AP151 Respiratory System Study Guide
RELAVENT READING:
TEXTBOOK CHAPTER 16
 Pg 533-544
 Pg 547-563 (skip “disorders caused by high partial pressures)
 Pg565-66 (start with chloride shift, end at acid base balance)
 Figure 16.22, 16.26, 16.28, 16.29, 16.33, 16.34, 16.38, 16.39, 16.40, and Table 16.9 are great!
VISUAL ANALOGY GUIDE
 Pg 84-87
 Pg 88-99: these are some nice to the point summaries.
MAIN GOALS/OBJECTIVES
 Describe the mechanics of ventilation and the factors that influence it
 Describe pulmonary blood flow and how perfusion is matched to ventilation in the lungs.
 Describe how oxygen is transported and the diffusion of O2 from alveolar air, to blood, to
interstitial fluid, including the factors that influence oxygen loading and unloading on Hb.
 Describe how carbon dioxide is transported and the diffusion of O2 from interstitial fluid, to
blood to alveolar air
 Describe how the nervous system regulates breathing/ventilation
PRACTICE QUESTIONS
Describe the mechanics of ventilation and the factors that influence it
1. What is ventilation?
2. Describe the relationship between pressures and the direction of air flow.
3. What does the term intrapulmonary (alveolar) pressure refer to? What is the typical range of
intrapulmonary pressure during quiet (resting) breathing?
4. What does the term atmospheric pressure refer to? What is average atmospheric pressure at
sea level?
5. What is intrapleural pressure?
6. Which pressure (from above questions) is always lower then atmospheric pressure?
7. Why is it important that intrapleural pressure always be “negative”?
8. What would happen if intrapleural pressure was disrupted and it became greater then
intrapulmonary pressure?
9. During quiet, normal inhalation what muscle is responsible for roughly 70-75% of the air
movement? What muscles assist the diaphragm normal, quiet inhalation and accounts for the
rest of the filling of the lungs with air?
10. During inhalation does the diaphragm relax or contract? How does its position change?
11. During exhalation does the diaphragm relax or contract? How does its position change?
12. What does it mean when we refer to quiet inhalation as being active and expiration as being
passive?
13. What are the factors that cause the lungs/thoracic cavity to passively return to its resting
volume?
14. What happens to the volume of the thoracic cavity/lungs during inspiration? Expiration?
15. Why and when does intrapulmonary pressure go down? Up?
16. Explain in a step by step fashion the events that result in inhalation and Exhalation.
17. How is forced ventilation (exhalation/inhalation) different from quiet breathing (in general)?
Describe pulmonary blood flow and how perfusion is matched to ventilation in the lungs.
18. Describe the blood pressure within the pulmonary circuit.
19. What happens within the alveoli if pulmonary blood pressure gets too high? What effect does
that have on gas exchange?
20. How do bronchioles respond to high levels of alveolar CO2? Low levels of carbon dioxide? What
consequence do these responses have on alveolar ventilation (i.e., bring air into alveoli)
21. How do pulmonary blood vessels respond to high levels of alveolar oxygen? Low levels of
alveolar oxygen? What consequence does this have on oxygen acquisition?
22. What is meant by saying that perfusion is matched to ventilation in the lungs.
Gas Exchange
23. What is external respiration?
24. What direction does oxygen and carbon dioxide diffuse during the process of external
respiration.
25. Describe the partial pressure gradients of CO2 and O2 between pulmonary capillary blood and
alveoli
26. Why is diffusion/gas exchange in the lungs so efficient (list 4-5 reasons)?
27. Approximately, what percent of all oxygen is transported in plasma? On hemoglobin?
28. What substance must oxygen pass through as it diffuses between alveoli and hemoglobin?
29. What transportation process causes exchange of CO2 and O2 in the systemic capillaries?
30. What are the partial pressures of oxygen and carbon dioxide in the: blood arriving at the
systemic capillaries (peripheral tissues), within the interstitial fluid surrounding the systemic
capillaries, and blood leaving the systemic capillaries?
31. Do the partial pressure values of CO2 and O2 reflect the total gas levels in blood or just the
levels of those gasses in plasma?
Describe how oxygen is transported and diffusion
32. What are the two ways that oxygen is transported through blood? Approximately what percent
of oxygen is transported through each mechanism?
33. What is the blood saturation of oxygen for a healthy person at rest, at sea level?
34. Does hyperventilation of a healthy individual, at rest, at sea level significantly increase oxygen
saturation of blood?
35. Be able to read/interpret the hemoglobin saturation curve so you can determine oxygen
saturation, loading, and unloading of hemoglobin at different partial pressures.
36. What effect would increase pH have on the amount of oxygen unloaded from Hb? What effect
would decreased pH have on oxygen unloading from Hb?
37. What effect would increase temperature have on oxygen unloading from Hb? Temperature
decreases?
38. Why does oxygen leave Hb and blood at the systemic tissues?
Describe how co2 is transported and diffusion
39. Why does CO2 diffuse into the blood of systemic capillaries?
40. What are the three ways that carbon dioxide is transported through blood? What percent of all
carbon dioxide is transported by each of the three mechanisms?
41. Describe the chemical reaction that results in the production of bicarbonate from the entrance
of CO2 into blood?
42. Describe the events that result in bicarbonate forming CO2 in the lungs.
43. Describe the chemical reactions that occur when carbon dioxide enters blood that leads to pH
changes within blood?
44. As the amount of CO2 in blood increases what happens to the pH of blood?
45. As the amount of CO2 in blood decreases what happens to the pH of blood?
46. What is the chloride shift?
Describe how the nervous system regulates breathing/ventilation
47. What two parts of the brainstem are involved with the regulation of breathing?
48. List the four specific centers of the brainstem that regulate breathing?
49. Where is the DRG and what is its role in controlling breathing?
50. Where is the VRG and what is its role in controlling breathing?
51. How do the apneustic and pneumotaxic relate to the activity of the DRG and VRG—in general;
keep it simple?
52. What and where are the central receptors and what do they detect/respond to for the purpose
of regulating breathing?
53. What and where are the two peripheral receptors and what do they detect/respond to for the
purpose of regulating breathing? What cranial nerves are involved in each?
54. Are the ventilation control centers more sensitive to changes in oxygen or carbon dioxide?
55. How low must blood oxygen levels get before they result in significant changes in respiration?
56. How does hyperventilation influence CO2, pH, and O2 levels of blood and the respiratory drive?
57. Describe the changes in respiration that would occur due to hypercapnia and hypocapnia to
maintain normal blood gas concentrations/levels
58. Describe how the chemoreceptor reflex changes respiratory rate
59. If discussed in class, describe the
60. Hering-Breuer reflexes
SPECIAL TOPICS
61. If discussed in class, explain how respiratory physiology relates to the phenomenon of
“shallow-water blackouts/drowning” and/or Cheynes-stokes breathing.