1. Lungs Occupy most of the thoracic cavity
Apex is near the clavicle (superior portion)
Base rests on the diaphragm (inferior portion)
Each lung is divided into lobes by fissures
Left lung – two lobes
Right lung – three lobes
Slide 13.12a
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2. Lungs
Figure 13.4b
Slide 13.12b
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3. Coverings of the Lungs
Pulmonary (visceral) pleura covers the lung surface
Parietal pleura lines the walls of the thoracic cavity
Pleural fluid fills the area between layers of pleura to allow gliding
Slide 13.13
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4. Respiratory Tree Divisions
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioli
Terminal bronchioli
Slide 13.14
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5. Bronchioles Smallest branches of the bronchi Figure 13.5a Slide 13.15a
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6. Bronchioles All but the smallest branches have reinforcing cartilage
Figure 13.5a
Slide 13.15b
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7. Bronchioles Terminal bronchioles end in alveoli Figure 13.5a
Slide 13.15c
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8. Respiratory Zone Structures Site of gas exchange
Respiratory bronchioli
Alveolar duct
Alveoli
Site of gas exchange
Slide 13.16
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9. Alveoli Structure of alveoli Alveolar duct Alveolar sac Alveolus
Gas exchange takes place within the alveoli in the respiratory membrane
Slide 13.17
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10. Respiratory Membrane (Air-Blood Barrier)
Thin squamous epithelial layer lining alveolar walls
Pulmonary capillaries cover external surfaces of alveoli
Slide 13.18a
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11. Respiratory Membrane (Air-Blood Barrier)
Figure 13.6
Slide 13.18b
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12. Gas Exchange Gas crosses the respiratory membrane by diffusion
Oxygen enters the blood
Carbon dioxide enters the alveoli
Macrophages add protection
Surfactant coats gas-exposed alveolar surfaces
Slide 13.19
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13. Events of Respiration
Pulmonary ventilation – moving air in and out of the lungs
External respiration – gas exchange between pulmonary blood and alveoli
Slide 13.20a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

14. Events of Respiration
Respiratory gas transport – transport of oxygen and carbon dioxide via the bloodstream
Internal respiration – gas exchange between blood and tissue cells in systemic capillaries
Slide 13.20b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings