1 - Physiological Changes Of Aging Flashcards
Older adults: def
Age > 65y
Subdivisions of older adult pop: 3 categories, age & characteristics of each
Young old: 65-74y, Recently retired people, quite active (babysitting grand children, continue working for ≠ reasons)
Mid old: 75-84y, Many may rest during day. Experience more age related change
Old old: over 85y, Many may rest during day. Experience more age related change
3 changes between 3 subdivisions
- Number of hospitalization increases with age (internal medicine & orthopedics)
- Hospitalization length increases
- Mortality rate increases
Aging def & characteristics
= progressive deterioration of functional properties of body at cellular, tissue & organ levels
- Related changes are normal & vary with each individual
- Most visible signs of aging: grey hairs, postural changes (increased flexion), muscle mass,loss & wrinkles
Why important to understand physiological changes
- Promoting healthy aging
- Developing effective healthcare plans
- Improvement of quality of life
- Reducing cost of healthcare
Physiological changes of aging
- Cardiovascular change
- Nervous system
- Gastrointestinal changes
- Skin changes
- Immune system changes
- Endocrine system
- MSK system
- Thermoregulation control changes
Skeletal muscle consists of:
- Type I aerobic, slow twitch
- Type IIa aerobic, fast twitch
- Type IIb anaerobic, fast twitch
Body composition changes
- Normal aging results in muscle mass loss, which starts in 4th decade (after age of 30) of life & advance with age
- ≈ 3-8% loss / decade
- > 60s, loss / year is 3%
- Muscle strength declines by 10% to 15% per decade
Muscle & aging
Loss of muscle mass & strength
- Increased percentage of type I fibers
- Decreased size & number of type II fibers
- Metabolic consequences (high % of fat, decreased protein synthesis) - Muscle fibers denervation
In general, aging associated with greater decline in lower body than upper body & extensors compared with flexors strength
Changes & effects of MSK system
Tableau
From which decade & how many % decline muscle mass
Which type of fibers most lost
3rd to 8th, 30%
Mainly loss of type II muscle fibers resulting in reduced force contraction
Connective tissue & aging
- Skin collagen & elastin synthesis declines
- Fibers get thicker
- Increased proteolytic of connective tissue
- Elasticity off skin affected
Skin & aging: changes & effects
Tableau
Clinical relevance of MSK system changes
- Patients prone to cuts & bruises by grazing equipment in gym setting.. (parallel bars because skin so fragile)
- Patients predisposed to pressure sores
- Less pain reported due to decrease sensitivity (unaware of cuts & bruises)
- Slower healing due to decreased circulation
- Purple bruises under skin following minor trauma
Articular cartilage & aging
- Joint cartilage = cartilage cells embedded in fibrous collagen matrix & water-proteoglycan (proteins) gel
- Aging: reduced proteoglycans, become shorter, loses ability to hold water
- Effect: degeneration, thinking/damage & loss of water content in articular cartilage leads to OA
Summary changes & effects of skeletal system
Tableau
Nervous systems: effects of aging
- Aging associated with many neuro conditions (Dementia, Parkinson’s disease..)
- Brain’s capacity to transmit & communicate signals reduces
Memory, learning & intelligence changes
- Memory performance —> decreased retrieval ability - Cognition decline: observed around 60s
- Cognitive speed (speed n which person understand & react to info) * Cognitive flexibility (ability to adapt to new situations)
Neurons atrophy
- Decreased size & number of dendrites, decreased connections —> declined reception of information
- Decreased blood flow in brain
- Brain starts to shrink after 40 y.o
Synaptic change
- Changes in number of strength of connection, speed & efficiency of info can be affected
Neurotransmitter changes
- Changes in production, release & reception of neurotransmitters such as serotonin, acetylcholine
- Decreased memory
- Declined perceptual motor skills (timed tasks)
Myelin degeneration
- Slower nerve conduction / slower signal transmission —> reduced coordination & speed processing
- Reduced neuroplasticity —> difficulties with adaptation & new info
- Cellular damage & cell death contributing to neuro diseases & memory / cognition loss
Peripheral nervous system
- Motor, sensory & autonomic fibers lost
- Reduced both afferent & efferent conduction velocity
- Reduced number of innervated muscle cells —> muscle atrophy & denervation
Autonomic nervous system
- Increased activity of sympathetic nervous system resulting in increase systemic vascular resistance & increased arterial blood pressure
