercise

what is bone remodelling

the continual process of bone breakdown (resorption) and formation (deposition)

what is Wolfe’s Law

Bone forms in areas of stress and is resorbed in areas of non-stress

what elements do the bones store?

calcium and phosphorus

what happens if a person isnot able to get enough calcium from their diet or unable to absorb

bone breaks down to maintain blood calcium levels

how do the kidneys regulate blood calcium levels

filtration and reabsorption rates

whats cortical bone and trabecular bone

cortical- hard

trabecular- spongy

three steps of bone development

Growth

• appositional : thickness/mass

• longtiduinal: length @ epi plate

modelling

• ensures appropriate shape, esp during growth

remodelling

occurs in response t ostress

• osteoclasts; causes resorption

• osteoblasts; causes deposition , ossification

• osteocytes; mature osteoblasts; initiates calcification

Vitamin D ( calcitionin) impact on bone remodelling

stimulis for release: increased blood ca levels

effect on bone; deposition (increases calcium)

effect on blood ca: decreased

Parathyroid hormone impact on bone

stimulus; increased blood ca levels

effect on bone: bone resorption (decreased calcium)

blood ca: increases

what does vitamin D due to ca in intestines

increases its abosprtion and increases blood ca levels

what are estrogen, testerone and growth hormone role in bones

stiulate bone growth and eventual epiphesiyal plate closure

what is mechanotransduction (exercise effect)

process by which bone responds to mechanical force on it

• compression and tensille forces

explain what happens in bones while weight bearing or exercise

1. hydrostatic pressure, causing movement of fluid

2. triggers osteogenic response, building new bone

what is mechanostat thoery

process by which bone responds to mechanical forces placed on them

whats minimal effective strain

higher MES required for overload

adaptations to bone with exercise

• speceficity; weight bearing

• overload: MES above daily activities for increase BMD

• Rest/recovery, individualization, maintenance,r eversibility