Aging and Death Flashcards
1
Q
Definition of Aging and Senescence
-also the 3 aspects of aging
A
- 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
2
Q
Rate of aging
A
-Occurs at different rates among individuals and within individuals -> generally does not cause symptoms
3
Q
Characteristics of Mammalian Aging (4)
-What influences aging (4)
A
- 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
4
Q
“Successful” aging (4)
A
- Freedom from disease
- freedom from disability
- intact mental capacity
- active engagement with life
these are very subjective
5
Q
- chronological age
- Social roles and age
- Functional age
- Subjective age
A
- 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”
6
Q
Senescence
- what medical research is focusing on
- how senescence typically works
- what can lessen the effects
A
- 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
7
Q
Senescence of the skin
- Features of aging skin
- photoaging
- thickness of skin
A
- 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
8
Q
Body Composition over time
-fat, cell mass and bone
A
- More fat in certain places
- decreased cell mass; lose supporting cells
- Bone mass also decreases
9
Q
Stature
A
- 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)
10
Q
Skeletal system -> aging
-osteopenia
- osteoporosis
- differences between men and women
A
- 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
11
Q
Skeletal system -> aging
- joint diseases
- synovial fluid
- sternocostal joints
- intervertebral discs
A
- 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
12
Q
Osteoarthiritis -> where it is most likely to occur (2)
A
-occurs in weigh bearing joints and areas of repeated strain
13
Q
4 types of joint diseases
A
- neuromechanical (e.g. osteoarthritis)
- Inflammatory (e.g. septic arthritis)
- Immune (rhueumatoid arthritis)
- Metabolic (gout)
14
Q
Muscular System -> aging
A
- 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
15
Q
Nervous system and aging
- features of cerebral and neuronal atrophy
- what features suffer most (3)
- effect on autonomous nervous system (what this means)
A
- 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
16
Q
Age on Sense organs: Vision
A
- night vision impaired -> fewer receptors, pupil dilators atrophy and enzymatic reactions become slower
- loss of flexibility of lens
- cataracts or cloudiness of lenses
- glaucoma risks increase (fluid in anterior of eye that causes pressure to build up)
17
Q
Age on Sense organs; Hearing
A
- tymphanic membrane and ossicle joints stiffen (can’t vibrate as much)
- hair cells & auditory nerve fibres die
- death of receptor cells result in dizziness
- taste and smell is blunted as receptors decline
18
Q
Endocrine system
- how it degenerates over time
- Pituitary gland
- type 2 diabetes - why more common
A
- Degenerates less than any other system
- only reproductive, growth and thyroid hormones decline steadily after adolescence
- other hormones secreted at fairly stable rate
- pituitary gland less sensitive to negative feedback inhibition by adrenal glucocorticoids
- response to stress is prolonged - type 2 diabetes is more common (more body fat decreases insulin sensitivity of other cells)
19
Q
Circulatory System
-3 things that may occur
A
- Fat can build up between layers of blood vessels (tunica media, intima and adventitia) and can block blood flow
- varicose veins due to weaker valves
- anemia may result from nutrition, lack of exercise, changes in erythropoiesis, lack of intrinsic factor which reduces vitamin B12 absorption increasing risk of pernicious anemia
20
Q
Immune system and aging
A
- Amounts of lymphatic tissues and red bone marrow decline
- fewer hemopoietic stem cells, disease-fighting leukocytes and antigen-presenting cells
- lymphocytes fail to mature
- both types of immune responses are less efficient
21
Q
Respiratory system and aging
A
- Declining pulmonary ventilation
- less flexible coastal cartilages
- lungs have less elastic tissue and fewer alveoli
- elderly less able to clear lungs of irritants and pathogens
- therefore more susceptible to respiratory infection and pneumonia
- chronic obstructive pulmonary diseases
- emphysema (damage w/in airsacs) and chronic bronchitis more common
22
Q
Urinary System and aging
A
- Renal atrophy - 20-40% smaller by age 90
- loss of nephrons and atherosclerotic glomeruli
- filtration rate decreases leaving little reserve capacity (can’t clear drugs as rapidly)
- fluid balance less responsive to hormone and sense of thirst sharply reduced
- voiding and bladder control
23
Q
Digestive system and nutrition
A
- dental health affected by reduced saliva
- gastric mucosa atrophies and secretes less acid and intrinsic factor
- intestinal motility decreased due to weaker muscle tone, less fibre, water and exercise
- reduced food intake due to loss of appetite and mobility risks malnutrition
- also due to loss of taste buds
24
Q
Reproductive system and aging
-males vs. females
A
- Males; gradual decline in testosterone secretion, sperm count and libido
- fertile into old age but impotence may occur
- Females; more abrupt, rapid changes due to menopause
- ovarian follicles used up, gametogenesis ceases and ovaries cease production of sex steroids
- also an elevated risk of osteoporosis and atherosclerosis
25
Q
Exercise and Senescence
A
- Good nutrition and exercise are best ways to slow aging
- exercise provides endurance, strength and joint mobility
- also reduces incidence/severity or hypertension, osteoporosis, obesity and diabetes mellitus
- resistance exercise also reduces bone fractures
- endurance reduces body fat and increases cardiac output and oxygen uptake
26
Q
Mechanisms of Senescence (theories)
- Replicative senescence
- Cross-link theory
- protein abnormalities
- free radical theory
- autoimmune theory
A
- Replicative senesecence: decline in mitotic potential with age -> human less have finite no. of cell divisions
- Cross-link theory: 1/4 of body = collagen; over time collage molecules become cross-linked making fibres less soluble and stiff
- Protein abnormalities: Increasingly abnormal structure in older tissues and cells accumulate over time
- Free radical theory: free radicals have destructive effect on macromolecules
- molecules damaged by free radicals are long-lived and accumulate within cell
- Autoimmune theory: altered macromolecules recognized as foreign
- lymphocytes stimulated to attack own tissue
27
Q
Evolution and senescence
A
- thought that death occurred for good of species -> leaves resources available for young and healthy
- natural selection wouldn’t occur on genes that only affect elderly -> is why aging genes remain with us today
28
Q
Australian Life
- average lifespan
- oldest age ever achieved
A
- Average lifespan for;
- Australian boy = 79.9 yrs
- Australian girl = 84.3 yrs
- maximum age reached by human = 122 yrs
29
Q
Biological death
-2 ways it can be classified
A
- Clinical death: when someone stops breathing
- Biological death: brain cells die due to lack of oxygen
- no definable instant of death
- some organs function for an hour after heart stops
- usually occurs as failure of particular organ followed by a cascade of other organ failures
