how does our ribs and diaphragm enable breathing in and out to occur?
As we inhale, our diaphragm contracts and moves downward. This increases the space in our chest cavity, into which our lungs expand. The intercostal muscles between our ribs also help to enlarge the chest cavity. They contract to pull our rib cage both upward and outward when we inhale.
When we breathe out, our diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles between the ribs also relax to reduce the space in the chest cavity.