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Flashcards in Ageing heart and lungs Deck (24)
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1

Describe what happens to veins as they age

  • Veins dilate and stretch with reduced elasticity 
  • Intima and muscle walls thicken
  • Does not have very much affect on function

2

 What 3 things occur to cause thickening of the arterial wall?

  • Increased collagen
  • Reduced elastin
  • Calcification 

3

With ageing, there is increased arterial wall stiffness and reduced compliance. Large arteries also can become elongated and tortuous. What does this in turn lead to?

Increased systolic blood pressure 

4

Describe what happens to the arteries in terms of nitric oxide levels

  • Reduced nitric oxide production by endothelial cells
  • Bioavailability of nitric oxide reduces w/ ageing
  • Nitric oxide lowers risk of atheroma formation (?)
  • Vasoconstriction is promoted

5

What happens to the cardiac myocytes (heart muscle)?

  • Ventricular cardiac myocytes hypertrophy in response to increased afterload
  • Enlargement of cardiac myocytes due to addition of sarcomeres
  • Apoptosis + necrosis of myocytes also occurs
  • Problems with oxygenating these cells as they are thicker

6

What happens to ventricular filling with age?

  • Left ventricular filling during early stage of diastole slows w/ age
  • Adequate filling occurs in late stage of diastole by the left atria contracting
  • Enlargement + hypertrophy of left atrium occurs 

7

What happens to the heart rate with age?

  • Intrinsic heart rate reduces by 5-6 beats/min per decade
  • Max heart rate achieved reduces with age
  • Variability of heart rate reduces  

8

What happens to the cardiac output with age?

Reduced cardiac output reserve, due to:

  • Reduced cardiac contractility
  • Reduced blood volume in left ventricle
  • Reduced maximum heart rate

During stress, cardiac output cannot increase

9

What changes occur within the conducting system of the heart?

  • Reduced # of pacemaker cells at SAN
  • Fibrous, fat + amyloid infiltration of conducting system
  • Slower propagation of electrical impulses due to hypertrophy
  • Atrioventricular node less affected

10

What are the 3 outcomes of the ageing conduction system?

  • Premature atrial beats
  • Ventricular ectopics (premature/irregular beat)
  • Higher risk of clinically significant arrhythmias

11

What happens to the heart valves during ageing?

  • Thicken and stiffen
  • Calcification
  • Scarring
  • Murmurs due to thickened valves

12

What are the overall impacts of an ageing CVS?

  • Increased systolic blood pressure
  • Reduced heart rate (esp max HR)
  • Reduced cardiac output reserve
  • Increased risk of arrhythmias
  • Increased risk of heart murmurs 

13

What happens to the alveoli with age?

  • Reduced elastic tissue in alveoli ducts -> thinner
  • Reduced SA for gas exchange
  • Decreased elastic recoil -> small airways collapse

14

Why is gas exchanged reduce in an older person?

  • They are perfusing parts of the lung that aren't getting properly ventilated so there is an increased ventilation-perfusion mismatch
  • -> increased alveolar-arterial gradient
  • Oxygenation not as efficient
  • Reduced gas exchange 

15

How does carbon dioxide excretion change with age?

It doesn't - stays the same

16

How does chemoreceptor function alter with age?

  • Impaired chemoreceptor function
  • Reduced ventilatory response to reduced PaO2 or increased PaCO2 

17

Why is there increased chest wall stiffness with age?

  • Degenerative changes in intercostal, intervertebral + costovertebral joints
  • Kyphoscoliosis
  • Weaker respiratory muscles
  • Increased work of breathing during stress

18

What changes occur in the respiratory muscles?

  • Weaker
  • Diaphragm flattens + becomes less effective
  • Intercostal muscles weaken
  • Abdominal muscles play greater role

19

What happens to pulmonary function, in terms of the following:

  • Forced vital capacity
  • FEV1
  • Total lung capacity
  • Residual volume
  • LFTs

  • Forced vital capacity decreases
  • FEV1 decreases
  • Total lung capacity remainds the same
  • Residual volume increases
  • Ability to perform lung function tests properly decreases w/ age

20

Why do elderly people have a less effective cough?

  • Reduced muscle strength
  • Less sensitive cough reflex

21

Why is mucociliary clearance less effective?

  • Reduced number of cilia
  • Slower + less effective
  • Take longer to recover after insult

22

How does surfactant composition change with age?

Increased proinflammatory proteins

23

What are the overall impacts of an ageing respiratory system?

  • Reduced gas exchange
  • Reduced ventilatory response to reduce PaO2 or increased PaCO2
  • Inceeased chest wall stiffness
  • Reduced microbial defence mechanisms

24

If there are all these problems with ageing lungs then how do 100 year olds run marathons?

  • Ageing of the lung leads to mild functional deterioration
  • It does not lead to symptoms without respiratory disease
  • In those w/ resp disease, symptoms will progressively worsen w age even if disease remains stable
  • When under stress (infection), earlier decompensation may occur