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Flashcards in The pathology of ageing Deck (22)
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1
Q

How does a cell’s division capability change over time

A

Progressively undergoes fewer divisions

2
Q

What is a hay flick limit

A

This is the maximum number of cell divisions in a species

3
Q

What type of mammals tend to have high hay flick limits

A

Those with a larger lifespan

4
Q

What metric does the hay flick limit define

A

The shortening of the telomeres with each successive division

5
Q

Why are short-lived cells less effected by debris than longer-lived cells

A

They divide cytoplasmic debris with each of their daughter cells. This does not happen with long-lived cells

6
Q

Where does accumulated cytoplasmic debris originate from

A
  1. Peroxidation of lipids forms indigestible lipofuscin
  2. Intracellular aggregates of defective proteins
  3. Defective mitochondria
7
Q

What is the inbuilt genetic mechanism of aging theory (clonal senescence)

A
  1. Genetically we have an allowed lifespan that is finite
8
Q

Why do no wild animals live to the allowed lifespan of the genetic raging theory

A

Due to predation, infections and accidents

9
Q

Describe the replication senescence

A
  1. Some cells stay with us from birth to death and we lose these cells during our daily life
  2. Accumulation of lethal damage causes whole organism to succumb (e.g. CNS and cardiac)
10
Q

What is an accumulation of ‘lethal damage’

A

Cross-linking between proteins and DNA

Damage to mitochondria

11
Q

Where do free radicals form

A
  1. Macrophages

2. Neutrophils

12
Q

How does defective repair result in raging

A
  1. Hayflick phenomenon states cells can only divide a limited number of times under genetic control
  2. If i damage the gastric mucosa, there may come a time where the cells can no longer replicate to heal the ulceration
13
Q

How does telomeric shortening cause ageing

A
  1. Become too short that DNA polymerase in unable to find the start position for transcription
  2. Associated with hay flick limit of cells
14
Q

What is sarcopenia

A

Part of the frailty syndrome

  1. Reduced metabolic rate
  2. Chronic poor nutrition
  3. loss of muscle
15
Q

How does skin age

A
  1. Loss of elastic recoil due to less collagen and elastin
16
Q

How does ageing effect bone

A

Loss of bone mass - osteoporosis as trabecular are thinned

17
Q

Why does osteoporosis occur

A

Accumulation of of minor traumas over time

18
Q

Why does immunity slow down with age?

A
  1. Thymus is source of T cells and undergoes atrophy
  2. Most of the thymus is replaced by adipose tissue
  3. decreased output of native t cells
19
Q

What are cardiovascular changes that come with ageing

A
  1. Distensability of arteries reduces with age + raised systolic blood pressure and PP
  2. Ratio or collagen to elastin decreases in arteries as collagen levels increase
  3. Calcification causes atheroma
20
Q

What happens to permanent cells during ageing

A
  1. Decreased neurological function

2. Necrosis of tissues in the CNS

21
Q

Why are permanent cells in the heart and CNS a good thing

A

Very little chances of a tumour forming

22
Q

What are the clinical features of death

A
  1. Pupils fixed in diameter
  2. No corneal reflex
  3. Vestibule-ocular reflexes are absent (no response to putting ice water in external ear canal)
  4. No gag reflex
  5. No respiratory movement
  6. No motor response

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