FIG. 3 in Aristotle on the anatomy of the heart and lungs (HA 1.17): new insights from a multidisciplinary approach

FIG. 3. — The process of breathing for gas exchange and the pressure change in the pleural cavity: A, during inspiration, air enters the lungs (light blue arrow), the negative pressure inside of the pleural cavity (black arrowhead) decreases and the thoracic cavity expands (orange arrows), while the lungs increase in volume;B, in exhalation, as air comes out of the lungs (light blue arrow) the pressure inside the pleural cavity (black arrowhead) increases, the thoracic cavity contracts (orange arrows), and the volume of the lungs reduces. Credit: image by Mariana Ruiz Villareal [LadyofHats], modified and taken from https://commons.wikimedia.org/, last consultation on 4 December 2023.