Final answer:
The narrowing of the lower airways during expiration seen in conditions like asthma and pulmonary fibrosis significantly impacts breathing and gas exchange due to changes in lung compliance and resistance.
Step-by-step explanation:
Narrowing of the Airways During Expiration
The narrowing of the lower airways during expiration is a significant health concern that is commonly observed in conditions like asthma and restrictive lung diseases such as pulmonary fibrosis. During an asthma attack, the bronchioles become inflamed and constricted, leading to muscle contractions that narrow the airways, coupled with an overproduction of mucus. In restrictive diseases like pulmonary fibrosis, the lung tissue displays decreased compliance due to stiffening or fibrosis, resulting in a collapsed airway upon exhalation which traps air in the lungs.
These conditions alter both breathing and gas exchange by affecting the compliance and resistance of the lung tissue. These changes can lead to a V/Q mismatch and contribute to the difficulty in breathing. Gas exchange is further compromised in these diseases, leading to decreased oxygen delivery to the body's tissues. The treatment for these conditions involves medications, breathing therapies, and avoiding known triggers that can exacerbate symptoms.