The Distribution of Air Depends on the Local Mechanical Properties of the Lung
Optimal gas exchange requires bringing together air and blood at the alveolus, that is, the matching of ventilation and blood flow. Obviously, gas exchange cannot occur if an alveolus receives blood but no ventilation, or vice versa.
Ideally, each region of lung should receive approximately equal amounts of ventilation, but this never occurs in either animals or people. Distribution of ventilation is always uneven to some degree and becomes more so in disease. Uneven distribution of ventilation can be caused by local decreases in lung compliance (e.g., in pneumonia) or local airway obstructions (e.g., by mucus or bronchospasm) (Figure 45-11).The distribution of ventilation is very uneven in recumbent large animals, especially in the supine and laterally recumbent positions. This is because the lowermost regions of the lung are compressed to such an extent that they receive little or no ventilation. This can cause severe derangements of gas exchange in anesthetized horses.
More on the topic The Distribution of Air Depends on the Local Mechanical Properties of the Lung:
-
Veterinarian -