The respiratory system

4. The process of air entering the body through the mouth or nose.
7. The muscle that contracts to pull air into the lungs.
10. The process of releasing air from the lungs.
11. dioxide The primary waste gas released during exhalation.
12. Small blood vessels where gas exchange occurs with the alveoli.
14. The primary organ for gas exchange in the respiratory system.
15. A chronic respiratory disease that causes narrowing of the airways.
16. The smaller airways branching off the bronchi in the lungs.
17. The part of the throat that connects the mouth to the esophagus and trachea.
18. The windpipe that directs air to the lungs.

1. A lung condition that damages alveoli, reducing oxygen absorption.
2. Tiny sacs in the lungs where gas exchange occurs.
3. The cells lining the respiratory tract that produce mucus to trap particles.
5. The primary gas absorbed by the body during inhalation.
6. The two large airways that lead from the trachea to the lungs.
8. The exchange of gases between the lungs and the blood at the alveoli.
9. Small openings on plant leaves that allow for gas exchange, similar to alveoli in the lungs.
11. The system that transports oxygenated blood from the lungs to the body.
13. The cells responsible for gas exchange in the alveoli.