System Function: Respiratory - Massage and Bodywork Licensing Examination Mblex

1. What is the function of pleural fluid?

   Reduces friction and helps maintain lung adherence to thorax. Lubricates pleural surfaces for effortless lung expansion and creates surface tension to prevent lung collapse.

2. Which alveolar cell type forms most of the alveolar wall for diffusion?

   Type I alveolar cells (type I pneumocytes). Squamous cells provide a thin, permeable barrier maximizing efficiency of gas diffusion across the alveoli.

3. Which alveolar cell type produces surfactant?

   Type II alveolar cells (type II pneumocytes). Specialized epithelial cells secrete the lipid-protein complex essential for lung compliance and stability.

4. What is the relationship between thoracic volume and intrapulmonary pressure?

   Inverse relationship: volume increases, pressure decreases. Follows Boyle's law, where expanding volume reduces gas pressure, driving inspiration and expiration mechanics.

5. Which brainstem center is the primary driver of the basic breathing rhythm?

   Medulla oblongata (respiratory centers). Generates rhythmic neural impulses to respiratory muscles, coordinating involuntary breathing patterns.

6. Which muscles are most associated with forced expiration?

   Internal intercostals and abdominal muscles. Actively decrease thoracic volume to increase pressure and expel air when passive elastic recoil is insufficient.

7. What is the primary function of alveolar macrophages?

   Phagocytize pathogens and particulate matter in alveoli. Immune cells engulf and remove inhaled debris, protecting alveolar integrity and preventing inflammation.

8. What is surfactant, and what is its primary effect in the alveoli?

   Phospholipid mixture that lowers surface tension to prevent collapse. Reduces alveolar wall tension, stabilizing small air sacs and preventing atelectasis during exhalation.

9. Which structure is known as the voice box?

   Larynx. Houses vocal cords that vibrate to produce sound, serving phonation while protecting the lower respiratory tract.

10. What is pulmonary ventilation?

    Movement of air into and out of the lungs. Essential for delivering oxygen to alveoli and expelling carbon dioxide, maintaining gas gradients for exchange.

11. What is the conducting zone of the respiratory tract?

    Air passages that conduct, warm, humidify, and filter air. Prepares inhaled air for gas exchange by conditioning it without participating in diffusion itself.

12. What is the function of the tracheal C-shaped cartilage rings?

    Maintain airway patency while allowing esophageal expansion. Provides structural support to keep the trachea open, with the open posterior allowing flexibility for swallowing.

13. During quiet inhalation, which direction does air move relative to the lungs?

    Into the lungs as intrapulmonary pressure falls below atmospheric. Pressure gradient created by diaphragm contraction pulls air in until equilibrium with atmospheric pressure is reached.

14. What is the main site of external gas exchange in the lungs?

    Alveoli (alveolar-capillary membrane). Thin barrier allows efficient diffusion of gases between air and blood due to large surface area and proximity to capillaries.

15. Identify the correct branching order from trachea to gas exchange units.

    Trachea → bronchi → bronchioles → alveolar ducts → alveoli. Progressively smaller passages increase surface area and slow airflow, optimizing for filtration and gas exchange.

16. What is the respiratory zone of the respiratory tract?

    Structures where gas exchange occurs (alveoli). Comprises terminal bronchioles and alveoli where oxygen and carbon dioxide diffuse across membranes.

17. Which structure is the primary muscle of inspiration?

    Diaphragm. Contraction creates negative pressure in the thoracic cavity, driving the majority of inspiratory airflow during quiet breathing.

18. Which chemical change is the strongest stimulus for increased ventilation?

    Increased arterial $CO_2$ (via increased $H^+$ in cerebrospinal fluid). Central chemoreceptors detect hypercapnia-induced acidosis, triggering hyperventilation to restore pH balance.

19. What is the primary role of hemoglobin in respiratory physiology?

    Transports most oxygen in blood by reversible binding. Binds oxygen in high partial pressure areas like lungs and releases it in tissues, optimizing transport efficiency.

20. What is the function of the nasal conchae (turbinates)?

    Increase surface area to warm, humidify, and filter inspired air. Enhances contact with mucous membranes to condition air, protecting lower airways from cold, dry, or particulate-laden air.

21. What action does the diaphragm take during quiet inhalation?

    Contracts and descends (flattens). Increases thoracic volume, decreasing intrapulmonary pressure below atmospheric to facilitate air inflow.

22. What is the pleura?

    Double-layered serous membrane surrounding the lungs. Visceral layer adheres to lungs while parietal layer lines thoracic wall, facilitating smooth movement during breathing.

23. What is the function of cilia and mucus in the conducting airways?

    Mucociliary escalator: traps and moves debris toward pharynx. Cilia propel mucus-trapped particles upward for expulsion, maintaining airway cleanliness and preventing infection.

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