1. Mechanics of Breathing17

2. About this Chapter
The respiratory system
Gas laws
Ventilation

3. Respiratory System
Exchange of gases between the atmosphere and the blood
Homeostatic regulation of body pH
Protection from inhaled pathogens and irritating substances
Vocalization

4. Principles of Bulk Flow
Flow from regions of higher to lower pressure
Muscular pump creates pressure gradients
Resistance to flow
Diameter of tubes

5. Respiratory System Overview of external and cellular respiration
Figure 17-1

6. Respiratory System Conducting system Alveoli
Bones and muscle of thorax

7. Respiratory System
Figure 17-2a

8. Muscles Used for Ventilation
Figure 17-2b

9. The Respiratory System
The relationship between the pleural sac and the lung
Figure 17-3

10. Branching of Airways
Figure 17-2e

11. Branching of the Airways
Figure 17-4

12. Alveolar Structure
Figure 17-2g

13. Pulmonary Circulation
Right ventricle  pulmonary trunk  lungs  pulmonary veins  left atrium
PLAY
Animation: Respiratory System: Anatomy Review

14. Gas Laws

15. Gas Laws
Pgas = Patm  % of gas in atmosphere

16. Boyle’s Law
Gases move from areas of high pressure to areas of low pressure
Figure 17-5

17. Spirometer
Figure 17-6

18. Lungs Volumes and Capacities
Figure 17-7

19. Conditioning Warming air to body temperature Adding water vapor
Filtering out foreign material

20. Ciliated Respiratory Epithelium
Figure 17-8

21. Air Flow
Flow  P/R
Alveolar pressure or intrapleural pressure can be measured
Single respiratory cycle consists of inspiration followed by expiration

22. Movement of the Diaphragm
Figure 17-9a

23. Movement of the Diaphragm
Figure 17-9b

24. Movement of the Diaphragm
Figure 17-9c

25. Movement of the Rib Cage during Inspiration
Figure 17-10a

26. Movement of the Rib Cage during Inspiration
Figure 17-10b

27. Pressure Changes during Quiet Breathing
Figure 17-11

28. Pressure in the Pleural Cavity
Figure 17-12a

29. Pressure in the Pleural Cavity
Pneumothorax results in collapsed lung that can not function normally
Figure 17-12b

30. Compliance and Elastance
Compliance: ability to stretch
High compliance
Stretches easily
Low compliance
Requires more force
Restrictive lung diseases
Fibrotic lung diseases and inadequate surfactant production
Elastance: returning to its resting volume when stretching force is released

31. Law of LaPlace
Surface tension is created by the thin fluid layer between alveolar cells and the air
Figure 17-13

32. Surfactant More concentrated in smaller alveoli
Mixture containing proteins and phospholipids
Newborn respiratory distress syndrome
Premature babies
Inadequate surfactant concentrations

33. Air Flow
PLAY
Animation: Respiratory System: Pulmonary Ventilation

34. Ventilation Total pulmonary ventilation and alveolar ventilation
Total pulmonary ventilation = ventilation rate  tidal volume
150 mL
350
2700 mL
2200 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
End of inspiration
Inhale 500 mL
of fresh air
(tidal volume).
Dead space filled
with stale air
KEY
Only
350 mL
reaches
alveoli.
The first exhaled
air comes out of
the dead space.
Only 350 mL leaves
the alveoli.
Dead space
is filled with
fresh air.
The first 150 mL
of air into the
alveoli is stale
air from the
dead space.
At the end of
expiration, the
dead space is
filled with
“stale” air from
500 mL
Atmospheric
air
Exhale 500 mL 1 2 3 4
Figure 17-14

35. Ventilation Figure 17-14, step 1 Dead space filled with fresh air 150mL
2700 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
KEY 1
End of inspiration
Figure 17-14, step 1

36. Ventilation Figure 17-14, steps 1–2 Dead space filled with fresh air
150 mL
2700 mL
2200 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
End of inspiration
KEY
The first exhaled
air comes out of
the dead space.
Only 350 mL leaves
the alveoli.
350
Exhale 500 mL
(tidal volume). 1 2
Figure 17-14, steps 1–2

37. Ventilation Figure 17-14, steps 1–3 150 mL 2700 mL 2200 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
End of inspiration
Dead space filled
with stale air
KEY
The first exhaled
air comes out of
the dead space.
Only 350 mL leaves
the alveoli.
At the end of
expiration, the
dead space is
filled with
“stale” air from
alveoli.
350
Exhale 500 mL
(tidal volume). 1 2 3
Figure 17-14, steps 1–3

38. Ventilation Figure 17-14, steps 1–4 150 mL 350 2700 mL 2200 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
End of inspiration
Inhale 500 mL
of fresh air
(tidal volume).
Dead space filled
with stale air
KEY
Only
350 mL
reaches
alveoli.
The first exhaled
air comes out of
the dead space.
Only 350 mL leaves
the alveoli.
Dead space
is filled with
fresh air.
The first 150 mL
of air into the
alveoli is stale
air from the
dead space.
At the end of
expiration, the
dead space is
filled with
“stale” air from
500 mL
Atmospheric
air
Exhale 500 mL 1 2 3 4
Figure 17-14, steps 1–4

39. Ventilation Figure 17-14, steps 1–5 150 mL 350 2700 mL 2200 mL
Dead space filled with fresh air
PO2 = 160 mm Hg
PO2 ~ 100 mm Hg ~
Respiratory
cycle in
an adult
End of inspiration
Inhale 500 mL
of fresh air
(tidal volume).
Dead space filled
with stale air
KEY
Only
350 mL
reaches
alveoli.
The first exhaled
air comes out of
the dead space.
Only 350 mL leaves
the alveoli.
Dead space
is filled with
fresh air.
The first 150 mL
of air into the
alveoli is stale
air from the
dead space.
At the end of
expiration, the
dead space is
filled with
“stale” air from
500 mL
Atmospheric
air
Exhale 500 mL 1 2 3 4
Figure 17-14, steps 1–5

40. Ventilation
Alveolar ventilation = ventilation rate  (tidal volume – dead space volume)

41. Ventilation

42. Ventilation

43. Ventilation
Effects of changing alveolar ventilation on PO2 and PCO2 in the alveoli
Figure 17-15

44. Ventilation

45. Ventilation Local control matches ventilation and perfusion
Figure 17-16a

46. Ventilation
Figure 17-16b

47. Ventilation
Figure 17-16c

48. Ventilation Auscultation = diagnostic technique
Obstructive lung diseases
Asthma
Emphysema
Chronic bronchitis

49. Summary Respiratory system Gas Laws: Dalton’s law and Boyle’s law
Cellular respiration, external respiration, respiratory system, upper respiratory tract, pharynx, and larynx
Lower respiratory tract, trachea, bronchi, bronchioles, alveoli, Type I and Type II alveolar cells
Diaphragm, intercostal muscles, lung, pleural sac, and plural fluid
Gas Laws: Dalton’s law and Boyle’s law

50. Summary
Ventilation
Tidal volume, vital capacity, residual volume, and respiratory cycle
Alveolar pressure, active expiration, intrapleural pressures, compliance, elastance, surfactant, bronchoconstriction, and bronchodilation
Total pulmonary ventilation, alveolar ventilation, hyperventilation, and hypoventilation