Immunology and Aging Quiz

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Questions and Answers

What is immunosenescence characterized by?

Decreased memory T-cells

Increased IL-7 production

Increased naive T-cells

Decreased naive T-cells (correct)

Which of the following factors is directly associated with the decreased number of naive T-cells?

Shrinking of the thymus (correct)

Increased IL-7 cells

Decreased apoptosis

Increased fat in the body (correct)

What change in the immune system is indicated by increased levels of IgA and IgB in the blood?

Autoimmune disorders (correct)

Improved immune response

Enhanced vaccine efficacy

Normal aging process

What role does apoptosis play in the immune system?

Controls immune responses and deletes immune cells Signup and view all the answers

Which theory of aging suggests that wear and tear leads to older cells losing functionality?

Wear and Tear Theory Signup and view all the answers

What does the Rate of Living Theory imply about metabolism and aging?

Higher basal metabolism results in faster aging Signup and view all the answers

What is the Free Radicals Theory primarily concerned with?

Damage caused by superoxide and free radicals Signup and view all the answers

Who devised the Wear and Tear Theory?

August Weismann Signup and view all the answers

What does the programmed longevity theory suggest about genes?

They are pre-programmed to change over time. Signup and view all the answers

According to twin studies, what percentage of age at death is attributed to hereditary factors?

25% Signup and view all the answers

What role does the hypothalamus play in the endocrine theory of aging?

It triggers the release of hormones that control aging. Signup and view all the answers

What was discovered about lifespan in mice after the removal of the pituitary gland?

Lifespan increased by 15% and 21% depending on age at removal. Signup and view all the answers

What does the immune theory of aging propose?

Immune dysfunction may contribute to the aging process. Signup and view all the answers

Which of the following is cited as evidence for the endocrine theory of aging?

Increased growth hormone and insulin-like growth factor in engineered mice. Signup and view all the answers

What percentage of centenarians' male children are more likely to live to be 100?

0.1% Signup and view all the answers

Who developed the endocrine theory of aging?

Vladimir Dilman Signup and view all the answers

What does the cross-linking theory suggest about the effect of protein cell fusion?

It leads to structural changes and chemical releases that impair functionality. Signup and view all the answers

In the study by Bjorkstein and Tenhu, what was indicated by a low amount of non-freezing aggregates in older brains?

More cross-linkage in older brains. Signup and view all the answers

What is the primary characteristic of free radicals as described in the free radical theory?

They have unpaired electrons and can damage healthy cells. Signup and view all the answers

Which substances are mentioned as effective in neutralizing free radicals?

Anti-oxidants from food sources. Signup and view all the answers

What was the contribution of Bjorkstein & Tenhu in their 1990 study?

They provided evidence supporting the cross-linking theory of aging. Signup and view all the answers

According to the free radical theory, what is the relationship between oxidant production and longevity?

Lower oxidant production is associated with increased lifespan. Signup and view all the answers

What is one common source of free radicals mentioned in the content?

Unstable atoms in our tissues. Signup and view all the answers

Why is there an increased need for antioxidant consumption as we age?

The ability to remove oxidants from our systems declines. Signup and view all the answers

How does reduced cellular metabolism affect cells in the heart, brain, and muscle?

It impairs their ability to replace themselves effectively. Signup and view all the answers

What does the rate of living theory suggest about metabolic rates and aging?

Faster metabolic rates result in faster aging. Signup and view all the answers

What does the programmed theory of ageing suggest about cells?

Cells have a finite lifespan that follows a timeline. Signup and view all the answers

What is one of the main pieces of evidence supporting the rate of living theory?

Body mass dictates metabolic output in animals. Signup and view all the answers

What factor did the Jumpertz study identify as a risk for earlier mortality in Pima Indians?

Higher endogenous metabolic rate. Signup and view all the answers

Which line of evidence is associated with the idea that certain genes switch on and off over time?

Programmed longevity Signup and view all the answers

What role does the endocrine theory play in the programmed theory of ageing?

It indicates regular hormonal changes control the process of ageing. Signup and view all the answers

Which of the following statements reflects a misconception about cellular repair in aging?

Cellular repair capabilities are entirely lost with age. Signup and view all the answers

Which of the following does the immunological theory of aging emphasize as a challenge to healing?

Autoimmune inflammation. Signup and view all the answers

How does the immunological theory contribute to the understanding of biological ageing?

It indicates that the immune system's effectiveness is pre-programmed to decline. Signup and view all the answers

What does the concept of 'wear and tear' in aging suggest?

Aging is linked to accumulated damage. Signup and view all the answers

What is a potential pro of the programmed theory of biological ageing?

It provides a clear timeline for individual lifespan. Signup and view all the answers

What does evidence against the theory of wear and tear suggest about organisms?

They can improve their resilience as they age. Signup and view all the answers

What is considered a con of the programmed theory of ageing?

It fails to account for genetic variations among individuals. Signup and view all the answers

What overarching theme does the study of biological ageing address?

The biological processes that lead to ageing and related diseases. Signup and view all the answers

What is the significance of understanding the theories of biological ageing?

It plays a role in improving diagnosis and treatment of age-related conditions. Signup and view all the answers

What is the effect of physical activity on telomeres?

It lengthens telomeres. Signup and view all the answers

Which type of diet is associated with shorter telomeres?

High in omega-6 fatty acids. Signup and view all the answers

What ingredient in red wine is noted for activating longevity proteins?

Reservatrol. Signup and view all the answers

How is obesity linked to aging at a cellular level?

It is associated with increased shortening of telomeres. Signup and view all the answers

Which of the following factors can potentially affect biological aging?

Lifestyle factors including stress and diet. Signup and view all the answers

What role does caloric restriction have in relation to longevity?

It is associated with longevity benefits. Signup and view all the answers

Which habit is linked to shorter telomeres due to diet?

Increased intake of fizzy drinks. Signup and view all the answers

What is the relationship between telomerase activity and aging?

Greater telomerase activity is associated with less shortening of telomeres. Signup and view all the answers

Study Notes

Biological Theories of Ageing

Biological ageing is a complex process with multiple contributing theories.
There are two main categories of theories: Programmed and Error (or Damage).

Programmed Theories

Programmed longevity: This theory suggests that our genes are pre-programmed to change over time, leading to the physical and mental symptoms associated with ageing.
Evidence comes from lifespan studies in animals where genetics have prolonged lifespan.
Three specific examples are: programmed longevity (certain genes switch on & off), endocrine theory (hormones control aging), immunological theory (immune system gradually declines, increasing sickness susceptibility).
Challenges to this theory lie in twin studies that show only 25% of age at death is explained by heredity, and most evidence is from animal studies with limited translation to humans. However, research on centenarians (extreme old age) offers a different perspective.
Endocrine theory: This theory suggests that hormones and reactions regulated by the hypothalamus play a role in controlling how fast we age.
Vladimir Dilman (1954) developed the theory.
The hypothalamus controls reactions within the body to release hormones, which become less effective with age.
Evidence from studies (Powers, Harrisons & Flurkey, 2006) on mice who had their pituitary glands removed showed a 15% and 21% longer lifespan, and genetically modified mice showed an increase in growth hormone and potentially increased lifespan.
Immunological theory: This theory postulates that our immune responses weaken as we age, increasing susceptibility to illness and disease.
Devised by Roy Walford (1969)
The decrease in immunity can lead to various chronic diseases with inflammatory components (e.g., arthritis, cancer, and Alzheimer's).
The mechanism behind this is likely due to reduced naive T-cells and increased memory T-cells which may misidentify foreign agents (cells/viruses).
There is evidence of cells shrinking, reduced fat and increased memory cells in blood.

Damage (or Error) Theories

Wear and tear: Cells and organs deteriorate over time due to repeated use, like a machine.
Devised by August Weismann.
Mechanisms can decline with repeated use, but damage may also increase given stress and autoimmune inflammation.
Evidence for this theory includes common perceptions of aging. However, cells can sometimes repair or continue to divide.
Rate of living: This theory suggests that faster metabolisms lead to faster aging.
Developed by Max Rubner (1908).
Evidence from Kleiber's Law (1932) suggests that a larger body mass (and thus faster metabolism) does predict a faster aging process, although there is also evidence that other factors may play a role like differing health conditions. For example, giant tortoises live for 150 years despite their body size.
Cross-linking: This theory suggests that proteins form cross-links in our tissues as we age.
Johan Bjorksten (1942).
This causes structural change and chemical release leading to damage in functionality.
An example includes collagen cross-linking in the cornea and reduction in elastic properties for vision.
Studies support this theory in that older brains had less non-freezing water than younger brains (Bjorkstein & Tenhu, 1990) but the mechanism's complexity still requires further study.
Free radical theory: This theory suggests that unstable atoms attack cells and cause illness.
Devised by Deham Harman (1956).
Instability from the free radicals can cause damage and result in accumulated damage and reduced function over time.
Antioxidants can counteract these effects. Studies support the idea that mice with additional Arf/p53 genes exhibit 16% increased lifespan (likely due to free radical removal).

Summary of Theories

Overall, aging is likely a multi-factorial process that involves a combination of programmed and damage theories.
Genes can only account for a limited percentage of lifespan.
Other determinants of aging include aspects such as behavior, exposures, and luck.

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Description

Test your knowledge on immunosenescence and theories of aging with this quiz. Explore topics including T-cell dynamics, the role of apoptosis, and various aging theories. Challenge yourself on how these factors connect with the immune system and longevity.