Excellent quality summary notes for Chapter 03 of the Honours module in Psychology at Unisa (PYC4805). Perfect for assignments, multiple choice, essays and examinations. The notes were created using the book - Adult Development & Aging (2019), Cavanaugh & Blanchard-Fields (8th edition).
Test Bank For Adult Development and Aging 8th Edition by John C. Cavanaugh, Fredda Blanchard-Fields 9781337559089 Chapter 1-14 Complete Guide.
Test Bank For Adult Development and Aging 8th Edition by John C. Cavanaugh, Fredda Blanchard-Fields 9781337559089 Chapter 1-14 Complete Guide.
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PYC4805 - Developmental Psychology (PYC4805)
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PYC 4805:
Developmental
Psychology
Chapter 3
, 1. Why do We Age? Biological Theories of Aging
1.1. Metabolic Theories:
» One theory of aging that makes apparent common-sense postulates that organisms have only so much en
expend in a lifetime.
- Couch potatoes might like this theory and may use it as a reason why they are not physically active.
» The basic idea is that the rate of a creature's metabolism is related to how long it lives.
» Several changes in the way that hormones are produced and used in the human body have been associate
but none have provided a definitive explanation.
» Although some research indicates that significantly reducing the number of calories animals and people e
increase longevity, research focusing on nonhuman primates shows that longer lives do not always result f
restricting calories alone.
» Furthermore, the quality of life that would result for people on such a diet raises questions about how goo
calorie restriction is.
- That's because the calorie Chris tractions in this research tend to be extreme.
» Extrapolated to people, the restrictions could well cause a drop in humans’ ability to engage in the kinds o
would consider important for a high quality of life.
, 1.2. Cellular Theories:
» A second family of ideas points to causes of aging at the cellular level.
» One notion focuses on the number of times cells can divide, which presumably limits the lifespan of a com
Organism.
» Cells grown in laboratory culture dishes under girl only a fixed number of divisions before dying, with the n
possible divisions dropping depending on the age of the donor Organism ; This phenomenon is called the
after its discoverer, Leonard Hayflick.
- It turns out that the Hayflick limit sets an upper bound on the number of cell divisions possible even in th
other factors, such as telomere damage.
» What causes cells to limit their number of divisions?
- Evidence suggests that the tips of the chromosomes, called telomeres , play a major role in aging by adju
response to stress and growth stimulation based on cell divisions and DNA damage, and by typically short
each cell replication.
» An enzyme called telomerase is needed in DNA replication to fully reproduce the telomeres when cells div
- But telomerase Normally is not present in somatic cells, so with each replication the telomeres become s
- Eventually, the chromosomes become unstable and cannot replicate because the telomeres become too
» Chronic stress may accelerate the changes that occur in telomeres and thereby shorten one's life span.
- Research also shows that moderate levels of exercise may maintain telomere length or at least slow the r
telomeres shorten, which may help slow the aging process itself.
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