What is intrapleural pressure?

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Multiple Choice

What is intrapleural pressure?

Intrapleural pressure is the pressure inside the pleural cavity, the thin space between the lungs’ visceral pleura and the chest wall’s parietal pleura. It is normally subatmospheric (negative relative to atmospheric pressure) because the chest wall tends to pull outward while the lungs tend to recoil inward. That negative pressure keeps the two membranes pulled together and creates a transpulmonary pressure that keeps the lungs inflated. During inspiration, the diaphragm and intercostal muscles expand the chest, making the intrapleural pressure even more negative, which helps expand the lungs. During expiration, it becomes less negative as the chest recoils. If the pleural space is exposed to atmospheric pressure (as in a chest wound), the negative pressure is lost and the lungs can collapse because the driving force keeping them expanded vanishes.

Intrapleural pressure is the pressure inside the pleural cavity, the thin space between the lungs’ visceral pleura and the chest wall’s parietal pleura. It is normally subatmospheric (negative relative to atmospheric pressure) because the chest wall tends to pull outward while the lungs tend to recoil inward. That negative pressure keeps the two membranes pulled together and creates a transpulmonary pressure that keeps the lungs inflated. During inspiration, the diaphragm and intercostal muscles expand the chest, making the intrapleural pressure even more negative, which helps expand the lungs. During expiration, it becomes less negative as the chest recoils. If the pleural space is exposed to atmospheric pressure (as in a chest wound), the negative pressure is lost and the lungs can collapse because the driving force keeping them expanded vanishes.

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