Download Final Exam | BIOL 637 - Biology of Aging and more Quizzes Biology in PDF only on Docsity!
Types of Evidence
- Correlational 2. Loss of Function3. Gain of Function TERM 2
Loss of Function
DEFINITION 2 demonstrates necessity; necessary but not sufficientif you remove x, may see a decrease in LS but may be that x-y-LS TERM 3
Gain of Function
DEFINITION 3 add x and see an increase in LSsufficient but not necessary, not the only thing that may be important TERM 4
Age-Related Changes
DEFINITION 4 CPIDcumulative: a number of processes that occur over time to cause aging; increase number progressive: gradual, don't all accumulate instantly intrinsic: not the result of a modifiable environment deleterious: changes that reduce function and inc risk of mortality TERM 5
Aging
DEFINITION 5 a series of CPID changes culminating in death; senescencetime dependent
Biological Aging
functional aging, depends on the underlying physiology TERM 7
Chronological Aging
DEFINITION 7 how much time has passed (calendar) TERM 8
Biomarker
DEFINITION 8 reflection of biological age; there are often correlations between biomarkers and LS *difference between risk factors is that risk factors predict impending death telomeres have become important possible biomarkers TERM 9
What can Survival Curves teach us (tell
us)?
DEFINITION 9 can tell us at any given age, how many people are left, initial population size, longevity and maximum lifespan potential also demonstrates different types of mortality - intrinsic and extrinsic TERM 10
Type 3 Survival
Curve
DEFINITION 10 High Mortality Early - number of surviving decreasing exponentially (lx)- age-specific death rate constant (qx)- lifespan expectation constant (ex)high extrinsic mortality Ex) sea turtles
Ultimate Theories of Aging
answer the questions why does aging exist at all 1. Rate of Living Theory 2. Good of the Species 3. Evolutionary Aging Theory TERM 17
Rate of Living Theory
DEFINITION 17 energy consumption limits lifespan - more readily you consume energy, the shorter your lifespan will be because you are aging faster TERM 18
How do we measure energy consumption?
DEFINITION 18 metabolic rate (MR) - rate at which an organism consumers energy; basal metabolic rate - standardize based on mass (m/O2/hr)/g TERM 19
Rubner's 5 mammals
DEFINITION 19 found that when compared MR to LS, larger animals had a longer lifespan and a lower mass specific MR but looking at LEE changed that TERM 20
LEE
DEFINITION 20 lifetime energy expenditure- regardless of how long you live, consume the same amount of energy
Pearl's Predictions
(Rate of Living Theory)1. between species, organisms have the same lifetime energy expenditure 2. within a species, an inverse relationship between MR and LS TERM 22
Conclusions from the Rate of Living Theory
DEFINITION 22
- evidence for and against but mostly against b/c MR does affect aging but not always - can't be the ultimate theory TERM 23
Good of the Species Theory
DEFINITION 23 anything so ubiquitous has to be advantageous... individuals age to make room for younger individuals; age for the good of the group TERM 24
Weismann's Corollaries
DEFINITION 24
- a finite lifespan ensures better adaptation to the environment2. aging is necessary to eliminate the old, thereby providing the young, vigorous animals with resources TERM 25
Problems with Weismann's Corollaries
DEFINITION 25
- confuses death with aging; extrinsic mortality will still happen which leads to evolutionary change; just because you don't die, doesn't mean you don't reproduce 2. group selection - alleles can spread in a population because of the benefits they bestow on groups of individuals - is wrongnatural selection works on individuals not groups NS is a mechanisms by which evolution operates b/c only the best individuals survive and reproduce
Non-adaptive Evolutionary Theory
- aging is not adaptive and natural selection should oppose senescence... TERM 32
Evolutionary Lessons learned from Life Tables
DEFINITION 32
- older individuals don't contribute much to the population2. early, deleterious mutations should be selected against 3. late deleterious mutations are not selected against * the force of natural selection weakens with age TERM 33
Genetic Mechanisms of The Evolutionary
Theory
DEFINITION 33
- Mutation Accumulation 2. Antagonistic Pleiotropy 3. Disposable Soma * these mechanisms are not mutually exclusive TERM 34
Mutation Accumulation
DEFINITION 34 (Evolutionary Theory of Aging) declining force of natural selection with age makes it difficult to remove deleterious mutations late in life; the passive genomic build-up of alleles with deleterious effects expressed only late in lifeselection shadow: at some point can't really do anything about mutations late in life b/c already reproduced TERM 35
Antagonistic Pleiotropy
DEFINITION 35 (Evolutionary Theory of Aging)active selection favoring alleles with beneficial early life effects but harmful effects later in lifeex) testosterone: opposes immune function and can lead to cancer (costs later in life) but is what allows to reproduce
Disposable Soma
organisms must balance the demands of maintaining their body or reproducing aka tradeoffs between reproduction and maintenance TERM 37
Predictions of Evolutionary Theory of Aging
DEFINITION 37
- organisms that lack a clear distinction between germline and soma should not age (binary fission)2. altering the rate of decline of natural selection should alter the aging rate - reducing the environmentally induced death rate; making late-life reproduction a greater component of fitness TERM 38
Grandmother Hypothesis
DEFINITION 38 answers why there is post-reproductive lifespan - having children is costly but your grandmother shares 25% of your genes so wants to see the success of offspring and their offspring TERM 39
Why should longevity evolve?
DEFINITION 39
- environmentally selected: sparse or unpredictable environments, reproduction limited to certain times - socially selected: diet and intelligence, interdependent social groups, development time; brain size and social groups reduce the chance of extrinsic mortality TERM 40
What are the requirements for Survival and
their mechanisms?
DEFINITION 40
- decrease blood loss: vasoconstriction to non-essential organs 2. provide NRG for muscle activity and keep brain functioning: increased HR to inc BP leads to inc O2 and glucose delivery 3. provide NRG (access stores): inc breakdown of glycogen to glucose4. reallocate NRG from non-essential systems: dec reproduction, growth, immune function 5. state of mind: decrease pain (stimulate opioid receptors
Anatomy of a glucocorticoid stress response
baselineelevated Cort recovery - line can be lower for chronic stress TERM 47
Chronic Stress and Effects
DEFINITION 47
- repeated or prolonged exposures to acute stress 1. chronically high CORT levels: CORT levels reach greater amts and recovery takes longer and est of a new baseline can occur 2. down-regulate other systems: immune, growth, reproduction; can cause delayed maturity and amenorrhea (in gymnasts) *extremely stressful situations can cause psychosocial short stature that can be reversed when removed form the situation TERM 48
Glucocorticoid Cascade Hypothesis
DEFINITION 48
- hypothalamus receptors destroyed and negative feedback inhibited so CORT stays around longer; more CORT leads to greater degradation old vs young elderly will have higher peak levels during a response and a slower recovery time with a higher baseline TERM 49
Stress and Cellular Aging
DEFINITION 49 accelerated telomere shortening stressed individuals had a higher percentage of total damage to DNA telomere length has an inverse relationship with stress TERM 50
Why does prenatal stress occur?
DEFINITION 50 HPA axis set up during development and stressed out mother effects the set-up of this axismaternal CORT is crossing the placenta and affecting the axis
What does prenatal stress result in?
people that were prenatally stressed tend to have over-reactive stress responses --certain amount of CORT to shut-off higher base because mother's CORT and end up with more receptors so it takes more to shut off --causes lower birth weight, reduced growth rate, males feminized and females masculinized, impaired immune function impaired --higher baseline cortisol, impaired ability to shut down stress response TERM 52
Neonatal handling
DEFINITION 52 prenatal stress results reversed and almost lowered because handling resulted in increased parental care in mice --lower baseline CORT and more quickly shuts down stress responseneonates given attention tend to have hypoactive stress responses TERM 53
Hormesis
DEFINITION 53 stress isn't all bad, even some chronic stress can be ok beneficial effect resulting from the response of an organism to a low intensity stressor exercise can be a stressor (depends on regime) CR and LS = hormesis, low levels of stress can upregulate defense mechanisms, but there may be tradeoffs in other systems such as growth and reproduction TERM 54
Vitamins
DEFINITION 54 organic compound necessary for health but don't provide energy water soluble: C, B (plasma)fat soluble: A,D,E, K (cellular membrane) TERM 55
Vitamin C &
Megadose
DEFINITION 55 10 mg/day will prevent scurvy and 60mg/day is the recommended doesMegadose of Vitamin C: - H2O soluble so no problem with accumulation- but interferes with a number of common medical tests such as glucose and alters other nutrient absorption- vitamin C to oxalic acid to kidney stones* can act as a pro-oxidant by donating e- (works as AOx by reducing molecules or donating e-) to iron which becomes a free radical
Lifespan vs Healthspan
lifespan: the max number of years a species/pop attainshealthspan: the number of disease free years - exercise might not have the greatest impact on lifespan but can significantly increase healthspan TERM 62
How do you measure fitness level?
DEFINITION 62 vital capacity: max volume of air expired after a maximal inspiration
