Pathophysiology of resp disease p2

Question 1

What is COPD

Answer 1

Chronic obstructive pulmonary disease -> Varying resp diseases involving both chronic bronchitis and emphysema. Long term decline in respiratory function

Question 2

Describe the inflammatory response due to tobacco smoke

Answer 2

Immune cells are attracted to damage tissues caused by chemicals. The immune cells release proteolytic enzymes, breaking down dead cells and killing invading organisms. This is dangerous with chronic exposure.

Question 3

Why is tobacco smoke dangerous with more chronic exposure

Answer 3

Constant cycles of damage and incomplete tissue repair, and because the balance between proteases and anti-proteases is disrupted

Mucociliary clearance is impaired due to increased mucus secretion and damage to cilia. This further exacerbates level of inflammation and long term damage to airway + lungs

Question 4

What is chronic bronchitis

Answer 4

Long-term inflammation of the bronchi/airways characterised by chronic sputum production, coughing and airway obstruction. Constant inflammation activates sensory neurons and mucus glands, causing coughing and more mucus

Question 5

What is the primary cause of airway dysfunction in chronic bronchitis

Answer 5

Lumen size reduced by excessive mucus secretion, tissue swelling and degradation of airway structure.

Question 6

What is emphysema

Answer 6

Pathological enlargement of alveolar airspaces due to destruction and degradation of lung tissue. Results in loss of structural fibres such as elastin (increasing compliance) as well as reduced SA and damage to pulmonary vasculature.

Question 7

What is the net effect of chronic bronchitis and emphysema

Answer 7

Ventilation and gas exchange reduced -> Respiratory failure, knock-on effecrt

Question 8

How does respiratory failure place burden on the CVS

Answer 8

Chronic hypoventilation of alveoli results in prolonged hypoxic vasoconstriction. More force required to pump blood through system, due to increased resistance. Right heart hypertrophy.

Eventually leads to heart failure, increased venous pressure and right ventricular afterload.

Question 8

How does respiratory failure place burden on the CVS

Answer 8

Chronic hypoventilation of alveoli results in prolonged hypoxic vasoconstriction. More force required to pump blood through system, due to increased resistance. Right heart hypertrophy.

Eventually leads to heart failure, increased venous pressure and right ventricular afterload.

Question 9

What is pneumonia

Answer 9

Infection of the lung parenchyma (alveoli and surrounding tissue)

Question 10

Describe the infection of pneumonia

Answer 10

Pathogens colonise alveoli, activating macrophages and release of cytokines. Recruits neutrophils to the lungs, releasing more cytokines, reactive oxygen species and proteases. This fights the infection and injures surrounding tissues, negatively impacting alveoli.

Question 11

Acute lung injury can lead to

Answer 11

Acute respiratory distress syndrome and death due to acute respiratory failure

Question 12

Alveoli injury causes

Answer 12

Excessive fluid drawn into alveoli and surrounding interstitial tissue. Oedema occurs, reduces gas exchange due to increased diffusion distance.

Question 13

Damage to the alveolar wall and accumulation of dead cells and waste causes

Answer 13

Hyaline membrane formation (where membranes that are normally thin and selectively permeable become thick and relatively impermeable) limiting gas exchange

Question 14

Impaired gas exchange causes

Answer 14

Hypoxaemia