Respiratory System Physiology: Key Concepts and Facts

Respiratory System Physiology Q&A

1. Lung Mechanics

Question: What two factors cause the lungs to have a constant tendency to collapse?
Answer: Elastic fibers around the alveoli and surface tension in the alveolar water.

2. Sound Production

Question: What is the organ primarily responsible for sound production?
Answer: Larynx.

3. Tidal Volume

Question: What is the volume of a typical tidal inhalation?
Answer: 500 mL.

4. Gas Exchange Distance

Question: Which of these is closest to the approximate distance between blood plasma and air?
Answer: 1 µm.

5. Alveolar Function

Question: What is the function of type 2 alveolar cells?
Answer: Secrete surfactant.

6. Pleural Membranes

Question: What do we call the membrane around the lungs which is attached to the body wall?
Answer: Parietal pleura.

7. Tracheal Cilia

Question: What is the purpose of the cilia on the cells lining the trachea and bronchi?
Answer: To move mucus towards the pharynx.

8. Boyle's Law

Question: How will increasing the volume of a sealed container affect the pressure in the container?
Answer: It will decrease.

9. Chemoreceptors

Question: Where are the peripheral chemoreceptors which help determine respiratory rate?
Answer: In the carotid arteries and aorta.

10. Airflow Dynamics

Question: If the air pressure inside a person's alveoli is 758 mmHg, and the air pressure outside the body is 754 mmHg, which way will air move?
Answer: Out of the lungs.

11. Lung Collapse

Question: Which of these can cause lung collapse?
Answer: Air entering the pleural cavity from outside.

12. Surfactant Deficiency

Question: Would lack of surfactant make it harder to inhale or exhale?
Answer: Inhale.

13. Respiratory Regulation

Question: In a healthy person, what effect would an increase in plasma P(O2) from 100 mmHg to 120 mmHg have on respiratory rate?
Answer: It would not be affected.

14. Alveolar Pressure

Question: At the end of exhalation in Death Valley, what pressure would you expect in the alveoli?
Answer: 780 mmHg.

15. Alveolar Gas Levels

Question: Which of these is closest to the typical P(CO2) of alveolar air?
Answer: 40 mmHg.

16. Pulmonary Circulation

Question: At which of these locations is plasma P(O2) increasing?
Answer: Pulmonary capillaries.

17. CO2 Transport

Question: Why does CO2 move from extracellular fluid into the blood plasma?
Answer: CO2 is moving down its partial pressure gradient.

18. Hemoglobin Capacity

Question: What is the maximum number of oxygen molecules which can be carried by one hemoglobin molecule?
Answer: Four.

19. Bicarbonate Conversion

Question: Of 100 CO2 molecules entering the plasma, how many become bicarbonate ions?
Answer: 70%.