The physiology of ageing Flashcards Preview

Week 139 - Influenza > The physiology of ageing > Flashcards

Flashcards in The physiology of ageing Deck (22):
1

What are the effects of ageing?

Increased reliance of homeostatic reserves

Variable reduction in most organ function

Loss of functional reserve

Reduction in repair mechanisms

Increased prevalence of systemic disease

2

What are the theories of ageing?

Error theory

Free radical theory

Immune theory

Programmed theory of ageing – changes in cell replication

Neuroendrocrine theory

3

How is the cardiovascular system affected with age?

Artery stiffening -> Increased systolic arterial pressure

4

What are the consequences of increased systolic arterial pressure?

Increased systemic vascular resistance -> increased cardiac afterload -> increase left atrial size -> delayed relaxation and diastolic dysfunction (drdd) [drdd -> myocyte hypertrophy -> prolonged contraction -> drdd]

Systolic hypertension -> LVH

Changes result in decreased stroke volume
Attenuated increase in cardiac output during exercise
Reduced atrial pacemaker cells

5

How is the nervous system affected with age?

30% brain mass loss by age 80
Reduced production of neurotransmitters
Loss of motor, sensory and autonomic fibres
Slowing of conduction velocities/signal transduction rates
Reduced innervation in some myocytes
Increased sympathetic tone
Loss of vascular baroreceptor sensitivity

6

How is the cochlea affected with age?

Loss of hair cells
Loss of ganglion cells
Reduced fibres in cochlea nerve

=> presbyacusis = high frequency sounds

7

How are the eyes affected with age?

Astigmatism = flatter cornea
Lens and iris harden
Reduced ciliary muscle response -> impaired near vision
Vitreous humour floaters
Skin and muscle changes (enopthlamos, ptosis)
Small pupil
Sluggish light response

8

How is the renal system affected with age?

Reduction in cortical mass
Tubular atrophy and fibrosis
Reduced GFR (Sclerosis+loss of glomerular, lobulation reduction)
Increased basement membrane permeability
Decreased renal blood flow

Increased susceptibility to acute kidney injury
Reduced creatinine clearance
Effect on drug metabolism

9

How is the bladder affected with age?

Increased incidence of trabeculation and pseudodiverticula
Urethral epithelium becomes stratified squamous
Submucosa vascularisation is altered
Bladder capacity declines
Increased risk of UTI

Prostate enlargement (in some men)

10

How is the respiratory system affected with age?

Reduction in glandular epithelial cells, mucosa, and infection protection
Less elasticity of bony thorax
Muscle weakening and reduced mass
Reduced surface area of alveolar gas exchange
Reduced CNS responsiveness
Ventillation-perfusion mismatch and reduced arterial oxygen tension

11

How is the mouth affected with age?

Reduced saliva production
Impaired muscles of mastication
Tooth loss
Decrease in taste buds and therefore sensation
Decline in sense of smell
Tongue enlargement
Atrophic changes in jaw

All cause reduced food intake, impaired mastication

12

How is the upper GI tract affected with age?

Pharyngeal muscle weakness and abnormal relaxation of cricopharyngeal muscle

Reduced oesophageal peristalsis

Impaired relaxation of lower oesophageal sphincter

Desynchronisation causes impaired swallow safety

Increased incidence of achlorhydria with age caused by chronic atrophic gastritis

Malabsorption

13

How is the small bowel affected with age?

Shortening and broadening of villi

Impaired absorption/decreased efficiency in absorption

Reduced lipase production from pancreas

14

How is the large bowel affected with age?

Atrophy of mucosa and muscle layer
Cell infiltration of lamina propria and mucosa
Hypertrophy of lamina muscularis mucosa
Increase in connective tissue
Impaired motility with increased transit time with tendency for constipation

15

How is your immune system affected with age?

Impaired macrophage function
Slowing and reduction in complement pathway
Reduced B and T cell function
Cytokine dysfunction
Reduced production of TNFα/IL-1/NO
Increased autoimmune response

16

How is the skin affected with age?

Cosmetic factors
Impaired barrier function
Reduced epidermal cell turnover, keratinocytes and fibroblasts
Reduced vascular network
Reduced Vitamin D Synthesis

17

How is haematology affected with age?

Impaired reticulocytosis
Lymphopaenia
Poor quality response to stress events

18

How is the endocrine system affected with age?

Many changes in hormone concentration
Impaired glucose tolerance
Sexual dysfunction
Reduced testosterone in older men causes sarcopaenia
Increased serum ADH

19

How is your MSK system affected with age?

30% decline in muscle mass between 30-80 yo
Change in joint collagen fibre structure causes loss of elasticity
Bone loss (thinning of trabeculae and enlarged cancellous spaces) due to increased osteoclastic activity
Degenerative joint disease

20

How is thermoregulation affected with age?

Impaired temperature perception

Impaired body temperature maintenance

Impaired sweating/shivering/cutaneous/vasoconstriction/ hepatic thermogenesis

Increased susceptibility to hypothermia and hyperthermia and its effects

21

How is your psychology affected with age?

Slowing of response to stimuli

Slowing of central processing information

Difficulties in developing concepts

Poor abstract thinking/better at concrete tasks

More rigid/less flexible response to stressors

Curtail activities

Increased reflectiveness

22

How is your memory affected with age?

Require more time and effort to encode

Worsening of recall memory