13: Ventilation and Perfusion
- Page ID
- 34578
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- Derive the consequences of changing V/Q (from 0 to infinity) on alveolar and arterial gas tensions.
- Describe the consequences of regional variation in V/Q across the lung from apex to base on alveolar and arterial gas tensions.
- Describe the response of the pulmonary vasculature to changes regional of ventilation.
- 13.2: Distribution of V/Q
- As you should understand, ventilation increases down the lung so is greatest at the base, and perfusion follows the same pattern – all due to the effects of gravity. But the increase in ventilation down the lung structure is not equal to the increase in perfusion with perfusion higher than ventilation at the base, but falls off much more rapidly as the lung is ascended, so ends up being lower than ventilation at the apex.