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

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2
Q

Rate of aging

A

-Occurs at different rates among individuals and within individuals -> generally does not cause symptoms

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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
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4
Q

“Successful” aging (4)

A
  • Freedom from disease
  • freedom from disability
  • intact mental capacity
  • active engagement with life

these are very subjective

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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”
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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

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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

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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
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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)

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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
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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
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12
Q

Osteoarthiritis -> where it is most likely to occur (2)

A

-occurs in weigh bearing joints and areas of repeated strain

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13
Q

4 types of joint diseases

A
  • neuromechanical (e.g. osteoarthritis)
  • Inflammatory (e.g. septic arthritis)
  • Immune (rhueumatoid arthritis)
  • Metabolic (gout)
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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
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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
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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