What is Aging? What are the 2 types of changes/aging?
- It Theoretically, starts from moment of birth and takes place throughout the life span.
- 2 types of changes/aging is
- maturation: from moment of birth to adolescence
What are the types of processes of aging?
- Chronological aging: aging through number of birth years
- Psychological Aging: cognitive functioning and adaptive capacity (slow memory processing, memory loss etc.)
- Biological Aging: efficiency and functional abilities of organ systems
- Sociocultural: how status and roles change (roles and relationships (old people status maintained by wealth and availability of resources)
Why is there an interest in aging? What are some aging issues?
- There is a growing size of older population due to the baby boomer period
- gradual increase of age for those 65 years of age since the 1900.
- In 1990-2000 significant decline due to the age of great depression and the declining birth rate during that time.
- A significant increase of 100% of older population by 2030 is expected.
- Aging issues are retirement, SES, and social services
What are the differences between maximum lifespan and life expectancy?
- Maximum lifespan is the age for any given species to live, ex. humans 120
- Life Expectancy is the avergae number of years of life remaining at birth or any given age. It is determined by location and race ex. In Southern parts of Africa it is low Because high infant mortality rate
What is the UN Criteria of age categories? Which is the oldest group?
- Social context dependent on retirement age
- 85+ = oldest old
- 75-84 = middle old
- 65-74 = young old
What is the US case that people are living longer?
- average life expectancy in US in 1900 was 47 y/o
- in 2008 it was 78 years old
- in 2000, at the age of 65 there was a 17.9 year estimation for people to live longer
Why are people living longer?
- Advances in medicine/healthcare
- Advances in sanitary system
- Eradication of many diseases
- infant and childhood mortality rate decreased Improvement of maternal death
- Influenza and pneumonia control means more people surviving to old age
- people are healthier than before “compression of morbidity”, which means no disease for a long time.
- more people dying of natural death, or wearing out of organs.
What is the typical pattern of demographic transition theory regarding mortality and fertility?
- DTT deals with mortality and fertility rates.
- pre-modern societies have high fertility and mortality rates, which means the the population is low.
- Then when they move to industrialization society they have decrease mortality rates. Mortality decline always comes before
- fertility decline.
- In postmodern society fertility decline then starts to happen and then both mortality and fertility decline, which leads to a
- stabilized population.
- Demographic transition theory deals with
- fertility (giving birth) and mortality (death) rates.
- if mortality rates decline and fertility rates continues to be high then population increase happens.
- If both high population is relatively low Fertility rate low and death rate low – population is stabilized
What is TFR? What is the replacement rate?
- the average number of children a woman would have
- 2 to replace husband and wife and .1 to account for child death
what are example living arrangements for men and women over 65 (in canada)?
- Men are more likely to be married at old age because of Dependency and more money to take on extra spouses
- Woman are more likely to live with relatives because daughters are more likely to live with mothers than fathers and also child caring for grand children
what is the sex ratio and mortality rates btwn male and female
- At birth there is 105 males to 100 females 105: 100, but
- Male babies more likely to die than females due to biological makeup (x-chromosome inactivation)
- females are more likely to live several more years than males
- But male mortality getting better due to medical and technology advancements
what is x-chomosome inactivation?
- responsible for why males have higher mortality rate than female
- happens to females with 2 x-chromosomes
- X chromosome inactivation does not happen to males with only one X
- 8 weeks after fertilization the cell determines which X is activated, either maternal or paternal X, therefore 50% of xchrome is inactivated both paternal and maternal
- in males X chromosome inactivation does not happen, it is purely random and either maternal or paternal x-chrome is inactivated
- ex. hemophilia - inability for blood to clot
- it is located on the x chromosome
- if there is 2 XX and one is inactivated like in females then only 50 percnt of cells have hemophilia traits and the other half does not.
- Males more likely to get affected bc they do not have 2 X’s and if the trait is on a deliterious or harmful X then they will likely be affected
female hormone advantages and disadvantages
- Estrogen is a lubricant for arteries
- Protects artery walls, which lower risk of arteriosclerosis
- estrogen is relatively high
- when menopause is reached estrogen level goes down, then Risk of arteriosclerosis goes up in postmenopausal years
- Iron During reproductive years women have periods and are faced with anemia (iron and oxygen)
- Iron depletion contributes to female longevity Getting rid of iron is good bc too much accumulation of iron in the blood damages membranes, protein, and DNA, which leads to cancer and heart diseases
- But women during reproduction age get rid of iron once a month
- Female live long because hormones are controlled
what is anisogamy? Why it contribute to male mortality?
- Difference in reproductive cells in size or number or form
- deals with reproductive and investment strategies
- male gametes are small and produce more than 1 billion per day
- female gametes: big and limited about 400 eggs during reproductive years
- reproductive strategy is that male can impregnate female faster and are more likely to invest in mating
- females have to carry and nurse and are not heavily invested in reproduction compared to men.
- therefore, there is more likely to be male-male completion and bc of this it leads to higher mortality in males because of violence etc.
What is biological aging? What are some theories of aging?
- Visible signs and internal aging of organs
- Often aging is associated with disease, but it is not a disease
- Aging is a normal process of changes over time in the body and its components
- Common to all organisms
- happens at different rates and from different factors
- mutation accumulation theory
- antagonistic pleiotropy
- disposable soma theory
- wear and tear theory
What are 4 requirements for theories to be viable for normal aging?
- must be universal
- result in physical decline
- be progressive-gradual overtime
- intrinsic - internal factors
- (we must distinguish disease from normal aging: ex. alzheimers, is not really aging it is a type of disease bc its not universal)
what are 2 evolutionary perpective theories of aging?
- Mutation accumulation theory
- Antagonistic pleiotropy
what are 2 organism based theories
- Disposable Soma (evolutionary) Theory
- Wear and Tear theory
what is mutation accumulation theory?
- Accumulated at later age
- Leads to harmful genes selected against through natural selection
- If a harmful gene is expressed early in life it is relatively selected against.
- If the harmful gene starts to be evident after a person already reproduced it is considered a late acting detrimental mutation
- and therefore is more likely to stay in the gene pool and be passed on to next generation
- example: huntingtons disease – expressed between 35-45; by this time many individuals already reproduced. So this disease already passed onto next generation. That’s why it has not been eliminated and stays in gene pool
what is antagonistic pleiotropy theory?
- One single gene has multiple effects (antagonistic means go against each other)
- A single gene can have 2 affects – both bad and good affect.
- it is a Trade off
- Some genes have positive effect in early life, but later in life it becomes harmful
- ex. testosterone gene Promotes reproduction in males in early life (+) Cures injury faster (+), but in Later age it causes prostate cancer (-)
- A beneficial gene will be selected early in life effect early in life, even if it has adverse effects later on
What is disposable soma theory?
How humans allocate energy into certain categories Energy is allocated into reproduction, cell maintenance (and repair), and metabolism In order for us to live metabolism is taken for granted Instead, we divide energy between reproduction and maintenance How much organisms should invest in maintenance and repair? They take a look at How long humans lived in ancestral environment Ideal Survival Curve is about 115-120 y/o Survival curve chart: Stone age: death before 45 Bronze: death before 65?????? Stone and bronze age accounts for If 90% of us die by the age 50, there is little advantage for prolonging long life. Not worth wasting maintenance and repair energy Organisms have evolved…. Good repair and maintenance only for the reasonable chance of survival good for only about 50 years So instead of using this energy for repair and maintenance…spare resources should be used in reproduction Senescence is a result of the accumulation of somatic defects bc body cant??????? But gestating and women? No evidence that gestating women have less system for maintaining and repairing cells Males and females????? Caloric Restriction mice experiment Lifespan of CR of mice….survival of mice with restricted calorie lived longer CR prolongs life, but lowers energy, but the longer calorie is restricted then reproduction stops…CR is effective in prolonging life
What is wear and tear theory?
- the idea that “the organism wears out over time”
- it recognizes maximum lifespan and within this your aging can slow down or speedup
- sometimes explained by using machine analogies: wearing out with use you can replace parts, but cannot repair entirely, and compounded by environmental stress also. machine analogies are not always right because body can Self repair
- ex. Muscle become more efficient with use “if you don’t use it, you will lose it” - the more you use it you become less susceptible to damage
- but does not necessarily mean “the more damage, the more stronger” according to Nosaka and newton who did 8 wk training study
- living too hard and fast cannot expect to live very long