Essential Fluid, Electrolyte and pH Homeostasis

List of tables xvii

Preface xix

Acknowledgements xxi

Part 1: Background theory and basic concepts.

Section 1.i Introduction and overview 3

Section 1.ii Water 8

Section 1.iii Solutions: concentrations and colligative properties of solutes 12

Section 1.iv Self-assessment exercise 1.1 16

Section 1.v Acids and bases 18

Section 1.vi Buffers and the Henderson-Hasselbalch equation 23

Section 1.vii Self-assessment exercise 1.2 26

Section 1.viii Body fluids and their composition: overview 28

Section 1.ix Fluid balance: (a) between fluid compartments and (b) intake and loss 34

Section 1.x Ionic composition and electrical neutrality 39

Section 1.xi Water and ion distribution between compartments 1: Physical chemistry 43

Section 1.xii Water and ion distribution between compartments 2: Physiology 50

Section 1.xiii Osmoregulation: solvent and solute balance 55

Section 1.xiv Self-assessment exercise 1.3 60

Section 1.xv Summary of Part 1 62

Answers to Part 1 self-assessment exercises 63

Part 2: Fluid and electrolyte homeostasis.

Normal physiology

Section 2.i Fluid translocation: plasma to ISF and ISF to ICF 83

Section 2.ii Renal function: a brief overview 88

Section 2.iii Renal regulation of blood composition 93

Section 2.iv Self-assessment exercise 2.1 100

Section 2.v Minerals: key roles in physiology and metabolism 102

Section 2.vi Sodium and potassium 106

Section 2.vii Sodium and water homeostasis: renal regulation of blood pressure and blood volume 109

Section 2.viii Calcium and magnesium 115

Section 2.ix Iron 123

Section 2.x Selected trace elements: Mn, Co, Se and S 128

Section 2.xi Anions: bicarbonate, chloride, phosphate and proteins 130

Section 2.xii Self-assessment exercise 2.2 132

Section 2.xiii Laboratory measurements 1: Osmometry 134

Section 2.xiv Laboratory measurements 2: Ion selective electrodes (ISEs) 138

Section 2.xv Laboratory measurements 3: Calcium, magnesium, vitamin D, phosphate and iron 147

Section 2.xvi Laboratory measurements 4: Miscellaneous methods for clinically useful analytes 150

Section 2.xvii Self-assessment exercise 2.3 154

Disorders of fluid and electrolyte balance

Section 2.xviii Introduction 157

Section 2.xix Principles of data interpretation 160

Section 2.xx Sodium, protein and water 167

Section 2.xxi Hypernatraemia 173

Section 2.xxii Hyponatraemia 179

Section 2.xxiii Disturbances of potassium homeostasis 184

Section 2.xxiv Hyperkalaemia 186

Section 2.xxv Hypokalaemia 189

Section 2.xxvi Disturbances of calcium or magnesium balance 193

Section 2.xxvii Disorders of iron homeostasis 200

Section 2.xxviii Self-assessment exercise 2.4 202

Section 2.xxix Summary of Part 2 207

Answers to Part 2 self-assessment exercises 209

Part 3: Acid-base homeostasis.

Normal physiological processes

Section 3.i Acidity, pH and buffers: recap of some basic chemistry 221

Section 3.ii Some worked example calculations 224

Section 3.iii Self-assessment exercise 3.1 227

Section 3.iv Homeostasis and the 'daily acid challenge' 228

Section 3.v Physiological buffering 232

Section 3.vi The role of the kidney in acid-base homeostasis 237

Section 3.vii Respiration: gas pressures and breathing 244

Section 3.viii The role of red cells: gas carriage by haemoglobin 248

Section 3.ix Self-assessment exercise 3.2 253

Section 3.x The liver and gastrointestinal tract in acid-base homeostasis 254

Section 3.xi The 'traditional' versus the 'modern' view of acid-base homeostasis 257

Section 3.xii Stewart's three independent factors 262

Section 3.xiii Laboratory measurement of pH, PCO2 and bicarbonate 268

Acid-base disturbances

Section 3.xiv Classification of primary changes based on pH and aetiology 273

Section 3.xv Overview of mechanisms 276

Section 3.xvi Physiological correction of primary disturbances 279

Section 3.xvii Check the data 283

Section 3.xviii Self-assessment exercise 3.3 284

Section 3.xix Non-respiratory (metabolic) acidosis 287

Section 3.xx Metabolic acidosis: detailed case studies 293

Section 3.xxi Non-respiratory (metabolic) alkalosis: overview 297

Section 3.xxii Non-respiratory (metabolic) alkalosis: causes 299

Section 3.xxiii Self-assessment exercise 3.4 302

Section 3.xxiv Respiratory disorders: overview 303

Section 3.xxv Physiological consequences of respiratory disorders 305

Section 3.xxvi Respiratory disorders: case studies 307

Section 3.xxvii Summary of Part 3 312

Answers to Part 3 self-assessment exercises 314

Appendix 325

Index 329