A Model for the Contribution of Lung Receptors to the Control of Breathing: Positive and Negative Feed-Backs
Experiments in dogs in which pulmonary and systemic circulations were controlled separately have shown that minute ventilation (̇VE) increased when the CO2 content of pulmonary arterial blood was increased, while systemic arterial PCO2 was kept constant. Similarly, ̇VE also increased when pulmonary blood flow was increased at constant PCO2. These responses were abolished after bilateral vagal transection10, 20. We present two positive feed-backs which may account for the increases in ̇VE observed in these experiments. Further, a negative feed-back is presented controlling the CO2 related off-switch of inspiration.
KeywordsPulmonary Blood Flow Inspiratory Activity Pulmonary Stretch Receptor Alveolar Carbon Dioxide Expiratory Activity
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