1. The Respiratory System
Chapter 23, part 3
The Respiratory System

2. SECTION 23-7 Pulmonary Ventilation

3. Pulmonary Ventilation
The physical movement of air into and out of the lungs

4. Air movement Movement of air depends upon Boyle’s Law
Pressure and volume inverse relationship
Volume depends on movement of diaphragm and ribs
Pressure and airflow to the lungs
Compliance – an indication of the expandability of the lungs

5. Figure 23.14 Respiratory Pressure and Volume Relationships
Figure 23.14a, b

6. Pressure changes during inhalation and exhalation
Relationship between intrapulmonary pressure and atmospheric pressure determines direction of air flow
Intrapleural pressure maintains pull on lungs
Pressure in the space between parietal and visceral pleura

7. Figure 23.15 Mechanisms of Pulmonary Ventilation

8. Figure 23.15 Mechanisms of Pulmonary Ventilation
Figure 23.15a-d

9. Respiratory cycle Single cycle of inhalation and exhalation
Amount of air moved in one cycle = tidal volume
PLAY
Animation: Pulmonary Ventilation

10. Figure 23.16 Pressure Changes during Inhalation and Exhalation

11. Mechanisms of breathing
Quiet breathing (eupnea)
Diaphragm and external and internal intercostals muscles
Forced breathing (hyperpnea)
Accessory muscles

12. Figure 23.17 The Respiratory Muscles
Figure 23.17a-d

13. Respiratory volumes Alveolar volume
Amount of air reaching the alveoli each minute
Tidal Volume (VT)
Amount of air inhaled or exhaled with each breath
Vital capacity
Tidal volume plus expiratory and inspiratory reserve volumes
Residual volume
Air left in lungs after maximum exhalation

14. Figure 23.18 Respiratory Volumes and Capacities

15. SECTION Gas Exchange

16. The gas laws Daltons Law and partial pressure
Individual gases in a mixture exert pressure proportional to their abundance
Diffusion between liquid and gases (Henry’s law)
The amount of gas in solution is directly proportional to their partial pressure

17. Figure 23.19 Henry’s Law and the Relationship between Solubility and Pressure

18. Figure 23.19 Henry’s Law and the Relationship between Solubility and Pressure
Figure 23.19a-c

19. Diffusion and respiratory function
Gas exchange across respiratory membrane is efficient due to:
Differences in partial pressure
Small diffusion distance
Lipid-soluble gases
Large surface area of all alveoli
Coordination of blood flow and airflow