1.4 Flashcards
(22 cards)
- What are the main phases of musculoskeletal (MSK) changes through the lifespan?
In early life and adolescence the MSK system grows—with increases in muscle mass and bone density—reaching a peak around 25–30 years, and then enters a gradual decline marked by decreased muscle mass, loss of bone density, and deterioration in joint function.
- How does muscle mass typically change with age?
Muscle mass is maintained at peak levels until around 25–30 years; thereafter, there is an approximate loss of 8% per decade from age 40 to 70, which accelerates to about 15% per decade after age 70.
- What is the typical trajectory of bone density across the lifespan?
Bone density increases during growth to reach peak bone mass in early adulthood, followed by a gradual loss with age that predisposes individuals to conditions like osteoporosis.
- Which hormones act as positive regulators of MSK health?
Testosterone, estradiol (estrogens), progesterone (working synergistically with estrogen), and growth hormone (GH) together with Insulin-Like Growth Factor 1 (IGF-1) promote muscle protein synthesis, bone formation, and overall MSK integrity.
- How does testosterone affect the musculoskeletal system?
Testosterone promotes muscle protein synthesis, reduces muscle protein breakdown, and increases bone mass, thereby supporting overall MSK health.
- What role does estradiol play in maintaining the musculoskeletal system in women?
Estradiol enhances bone formation and bone mass, provides anti-inflammatory protection for joints, and promotes muscle mass, all of which help maintain MSK function.
- How do negative hormonal regulators influence MSK health?
High levels of cortisol—a catabolic hormone—contribute to muscle protein breakdown, reduce bone mass, and promote joint inflammation; in women, certain roles of progesterone may also contribute to bone loss and muscle breakdown.
- How does menopause drive the decline in MSK health?
Menopause leads to a marked drop in estrogen levels, accelerating bone loss, reducing joint and muscle function, and increasing susceptibility to osteoporosis and other MSK-related issues.
- What is mechanobiology and why is it important for musculoskeletal development?
Mechanobiology is the study of how physical forces (from the whole-organism down to the subcellular level) influence biological tissues; in the MSK system, mechanical loading drives bone remodeling, cartilage maintenance, and muscle hypertrophy, ensuring the system adapts to stress.
- How do bones, joints, and muscles typically respond to mechanical load?
When subjected to appropriate mechanical load, bones remodel through osteoblast activity, joints maintain cartilage integrity via chondrocyte-mediated ECM synthesis, and muscles undergo hypertrophy and nuclear addition via satellite cell activation; conversely, lack of load results in atrophy and functional decline.
- What are the main causes of decline in MSK function with age?
The decline in MSK function stems from reduced levels of positive hormones (such as GH, testosterone, and estrogen), increased catabolic effects from cortisol, decreased physical activity, inadequate nutrition, and the cumulative effects of chronic inflammation.
- How does loss of muscle mass (sarcopenia) affect mobility and function in older adults?
Sarcopenia leads to decreased muscle strength and impaired balance, which contribute to reduced mobility, a higher risk of falls, and subsequent fractures, thereby impacting daily functioning and independence.
- What common disorders are associated with age-related MSK decline?
Age-related MSK disorders include osteoporosis, osteoarthritis, and sarcopenia—each of which contributes to chronic pain, reduced mobility, and increased disability.
- How does decreasing bone density increase the risk of fractures in older adults?
As bone density declines, bones become more fragile and less able to withstand mechanical stress, which increases the risk of fractures (e.g., hip, vertebral, and wrist fractures) following falls or minimal trauma.
- What are the consequences of reduced joint function with ageing?
Reduced joint function can lead to chronic joint pain, loss of mobility, stiffness, and arthritis, which in turn diminish the quality of life and the ability to perform daily activities.
- How does MSK decline impact the individual and the community?
At the individual level, MSK decline leads to diminished quality of life, increased disability, and a higher risk of falls and fractures; at the community level, it places a significant economic burden on healthcare systems—illustrated by high treatment costs and loss of productivity.
- Why do lifestyle factors such as diet and exercise play a crucial role in MSK health?
Adequate nutrition (with proper calcium and protein intake) and regular weight-bearing exercise help maintain bone density, muscle mass, and joint integrity, counteracting the natural decline associated with ageing.
- How important is the balance between collagen and hydroxyapatite in bone matrix composition?
The balance is critical: collagen provides elasticity while hydroxyapatite minerals offer rigidity, ensuring that bones have the structural strength to resist both tensile and compressive forces.
- What is the relationship between physical activity and the prevention of MSK decline?
Regular physical activity imposes beneficial mechanical loads that stimulate bone remodeling, cartilage maintenance, and muscle hypertrophy, thereby delaying or mitigating age-related MSK decline.
- How does chronic MSK disability affect healthcare systems economically?
MSK conditions account for a significant portion of healthcare spending, with billions of dollars expended annually (for example, in Australia, costs can exceed $14 billion), highlighting the extensive economic and societal impact of MSK decline.
- In what ways do hormonal changes with age influence the MSK system?
As hormones like GH, IGF-1, and testosterone decline with age—and estrogen drops sharply after menopause—the anabolic support for maintaining muscle, bone, and joint health diminishes, accelerating the degeneration of the MSK system.
- What measures can be taken to help mitigate MSK decline in the ageing population?
Preventative measures include engaging in regular weight-bearing and resistance exercise, maintaining proper nutrition, considering hormone replacement where appropriate, and addressing lifestyle factors such as avoiding smoking and sedentary behaviors.
