Airways

Question 1

Pathophysiology of asthma

Answer 1

• Always some element pf breathing obstruction
• Airflow is normally limited but reversible
• Airway hyper-responsive to stimuli
• Bronchospasm (smooth muscle contraction to narrow airways)
• The bronchi are always in a state of chronic inflammation

Question 2

pathophysiology of COPD

Answer 2

1. Elastic tissue loss -> Chronic obstruction and collapse of lung airways
2. This creates a constant increase/ retention of carbon dioxide in the blood – the carbon dioxide cannot be expelled
3. Normal physiology – Central chemoreceptors in medulla oblongata pick up high co2 level which provides breathing stimuli
4. As disease progresses central chemoreceptors become unresponsive to the constant co2 stimulus
5. Low o2 levels become stimulus for breathing
6. peripheral receptors situated in aortic arch and carotid bodies become essential for driving respiration (the hypoxic drive)
7. Administration oxygen levels that are higher than the COPD patient is used to may stop the stimulation to breathe/control of breathing
8. Carbon dioxide levels continue to rise when breathing becomes ineffective