intrapleural and intrapulmonary pressure

[yoyohomieg5432]

I'm slightly confused on how these two pressures are used for respiration. generally, the intrapulmonary pressure is slightly less than atmospheric, which allows air to flow into the lungs, correct?

What is the role of the intrapleural pressure? Is this what causes air to move in and out? I.e. when diaphragm contracts, pleural volume increases, causing a decrease in intrapleural pressure. As a result the force on the lungs is less which allows more air to be pushed in from the outside? And when the diaphragm contracts, intrapleural pressure increases, causing an increased force on the lungs, pushing air out.

Is this reasoning correct? Essentially the intrapleural pressure does everything. the intrapulmonary pressure is just present so that the lungs don't completely collapse due to forces from the intrapleural pressure?

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[rfvbnmju]

Let's see if I get this right..someone double check my reasoning.

The intrapleural pressure is generally negative.
Visceral pleural covers lungs and parietal pleura covers chest cavity.
Pressure between them needs to be negative so those two pleurals are pulled together giving the max volume of the abdominal cavity. Alveolar pressure is very low and the alveolar sacs would collapse if the intrapleural pressure is positive. (There's also surfactants in the alveolar space to keep the cohesion of water moisture from collapsing the alveolar sacs also) When the lung is punctured, the intrapleural pressure becomes positive and this positive pressure collapses the lung.

When your diaphragm contracts, the chest cavity volume increases. From Boyle's law, if volume goes up, then the pressure inside the lungs goes down. Since Patm>Plungs, air will flow in.

The opposite happens in expiation.
It's a combination of both that causes air to flow in and out.