The Respiratory System Review

5. Portion of the lung where gas exchange occurs at the alveolar level.
8. Small airways lacking cartilage that regulate airflow resistance.
9. Immune cells that remove debris and pathogens from alveoli.
11. Opposition to airflow within the respiratory tract.
13. Collapse of alveoli leading to impaired gas exchange.
16. Low arterial oxygen level (PaO₂).
18. Cartilage that prevents aspiration during swallowing.
20. Ventilated air that does not participate in gas exchange.
21. Perfusion without ventilation leading to severe hypoxemia.
23. Microscopic air sacs that serve as the primary site of gas exchange.
24. Movement of air into and out of the lungs.
25. Volume of air remaining after normal exhalation.
30. Muscles recruited during increased work of breathing.
31. Motile structures that propel mucus toward the upper airway.
32. Substance that improves lung compliance and prevents alveolar collapse.
33. Passive movement of gases across the alveolar-capillary membrane.
34. Sensors that regulate ventilation based on CO₂, O₂, and pH.
36. Cartilage-supported airway that conducts air from the larynx to the bronchi.
37. Mechanism that clears mucus and trapped particles from the airways.
39. Total volume of air moved per minute (VT × rate).

1. Brainstem center that controls automatic breathing.
2. Blood flow through pulmonary capillaries for gas exchange.
3. Airways that transport and condition air without participating in gas exchange.
4. Volume of air reaching alveoli for gas exchange per minute.
6. Primary muscle of inspiration responsible for most tidal breathing.
7. Pressure exerted by a single gas within a mixture.
10. Circulatory pattern that bypasses the lungs before birth.
12. Condition caused by surfactant deficiency, typically in premature infants.
14. Conducting airways where no gas exchange occurs (~2.2 mL/kg).
15. Measure of lung expansion relative to pressure change.
16. Elevated arterial carbon dioxide level (PaCO₂).
17. Volume of air inhaled or exhaled during normal breathing.
19. Cells that produce surfactant to reduce alveolar surface tension.
22. Muscular passageway conducting air from nasal/oral cavities to the larynx.
26. Exchange of oxygen and carbon dioxide between alveoli and blood.
27. Point of tracheal bifurcation that is highly sensitive and triggers coughing.
28. Ratio Relationship between airflow and blood flow in the lungs.
29. Thin alveolar cells responsible for diffusion of gases.
35. Major airways branching from the trachea into each lung.
38. Structure that maintains airway patency and enables phonation.