What muscle is used during pulmonary ventilation to bring in and push out air? A. Diaphragm B. Sphincters C. Pleura D. Lungs

The muscle used during pulmonary ventilation to bring in and push out air is the Diaphragm (A).

Here's a step-by-step explanation:

1. During inhalation, the diaphragm contracts and moves downward. This increases the space in your chest cavity, into which your lungs expand.

2. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.

3. As your lungs expand, air is sucked in through your nose or mouth. The air travels down your windpipe and into your lungs.

4. During exhalation, the 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.

5. As the space in the chest cavity gets smaller, air rich in carbon dioxide is forced out of your lungs and windpipe, and then out of your nose or mouth.