1  INTRODUCTION 1

  Introduction 2

  What is respiration? 2

  The need for respiration 2

  Diffusion in respiration and the circulation 3

  Timing in the circulation and respiration 3

  Basic science of respiration 3

  Drugs 9

2  STRUCTURE OF THE RESPIRATORY SYSTEM,RELATED TO FUNCTION 11

  Introduction 12

  The upper airways 12

  The intrathoracic airways 15

  Blood vessels 18

  Pulmonary hypertension 18

  The lymphatics 19

  The nerves 19

  Gross structure of the respiratory system 19

  Pleurisy 20

  The diaphragm and chest wall 20

  How breathing is brought about 22

  Embryology 23

  Air-conditioning 24

  Metabolic activity 26

  Metabolism of circulating biologically active substances 27

  Non-respiratory functions 27

3  ELASTIC PROPERTIES OF THE RESPIRATORY SYSTEM 29

  Introduction 30

  Intrapleural pressure (Ppl) 30

  Static lung compliance (CL) 31

  The effect of disease 32

  The physical basis of lung compliance 32

4  AIRFLOW IN THE RESPIRATORY SYSTEM 41

  Introduction 42

  How airflow is brought about 42

  The nature of airflow 43

  The major determinant of flow - radius 43

  Airways resistance and obstructive pulmonary disease 43

  The clinical situation 45

  Sites of airways resistance 46

  Asthma and airways smooth muscle 48

  Bronchomotor tone 49

  Pharmacological treatment of asthma 50

  Clinical definitions 50

  Bronchitis and mucus 52

  Emphysema and radial traction 53

  Intrapleural pressure and cough 54

  Clinical tests for changes in resistance 57

  Work of breathing 57

5  VENTILATION OF THE RESPIRATORY SYSTEM: THE IMPORTANCE OF ITS LACK OF UNIFORMITY IN DISEASE 61

  Introduction 62

  Spirometric abnormalities in disease 63

  Uneven distribution 64

  Dead space. 64

  Alveolar dead space in disease 65

  The Bohr equation 66

  Factors affecting physiological dead space 68

  Alveolar ventilation and respiratory exchange 68

  The alveolar gas equation 69

  Distribution of inspired gas 69

  Other factors influencing distribution 72

6  GAS EXCHANGE BETWEEN AIR AND BLOOD:DIFFUSION 77

  The path from air to tissue 78

  Lung disease and diffusion 79

  Fick's Law of Diffusion 79

  Measuring transfer factor 82

  Treating diffusion difficulties 83

  Carbon dioxide and other gases 83

7  THE PULMONARY CIRCULATION: BRINGING BLOOD AND GAS TOGETHER 85

  The functions of the pulmonary circulation 86

  The anatomy of the pulmonary circulation 86

  Matching ventilation and perfusion 89

  Distribution of blood flow through the lungs 89

  Regional differences in ventilation in the lungs 94

  Ventilation/perfusion matching and its effect on blood

  O2 and CO2 content 95

  Shunt 97

8  CARRIAGE OF GASES BY THE BLOOD AND ACID/BASE BALANCE 99

  Introduction 100

  Oxygen transport 100

  Dissolved oxygen: do we really need Hb and why

  keep it in red cells? 108

  Carbon dioxide transport 109

  Acid-base balance 113

9  CHEMICAL CONTROL OF BREATHING 119

  Introduction 120

  Oxygen lack 120

  Carbon dioxide excess 125

10  NERVOUS CONTROL OF BREATHING 129

  Introduction 130

  The rhythm generator 131

  Pattern of breathing in COPD 132

  The respiratory 'centres' 133

  The medullary groups 133

  Conscious control of breathing 134

  Respiratory muscle innervation 135

  Neuromuscular disorders 137

  Vagal reflexes 137

  Dyspnoea 140

  Other reflexes 140

11  LUNG FUNCTION TESTS: MEASURING DISABILITY 143

  Introduction 144

  Spirometry 144

  Flow measurements 145

  Plethysmography 145

  Lung mechanics 146

  Transfer factor (diffusing capacity) 147

  Blood gases 148

  Gas washouts 148

  Exercise testing 150

  Challenge tests 151

  Appendix: some basic science 153

Glossary 159

Index 165