How is air moved in and out of the lungs?

The movement of air in and out of the lungs primarily occurs through the action of the diaphragm and intercostal muscles. The diaphragm, a dome-shaped muscle located at the base of the chest, plays a crucial role in respiration. When it contracts, it flattens and moves downward, increasing the volume of the thoracic cavity, which in turn lowers the pressure inside the lungs relative to the atmospheric pressure. This pressure difference allows air to flow into the lungs.

The intercostal muscles, situated between the ribs, also assist in this process. When these muscles contract, they lift the ribcage upwards and outwards, further expanding the thoracic cavity and helping to facilitate inhalation. During exhalation, the diaphragm relaxes, and the elastic recoil of the lungs, combined with the downward movement of the ribcage, pushes air out of the lungs.

This coordinated action of the diaphragm and intercostal muscles is essential for effective ventilation, allowing for adequate exchange of oxygen and carbon dioxide during the breathing process.