Question

Breathing is critical to our survival. Pulmonary ventilation is the physiologic process of air entering and exiting the lungs. Since air flows from a high to a low pressure, both inspiration and expiration depend upon pressure gradients.

The weight of the air surrounding us creates atmospheric pressure. Since atmospheric pressure remains constant at a given location, our ability to move air into the lungs depends upon intrapulmonary pressure being lower than atmospheric pressure. In contrast, air won’t move out of the lungs until the intrapulmonary pressure rises higher than the ambient atmospheric pressure.

Intrapulmonary pressure varies as a result of changes in thoracic volume. Decreases in thoracic volume cause increases in the intrapulmonary pressure. In contrast, increases in thoracic volume result in decreases in intrapulmonary pressure. These thoracic volume changes depend upon the actions of respiratory muscles such as the diaphragm and external intercostals.

If intrapulmonary pressure was 760 mm Hg, what would you expect the intrapleural pressure to be? 764 mmHg or 756 mmHg

Answer 1

Intrapleural pressure is typically lower than intrapulmonary pressure to facilitate normal breathing. Therefore, if intrapulmonary pressure is 760 mm Hg, the expected intrapleural pressure would be 756 mm Hg.

Step-by-step explanation:

Pulmonary ventilation is primarily driven by the difference in pressure between the atmosphere and the lungs, including both intrapulmonary pressure and intrapleural pressure. If the intrapulmonary pressure is 760 mm Hg, we would expect the intrapleural pressure to typically be lower than the intrapulmonary pressure.

Given the choices of 764 mm Hg and 756 mm Hg, the intrapleural pressure would more likely be 756 mm Hg, because intrapleural pressure is usually negative relative to intrapulmonary pressure, facilitating the movement of air into the lungs. This pressure difference is essential for normal inspiration and expiration.