When you breathe does lungs get bigger and smaller?

Yes, the lungs get bigger and smaller when you breathe.

When you inhale, the diaphragm and intercostal muscles contract, pulling the lungs down and out. This creates a negative pressure in the lungs, which draws air in through the nose and mouth.

As you exhale, the diaphragm and intercostal muscles relax, pushing the lungs back up and in. This creates a positive pressure in the lungs, which forces air out through the nose and mouth.

The lungs are elastic, so they can stretch and recoil with each breath. The amount of air that can be moved in and out of the lungs depends on the elasticity of the lungs, the strength of the respiratory muscles, and the resistance of the airway.