When do you expect the greatest airflow into the alveolus?

Mid-inspiration

What is the expected alveolar pressure at the End of Inspiration?

Zero

Restrictive lung disease/fibrosis --> thickening & stiffening of the pulm: interstitium --> increased lung elastic recoil,

• -> airway widening due to increased outward pulling (radial traction) by the surrounding fibrotic tissue -->
• -> decreased airflow resistance --> supernormal expiratory flow rates (higher than normal when corrected for lung vol:)

Airway Resistance

Regional airway resistance within the first 10 generations of bronchi contributes to most of the total airway resistance of the lower respiratory tract. Resistance is maximal in the 2nd-to-5th-generation airways, including the segmental bronchi.

In contrast, airways <2mm in diameter (eg, bronchioles) contribute <20% of the total airway frictional resistance.

For patients with stiff lungs (increased elastic resistance), the work of breathing is minimized when the respiratory rate is high and the tidal volume is low. Therefore, rapid and shallow breaths are favored in diseases that increase elastic resistance (eg., pulmonary fibrosis, pulmonary edema, acute respiratory distress syndrome).

In contrast, in diseases that cause high airflow resistance (e.g„ asthma, COPD), patients breathe at a lower rate (slow, deep breaths) in order to minimize the work of breathing.