Problem
Scenario I
Jos has been diagnosed with emphysema (an obstructive disease of the airways). Jos finds it relatively easy to breathe in, but when breathing out his airways close and it is difficult to forcefully exhale the air in his lungs. In addition, emphysema leads to the destruction of alveoli walls therefore leading to larger but few air sacs (alveoli).
Task
Answer the following questions regarding how emphysema affect the normal function of Jos's respiratory system?
i. Explain what lung volumes and/or capacities may be affected by Jos's obstructive respiratory condition.
ii. Explain how gas exchange in the alveoli is affected and why.
iii. Using the bicarbonate buffer system equation (CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-), explain what would happen with his blood carbon dioxide levels and blood pH in obstructive respiratory conditions.
Scenario II
Abby has previously been diagnosed with chronic bronchitis - a long-term inflammatory disease of the airways that results in thick viscous mucous obstructing multiple airways. Abby's recent visit to the hospital diagnosed her with right-side heart failure (an inability for the right-side of the heart to work as an efficient pump) due to her unmanaged pulmonary hypertension. A consequence of this is peripheral oedema (fluid shifting from the intravascular space to the interstitium).
Task
Answer the following questions regarding how chronic bronchitis and right-side heart failure affect the normal function of the respiratory and cardiovascular systems.
i. Describe two protective mechanisms present in the respiratory tract to help prevent the passage of bacteria deep into the lungs.
ii. Using your understanding of ventilation-perfusion coupling (V/Q), explain how the respiratory (ventilation) and cardiovascular (perfusion) systems would respond to the airway obstructions and how this may result in pulmonary hypertension.
iii. Using your understanding of capillary exchange, explain how right-side heart failure can alter capillary exchange dynamics and cause peripheral oedema.