Aging and Death Flashcards
Definition of Aging and Senescence
-also the 3 aspects of aging
- Aging: all the changes occurring in the body with the passage of time
e. g. growth, development
- they are progressive changes from birth to infancy - Senescence: the degeneration that occurs in the organ systems after the age of peak functional efficiency
- gradual loss of capacities, to repair and increased susceptibility to disease
*are physical, psychological and social aspects of aging
Rate of aging
-Occurs at different rates among individuals and within individuals -> generally does not cause symptoms
Characteristics of Mammalian Aging (4)
-What influences aging (4)
- cellular and physiological deterioration
- increased mortality with age following maturation
- increased vulnerability to disease
- decreased ability to adapt to stress
- i.e. impaired homeostasis
Influenced by;
- Genetics
- Lifestyle
- Physiological
- Socioeconomics
“Successful” aging (4)
- Freedom from disease
- freedom from disability
- intact mental capacity
- active engagement with life
these are very subjective
- chronological age
- Social roles and age
- Functional age
- Subjective age
- Chronological age is a common marker of old age
- Social roles and age usually guide the expectations or guidelines for people who occupy given positions (i.e. grandmother typically thought of as an old woman)
- Functional age: what you can do and how you look
- Subjective age: those who compensate for limitations of functional age maintain a subjective age
- “you’re only as young/old as you feel”
Senescence
- what medical research is focusing on
- how senescence typically works
- what can lessen the effects
- Australia is an aging nation
- Most medical attention = prevention and treatment of the diseases of age
- Senescence of one organ typically leads to senescence of another organ system (flow on effect)
- organ systems do not degenerate at the same rate
-Personal health and fitness practices can lessen the effects of senescence
Senescence of the skin
- Features of aging skin
- photoaging
- thickness of skin
- Skin = first protective layer - gets exposed to elements, chemicals, damaging radiation etc.
- usually occurs around 40s
- Features of aging skin;
- gray, thinning dry hair
- paper thin, loose skin that sags (due to loss of elastin)
- dry skin that bruises easily and heals slowly
- rosacea - patchy networks of tiny, dilated vessels visible on nose and cheeks
- hypothermia in cold weather and heat stroke in hot weather
- atrophy of cutaneous vessels, sweat glands and subcutaneous fat
- decreasaed vitamin D production causing calcium deficiency
- Photoaging = degeneration in proportion to UV exposure -> skin spots, skin cancer, wrinkling
-Skin becomes thin due to slower turnover of cells
Body Composition over time
-fat, cell mass and bone
- More fat in certain places
- decreased cell mass; lose supporting cells
- Bone mass also decreases
Stature
- height: lose 1 cm every 10 years after the age of 40
- less bone mass and a decrease of cartilage turnover
-also, invertebral discs become drier and lose fluid (therefore shortening)
Skeletal system -> aging
-osteopenia
- osteoporosis
- differences between men and women
- Osteopenia: loss of bone mass
- Osteoporosis: loss is severe enough to compromise a person’s physical activity and health (unable to maintain bone)
- after 30, osteoblasts less active than osteocytes
- after 40, women lose 8% bone mass per decade, men lose 3%
- estrogen has a protective feature for bone loss - why women lose more
Skeletal system -> aging
- joint diseases
- synovial fluid
- sternocostal joints
- intervertebral discs
- many types of joint diseases
- synovial fluid less abundant and articular cartilage thinner or absent - produces friction that causes pain
- breathing difficult due to calcification of sternocostal joints
- degeneration of intervertebral discs = back pain and stiffness
- herniated discs less common
Osteoarthiritis -> where it is most likely to occur (2)
-occurs in weigh bearing joints and areas of repeated strain
4 types of joint diseases
- neuromechanical (e.g. osteoarthritis)
- Inflammatory (e.g. septic arthritis)
- Immune (rhueumatoid arthritis)
- Metabolic (gout)
Muscular System -> aging
- 30% loss of muscle between 30-80
- muscular atrophy causes replacement of lean body mass (muscle) with fat
- muscle strength peaks at 20
- fast-twitch fibres exhibit earliest and most severe atrophy
- Loss of strength
Nervous system and aging
- features of cerebral and neuronal atrophy
- what features suffer most (3)
- effect on autonomous nervous system (what this means)
- Cerebral and neuronal atrophy
- peak development around age 30
- from age 35, 100 000 brain cells die every day
- brain weighs 56% less by age 75
- Cortex thins, gyri narrow, sulci widen
- fewer synapses and neuroglia
- less neurotransmitter and receptors
- degeneration of myelin = slower signal
- motor co-ordination, intellectual function and short term memory suffer most
- autonomic nervous system is less efficient at regulating body temp and blood pressure