Aging Flashcards
Characteristics of young bone
reduced mineralization
less stiff
bendier
increased work to fracture
Bone mineral density and work to fracture as we age
Bone mineral density inc to 20’s then dec
Work to fracture dec (becomes easier to break) as age
Greenstick fracture
crack fails to propagate (not a clean break across bone)
Torus
peds fracture caused by compression, bone buckles
bone deformed, but does not break
Plastic deformation
bone prematurely bends, but no fracture
peds fracture
Salter-Harris fracture
growth plate fractures
can be difficult to diagnose
peds fracture
Aging
group of processes occurring in living organisms that with the passage of time lead to a loss of adaptability, functional impairment, and death
Diff forms of aging
aging with disease and disability
usual aging: absence of pathology, but decline in function
ideal healthy aging: no pathology or functional loss
Theories of aging
cell senescence
telomere shortening
free radical damage
THERE IS DISRUPTION OF HOMEOSTASIS
Frailty
wasting syndrome characterized by excessive vulnerability to stressors and the inability to regain homeostasis after a destabilizing event
Clinical manifestations of frailty
unintentional wt loss
self-reported exhaustion
muscle weakness
slow walking speed
Poor outcomes associated with frailty
increased risk of falls worsening mobility greater difficulty in performing activities of daily life hospitalization death
Posture aging
Increased thoracic kyphosis Decreased lumbar lordosis Pelvis tilts posteriorly Forward head, rounded shoulders flexed hips and knees reduced flexibility in gastrocnemius and soleus POSTURAL CHANGES INC RISK OF FALLS
Physical changes of musculoskeletal sys
loss of muscle mass
dec bone mineral mass/density
cartilage lose elasticity/calcify
tendons and lig lose elasticity
delayed response times (dec proprioception)
reduced joint range of motion and flexibility
Sarcopenia
loss of muscle mass due to loss of muscle fibers (hypoplasia) and reduced muscle cross-sectional area (atrophy)
fewer and weaker cross-bridges b/w actin and myosin
dec in number of motor units and motor neurons (especially type II fibers) –> less fine scaled control over muscle force
loss of platicity in muscle firing freq, EMG amplitude and force output
Loss of myosatellite (muscle SC), limiting potential for muscle to regenerate after injury
How does adipose/muscle change as we age?
Adipose replaces muscle tissue
How does number of slow/fast fibers change as age?
Babies have many fast (II) fibers
as age, II dec and I inc
Causes of sarcopenia
hormone changes (estrogen, androgen, growth hormone) inc production of inflammatory markers/catabolic cytokines dec O2 delivery/utilizaiton neural factors (denervation of motor units) inactivity, energy intake, nutrition
Consequences of sarcopenia
lose muscle strength, power, educrance
reduced ADLs
changes in balance and gait –> falls
metabolic changes (dec –> causes obesity)
Change in osteoblast/clast as age?
Causes?
blast dec
clast unchanged
low horomones
poor Ca, vit D
inactivity
diet, cigarettes, alcohol
Change in cartilage as age
decreased water content
osteoarthritis (NOT RA)
Causes of osteoporosis
low estrogen after menopause
low testosterone
white and asian women more likely
Contributing factors of osteoporosis
inactivity -- bed rest corticosteroid meds (prednisone) hyperparathyroidism (inc osteoclasts) low vit D alcohol consumption family history hormone cancer treatment low body wt smoking low Ca
Osteoporosis treatment
diet physical activity stop smoking, alcohol Anti-resorptive agents (inhibit osteoclasts) --estrogen replacement --biphosphonates Anabolic agents (promote osteoblasts) --PTH Reduce risk of falls
Osteoarthritis
most commonly affects hand joints
complaints more often focused on lower limb joints
cartilage breaks down and wears away – bones rub together
–hypertrophy of subchondral bone
disorder of diarthroidal joints
caused by wear and tear
most common joint disease
Contributing factors to OA
age family history obesity (lower limb OQ) fractures/joint injuries -- meniscal tears or ACL injuries Long-term overuse at work or in sports
Diagnose OA from radiograph
decreased joint space
osteophytes
One cause for successful aging
calorie restriction
inc fruit and veg
1-7 alcoholic drinks per week (anti-inflammatory)
exercise
Cicumferential growth (apposition)
occurs via membranous ossification at the periosteal boundary
