Physiology of Ageing Flashcards

1
Q

What are the two broad groups of Ageing theories?

A

Programmed Theories and

Error Theory

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2
Q

What Programmed Theories are there?

A

Programmed Senescence Theory - Telemeres

Endocrine Theory

Immunology Theory

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3
Q

What Error theories are there?

A

Wear and Tear Theory

Rate-of-Living Theory

Cross-linking Theory

Free Radical Theory

Error Catastrophe Theory

Somatic Mutation Theory

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4
Q

What happens to the liver in ageing?

A

Liver size decreases by 45% with reduction in blood flow too (enzyme activity not affected).

Reduced production of albumin, clotting factors etc and

Impaired glucose metabolism.

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5
Q

What happens to the kidney in ageing?

A

Reduction in renal mass

Decreased cortical thickness

Diminished glomeruli and glomerular lobulation

Glomerular and vascular sclerosis

Tubular atrophy and fibrosis

Greater GBM permeability

ADH resistance

Impaired RA vasodilation ability

Creatinine levels are lower (lower muscle mass) therefore lower rises in creatinine are more significant (look at trends)

More likely to have urinary system problem

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6
Q

CVS changes in ageing?

A

Increase smooth muscle tone

Increase systolic vascular resistance / after load (isolated systolic hypertension)

Myocyte hypertrophy, lengthen contraction time

Increase left atrial size with age (AF)

Decrease in atrial pacemaker cells - conduction and rhythm disturbance

Venous stiffening

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7
Q

CNS changes in ageing?

A

30% reduction in brain mass by 80

Reduced production of catecholamine / serotonin / acetylcholine

Deplation of DA upatake site and depletion of cortical serotenergic / GABAnergic binding sites

Cognitive decline

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8
Q

PNS changes in ageing?

A

Loss of motor, sensory and autonomic fibres

Reduction in afferent and efferent conduction velocities

Number of muscle cells innervated bu each axon falls leading to denervation and muscle atrophy

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9
Q

ANS changes in ageing?

A

Increased sympathetic tone and reduced parasympathetic tone.

Reduced beta-adrenergic response as well

This leads to up-regulation of catecholamines giving high circulating levels

Reduced ability for aortic arch and carotid baroreceptors to respond to changes in arterial pressure.

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10
Q

GI tract changes in ageing?

A

Changing to involuntary stages of swallowing

Decreased secretion HCL and associated small rise in gastric pH

Decline in absorption of substances that use active transport eg B12

Prolonged transit time can cause constipation.

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11
Q

Resp changes in ageing?

A

Decline in elastic support of airways causing increased collapse of alveoli and small airways (harder work of breathing too)

Normal arterial O2 may be lower

Loss of muscle mass and weakening of muscles of respiration

Decrease in central nervous system responsiveness eg to CO2 and O2

Increased partial obstruction on inspiration (snoring) and sleep apnoea (OSA.)

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12
Q

Immune changes in ageing?

A

Macrophage function impaired

B cell and T cell function affected

Complement pathway is affected

reduced capacity to generate important mediator including TNF alpha, IL1 and NO

Increased auti-immunity with increased frequency of auto-antibodies against organ-specific and non-organ specific antigens.

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13
Q

Skin changes in ageing?

A

Reduced epidermal cell turnover,

Reduced vascular network

Increased fibrosis and skin atrophy

Reduction in vit D synthesis

Increased susceptibility to skin injuries including pressure ulcers and skin tears

Increased vulnerability to infections and neoplasia die to impaired immunity

Impaired thermoregulation

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14
Q

MSK changes in ageing?

A

Sarcopenia - age related loss of muscle strength

Loss of type 2 fibres (like in thighs)

Reduced force of contraction

Change in structure of collagen fibres within joints contribute to loss of elasticity

Loss of bone mineral density causing ostooporisis and increased risk of fracture

Osteoarthtirits

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