Biological Aspects Of Ageing

Question 1

What is ageing?

Answer 1

Normal, inevitable process

Progressive physiological process characterised by degeneration of organ systems/tissues with consequent loss in functional reserve of these systems

Question 2

What is disease?

Answer 2

An abnormal, non inevitable process

Question 3

What are the correlations between disease and ageing?

Answer 3

As bodily systems age, increased susceptibility to disease

Life span appears to be limited by the ageing process rather than disease

Older people tend to be more vulnerable to disease

Question 4

What are the 4 main theories of ageing?

Answer 4

1) evolutionary
2) cellular
3) molecular
4) system

Question 5

What is the disposable soma theory?

Answer 5

Explains evolutionary significance of ageing

Distinction between somatic and reproductive tissue

Surrounds the idea that we conserve our bodies to reproduce and pass on our desirable genes/characteristics to our offspring (all energy and resources into passing on genes)

Organisms exposed to high risk invest little in maintenance and a lot in reproduction

Question 6

What is somatic tissue?

Answer 6

Parts of the body other than those involved in producing sperm/eggs

Question 7

What are free radicals/oxidants?

Answer 7

Free radical- an atom with an unpaired electron

Both highly reactive molecules- damage cellular components eg DNA in nucleus, structural proteins and enzymes

Causes molecules to become non-functional- may cause signs of ageing

Question 8

What does the free radical theory state?

Answer 8

Ageing results from damage generated by free radicals

Oxidative damage accumulates with age

Question 9

How are free radicals made?

Answer 9

Arise normally during metabolism from environmental factors

Question 10

What is oxidative stress?

Answer 10

When there is an imbalance between the production of free radicals and antioxidants- results in intracellular damage

Question 11

What are the role of antioxidants?

Answer 11

Mop up free radicals

Protect cell membranes from damage

Body can either make its own (endogenous-naturally occurring) or gained exogenously through foods etc like fruit/veg

Question 12

What are telomeres?

Answer 12

Protective structures at the ends of the chromosome, consisting of repeating units of DNA

Programmed part of ageing process

Question 13

How are telomeres associated with age?

Answer 13

Thought I have a protective effect against ageing

As they progressively shorten to critical length, protective effect is lost- leading to apoptotic cell death

Question 14

What does the length of the telomere show?

Answer 14

Cells ages and how many times it will replicate

Question 15

What is cell senescence?

Answer 15

The period of decline the cell enters when the cell has stopped replicating

Cellular equivalent of ageing

Question 16

What have animal models shown about lifespan?

Answer 16

Possible to cause a mutation in a gene involved in the insulin pathway- increases healthy lifespan

Question 17

What is the variant gene FOXO3a?

Answer 17

Involved in the insulin pathway

Question 18

What does a mutation in the FOXO3a imply?

Answer 18

Less risk of developing diabetes/cancers

Suggest role in the insulin pathway to influence longevity and human ageing

Important in future development of therapies to support human beings?

Question 19

What is the association between calorie restriction and ageing?

Answer 19

Delay/slow ageing in mammals

Lower insulin levels/triglyceride levels

Less free-radical damage

Enhances idea insulin regulation/oxygen radicals are important in ageing

Question 20

What does organ reserve mean?

Answer 20

Organs have a certain capacity to withstand perturbations and return to homeostasis

Question 21

What is Homeostenosis?

Answer 21

Reduced capacity/ability to respond to a changing environment

Increased venerability to disease seen with ageing

Normally physiologic reserves allow us to maintain homeostasis in the presence of environmental, emotional and physiological stress BUT with this, an insult that may have been withstood when younger pushes an elderly person beyond their functional capacity