Ageing Flashcards

1
Q

What are the 4 key words associated with ageing?

A

Normal
Universal
Inevitable
Irreversible

(Disease is the opposite of these)

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2
Q

What are the four ageing theories?

A
  1. Evolutionary
  2. Cellular
  3. Molecular
  4. System
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3
Q

What is the evolutionary theory of ageing?

A

Cells of the body are not designed to live forever and are DISPOSABLE. As long as DNA in germ cells is intact and as passed on.

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4
Q

What affect do antioxidants have on free radicals?

A

They can “mop them up” (get rid of them)

Antioxidants are in things such as fruit and veg.

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5
Q

What are free radicles?

A

“highly reactive molecules which cause damage to cellular components”

Arise during metabolism and can cause damage due to factors such as pollution, cigarette smoke and radiation.
They damage DNA, lipids proteins and mitochondria and accumulates with time.

Free radicals decrease an organisms ability to maintain steady state (homeostasis)

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6
Q

What is the cellular theory of ageing?

A

Ageing is associated with mitochondrial dysfunction. It leads to reduced ATP production and generation reactive oxygen species.

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7
Q

Oxidative stress and disease

A

An imbalance between production of radical oxidative stress and antioxidant results in oxidative stress. It causes intracellular damage and physiological decline. E.g. Cataracts, stroke, high BP, cancer, wrinkles.

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8
Q

What are telomeres?

A

They are a programmed part of the ageing process.
The body’s oxygen free radicals can modulate the reduction of telomeres.

When a cell stops replicating it enters a period of decline called CELL SENESCENE - this is the cellular equivalent to ageing (telomeres length reduces)

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9
Q

Homeostatic reserve mechanism

A

Ageing is a progressive physiological process that is characterised by degeneration of organs and systems and tissues with consequent loss of functional reserve in these systems.
Termed “homeostenosis” - It leads to increased vulnerability to disease that is seen with ageing.

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10
Q

What is homeostenosis?

A

A decreased ability to maintain homeostasis (balance) under stress. It is the impaired ability to compensate to physiologic challenges - things that used to be normal are no longer normal.

Damage that may be withstood in a younger person pushes the elderly beyond their functional capacity causing decompensation, disease or death.

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11
Q

What affect does a reduced functional reserve have on the respiratory system?

A
  1. Decreased blood flow to pulmonary circulation leads to decrease of diffusion in lungs
  2. Degeneration and reduced strength leads to an increase in righty of chest wall (less easy to expand rib cage)
  3. Muscle atrophy of pharynx and larynx which affects the cough reflex
  4. Decreased pulmonary elasticity = alteration in alveolar shape = ⬇️ SA for gas exchange
  5. Shorter/shallower breaths taken with decreased maximum breathing capacity
  6. Airway resistance is increased making it harder to draw air in to the lung and less ventilation at the lung base
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12
Q

How does changes in the respiratory system affect an older person who has developed a chest infection?

A

Narrowed airway due to inflammation and mucus production will further decrease air reaching lungs

Increase work of breathing will take more energy and could lead to breathlessness

Further decrease in gas exchange and decrease in O2 levels in blood (hypoxia)

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13
Q

Affects of ageing on nervous system…

A

Gradual loss of neurons and some supporting neuroglial cells (brain mass ⬇️ 10% between 20-90 yrs)

Loss of neurons in cerebral cortex = decrease in executive function (can take longer to understand instructions and remember info)

Loss of neurones in hippocampus = memory loss and decrease in acquisition skills

Cerebral flow decreases by around 20%

Spinal cord changes - sight, taste and smell loss

Reduced neurotransmitter production

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14
Q

How are synaptic connections maintained even with the loss of neurons?

A

Lengthening axons and sprouting dendrites allow synaptic connections to be maintained between neurones

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15
Q

What are the main issues that come with ageing?

A

Less able to recover from illness

Issues with maintenance of homeostasis

Functional capacity is decreased (esp when stressed)

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16
Q

What is an age related change in the lungs?

A

Weakening of the respiratory muscles

17
Q

How do telomeres affect ageing?

A

They have a protective agent against ageing and as they shorten to a critical length the protective effect is lost.
The length of a telomere determines the cells age and how many more times it will replicate.

18
Q

What is the molecular theory?

A

the insulin pathway can influence longevity and human ageing.

Calorie restriction has shown to prevent ageing as it leads to lower insulin levels, lower triglyceride levels and less free-radical damage.

Insulin regulation and oxygen radicals and important in ageing.

19
Q

What is the system theory of ageing?

A

The progressive decrease in physiological capacity and reduced ability to respond to env stressed leads to increased susceptibility and vulnerability to disease. Mortality due to these causes increased with age.