Pathophysiology of COPD

Question 1

What is Chronic obstructive pulmonary disease(COPD)?

Answer 1

Is a mixture of chronic bronchitis and emphysema and encompasses a long term, progressive and accelerated decline in respiratory function

Question 2

Why does smoking harm the respiratory system?

Answer 2

-Contain many harmful constituents of tobacco smoke which cause acute damage to respiratory tissue, generating an inflammatory response

Question 3

What happens when there is repeated exposure to smoking?

Answer 3

With repeated exposure, the inflammation becomes pathological and generates chronic and irreversible dysfunction

Question 4

Inflammation observed within lungs of COPD patients

Answer 4

See flowchart and diagram

Question 5

What is imparied in COPD and due to what reason?

Answer 5

Mucocilary function is impaired due to damage to cilia and mucus hypertension

Question 6

Pathological features observed within airways of COPD patients

Answer 6

• Damage to cilia
• Mucus hypersecretion(Due to increase in goblet cells and mucus gland activation
• Inflamed, swollen airway
• Weakened airway structure(Loss of elastin)and loss of patency

Question 7

What does impaired mucociliary clearance result in and lead to?

Answer 7

• Results in an increased risk of infection

- Can lead to recurrent infection

Question 8

What leads to a cough?

Answer 8

Irritation of sensory neurones

Question 9

What does decreased luminal area increase?

Answer 9

Increased airway resistance and airway obstruction

Question 10

Pathological features observed within lungs of COPD patients

Answer 10

Emphysema(Airspace enlargement)

Question 11

What will emphysema do to surface area and perfusion and what will this ultimately result in?

Answer 11

• Decrease surface area and perfusion

- Leads to a decrease in gas exchange

Question 12

What happens to elastin fibres in emphysema and what does this result in?

Answer 12

• Loss of elastin fibres

- Leads to an increase in compliance and a decrease in recoil

Question 13

What do elastin in surrounding alveoli provide in healthy alveoli?

Answer 13

-Provide radial traction to splint against positive alveolar pressure

Question 14

what happens to bronchioles in COPD?

Answer 14

-No radial traction in COPD, therefore bronchioles collapse

Question 15

Overall effect of COPD on respiratory function

Answer 15

See flowchart

Question 16

What does COPD exacerbation’s reduce and contribute to?

Answer 16

• Reduce lung function drastically

- Plus contribute to decline

Question 17

What is one pathway that chronic alveolar hypoxia can lead to?

Answer 17

1) Hypoxic vasoconstriction=Increased pulmonary vascular resistance
2) Pulmonary hypertension
3) Increased right ventricular afterload leading to right ventricle hypertrophy
4) Results in right heart faliure

Question 18

What is the most effective way of slowing decline and preventing COPD?

Answer 18

-Smoking cessation however lung function doesn’t regenerate and decline continues but not as rapidly

Question 19

How could the pathophysiology of COPD be modelled in animals?

Answer 19

• Expose mice to tobacco smoke for a certain period of time
• Measure lung infection, airway resistance and compliance
• Cull animals and take bronchoalveolar and lung tissue samples
• Measure cytokine and leukocyte levels.Obseve histological changes in lung

Question 20

What else does chronic alveolar hypoxia lead to?

Answer 20

• Causes hypoxaeima, hypercapnia and acidemia

- Leads to decreased exercise tolerance and a decrease in quality of life