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Respiratory notes
- 1. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 1
Structure and Function of the
Pulmonary System
- 2. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 2
Structures of the Pulmonary
System
Airways
Pulmonary circulation
Chest wall
Lungs
Lobes (three on right, two on left)
Segments
Lobules
Mediastinum
- 3. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 3
Structures of the Pulmonary
System (cont’d)
- 4. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 4
Structures of the Pulmonary
System (cont’d)
Conducting airways:
Upper airways:
• Nasopharynx
• Oropharynx
Larynx
• Connects upper and lower airways
Lower airways:
• Trachea
• Bronchi
• Terminal bronchioles
- 5. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 5
Structures of the Pulmonary
System (cont’d)
- 6. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 6
Structures of the Pulmonary
System (cont’d)
Gas-exchange airways:
Respiratory bronchioles
Alveolar ducts
Alveoli
• Epithelial cells:
Type I alveolar cells
– Alveolar structure
Type II alveolar cells
– Surfactant production
- 7. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 7
Structures of the Pulmonary
System (cont’d)
- 8. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 8
Structures of the Pulmonary
System (cont’d)
- 9. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 9
Pulmonary and Bronchial
Circulation
Pulmonary circulation has a lower
pressure than the systemic circulation
One-third of pulmonary vessels are filled
with blood at any given time
Pulmonary artery divides and enters the
lung at the hilus
Each bronchus and bronchiole has an
accompanying artery or arteriole
- 10. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 10
Pulmonary and Bronchial
Circulation (cont’d)
Alveolocapillary membrane
Formed by the shared alveolar and capillary
walls
Gas exchange occurs across this membrane
Pulmonary veins
Each drains several pulmonary capillaries
Dispersed randomly throughout the lung
Leave the lung at the hila and enter the left
atrium
- 11. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 11
Pulmonary and Bronchial
Circulation (cont’d)
- 12. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 12
Chest Wall and Pleura
Chest wall
Skin, ribs, and intercostal muscles
Thoracic cavity
Pleura
Serous membrane
Parietal and visceral layers
Pleural space (cavity)
Pleural fluid
- 13. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 13
Thoracic Cavity
- 14. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 14
Function of the Pulmonary System
Ventilate the alveoli
Diffuse gases into and out of the blood
Perfuse the lungs so the body receives
oxygen
- 15. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 15
Function of the Pulmonary System
(cont’d)
Ventilation
Mechanical movement of gas or air into and
out of the lungs
Minute volume
• Ventilatory rate multiplied by the volume of air per
breath
Alveolar ventilation
- 16. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 16
Ventilation
Respiratory center
• Dorsal respiratory
group
• Ventral respiratory
group
• Pneumotaxic center
• Apneustic center
Peripheral
chemoreceptors
Lung receptors:
• Irritant receptors
• Stretch receptors
• J receptors
Chemoreceptors:
• Central
chemoreceptors
• Peripheral
chemoreceptors
Neurochemical control
- 17. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 17
Neurochemical Respiratory Control
- 18. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 18
Mechanics of Breathing
Major and accessory muscles:
Major muscles of inspiration:
• Diaphragm
• External intercostals
Accessory muscles of inspiration:
• Sternocleidomastoid muscle
• Scalene muscles
Accessory muscles of expiration:
• Abdominal intercostal muscles
• Internal intercostal muscles
- 19. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 19
Muscles of Ventilation
- 20. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 20
Mechanics of Breathing
Alveolar surface tension and ventilation
Function of surfactant
Elastic properties of the lung and chest
wall:
Elastic recoil
Compliance
Airway resistance
Work of breathing
- 21. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 21
Mechanics of Breathing
(cont’d)
- 22. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 22
Gas Transport
Four steps
Ventilation of the lungs
Diffusion of oxygen from the alveoli into the
capillary blood
Perfusion of systemic capillaries with
oxygenated blood
Diffusion of oxygen from systemic capillaries
into the cells
Diffusion of CO2 occurs in reverse order
- 23. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 23
Measurement of Gas Pressure
Barometric pressure
Partial pressure
Partial pressure of water vapor
- 24. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 24
Measurement of Gas Pressure
(cont’d)
- 25. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 25
Gas Transport
Distribution of ventilation and perfusion
Gravity and alveolar pressure
Ventilation-perfusion ratio
- 26. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 26
Gas Transport (cont’d)
Oxygen transport
Diffusion across the alveolocapillary membrane
Determinants of arterial oxygenation:
• Hemoglobin binding
• Oxygen saturation
Oxyhemoglobin association and dissociation
• Oxyhemoglobin dissociation curve
• Bohr effect
- 27. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 27
Measurement of Gas Pressure
- 28. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 28
Gas Transport
Carbon dioxide transport
Dissolved in plasma
Bicarbonate
Carbamino compounds
Haldane effect
- 29. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 29
Control of Pulmonary Circulation
Hypoxic pulmonary vasoconstriction
Caused by low alveolar paO2
Blood is shunted to other, well-ventilated
portions of the lungs
• Provides better ventilation and perfusion matching
• If hypoxia affects all segments of the lungs, the
vasoconstriction can result in pulmonary
hypertension
- 30. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 30
Control of Pulmonary Circulation
(cont’d)
Acidemia also causes pulmonary artery
constriction
- 31. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 31
Tests of Pulmonary Function
Spirometry
Diffusion capacity
Residual volume
Functional reserve capacity (FRC)
Total lung capacity
Arterial blood gas analysis
Chest radiographs
- 32. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 32
Aging and the Pulmonary System
Loss of elastic recoil
Stiffening of the chest wall
Alterations in gas exchange
Increases in flow resistance
Decreased exercise tolerance
- 33. Mosby items and derived items © 2012 Mosby, Inc., an imprint of Elsevier Inc. 33
Aging and the Pulmonary System
(cont’d)