Principles of Renal Physiology

211 Pages·2000·14.938 MB·English

by  Chris Lote (auth.)

Principles of Renal Physiology
4th Edition
Principles of
Renal Physiology
4th Edition
Chris Lote
Professor of Experimental Nephrology,
University of Birmingham, UK
SPRINGER SCIENCE+BUSINESS MEDIA, B.V.
A c.I.P. Catalogue record for this book is available from the Library of Congress
ISBN 978-0-7923-6178-7 ISBN 978-94-011-4086-7 (eBook)
DOI 10. 1007/978-94-011-4086-7
Prin led on acid-free paper
AII Rights Reserved
Fourth Edition © 2000 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 2000
No part of the material protected by this copyright notice may be reproduced in any form or by
any means, electronic or mechanical, including photocopying, record ing or by any other informa
tion storage and retrieval system, without written permission from the copyright owner.
Contents
Preface ix
Terminology and abbreviations x
1 The body fluids 1
1.1 Introduction 1
1.2 Body water 2
1.3 Body fluid osmolality 2
1.4 Distribution of ions across biological membranes 6
1.5 Fluid exchanges between body compartments 8
1.6 Fluid exchanges between the body and the external
environment 11
1.7 Ionic composition of the body fluids 12
1.8 Ion exchanges between the body and the external
environment 13
1.9 Body fluid compartments: methods of measurement 14
Further reading 19
Problems 19
2 Essential anatomy of the kidney 20
2.1 Introduction 20
2.2 General morphology and cellular organization 20
2.3 Blood supply and vascular structure within the kidney 27
2.4 Renal lymphatic drainage 29
2.5 Juxtaglomerular apparatus 29
Further reading 33
3 Glomerular filtration 34
3.1 The filter 34
3.2 Glomerular filtration process 37
3.3 Composition of the glomerular filtrate 43
3.4 Filtration fraction 44
3.5 Tubulo-glomerular feedback 44
Further reading 45
Problems 46
v
vi Contents
4 Tubular transport 47
4.1 Introduction 47
4.2 Primary and secondary active transport 47
4.3 Ion channels, uniporters and facilitated diffusion 50
4.4 Para cellular movement 51
4.5 Water absorption 51
4.6 Fractional excretion and fractional reabsorption 52
Further reading 52
5 The proximal tubule 53
5.1 Morphology of proximal tubule cells 53
5.2 Proximal tubular handling of sodium 53
5.3 Uptake of NaCl and water into peritubular capillaries 57
5.4 Relationship of proximal tubular reabsorption to
glomerular filtration rate 58
5.5 Proximal tubular reabsorption of other solutes 58
5.6 Secretory processes in the proximal tubule 66
Further reading 68
Problem 69
6 The loop of Henle, distal tubule and collecting duct 70
6.1 The loop of Henle 70
6.2 Collecting tubules 76
6.3 Importance of urea in countercurrent multiplication 76
6.4 Further requirements of the countercurrent multiplication
mechanism: the vasa recta 78
6.5 Long and short loops of Henle 79
6.6 Regulation of urine concentration 80
6.7 Other hormones affecting distal nephron transport processes 84
Further reading 84
7 Renal blood flow and glomerular filtration rate 86
7.1 Measurement of renal blood flow and
glomerular filtration rate 86
7.2 Regulation of renal blood flow and glomerular filtration rate 92
Further reading 94
Problem 95
8 Regulation of body fluid osmolality 96
8.1 Introduction 96
8.2 Osmoreceptors 97
8.3 Regulation of water excretion and water reabsorption 102
Further reading 107
Contents vii
9 Regulation of body fluid volume 108
9.1 Introduction 108
9.2 Aldosterone 109
9.3 Renin and angiotensin, and their relationship to aldosterone 111
9.4 Starling forces and proximal tubular sodium reabsorption 114
9.5 Renal nerves 116
9.6 Prostaglandins and other arachidonate metabolites 116
9.7 Atrial natriuretic peptide and urodilatin 117
9.8 Other factors which may be involved in
regulating sodium excretion 118
9.9 ADH and the relationship between osmotic
regulation and volume regulation 120
9.10 Overall scheme of body fluid volume regulation 121
Further reading 122
10 Renal regulation of body fluid pH 124
10.1 Introduction 124
10.2 Physiological buffers 124
10.3 Renal regulation of plasma bicarbonate concentration 127
10.4 Regulation of H+ secretion according to
acid-base balance requirements 134
Further reading 142
Problem 142
11 Renal control of body fluid potassium content 143
11.1 Importance of K+ in the body 143
11.2 Regulation of body K+ 144
11.3 Hypokalaemia 146
11.4 Hyperkalaemia 148
Further reading 149
12 Renal regulation of body calcium, magnesium and phosphate 150
12.1 Introduction 150
12.2 Calcium 150
12.3 Phosphate 153
12.4 Calcium and phosphate homeostasis 154
12.5 Magnesium 157
Further reading 160
13 Summary of the principal reabsorptive and secretory processes
in the nephron segments 161
13.1 Introduction 161
13.2 Sodium 161
viii Contents
13.3 Water 161
13.4 Potassium 163
13.5 Hydrogen ions and HC03" 163
13.6 Phosphate 164
13.7 Calcium 164
13.8 Glucose 164
13.9 Urea and other nitrogenous waste products 164
14 Disease conditions which alter renal sodium
and water reabsorption 166
14.1 Introduction 166
14.2 Oedema 166
14.3 Congestive heart failure 168
14.4 Hypovolaemia and shock 170
14.5 Hypertension 176
14.6 Liver disease 179
14.7 Nephrotic syndrome 181
Further reading 182
15 Use of diuretics 183
15.1 Introduction 183
15.2 Osmotic diuretics 183
15.3 Loop diuretics 184
15.4 Thiazides 185
15.5 Aldosterone antagonists 185
15.6 N a channel blockers 186
15.7 Carbonic anhydrase inhibitors 186
15.8 Clinical use of diuretics 186
Further reading 188
Answers to problems 189
Index 193
Preface to the fourth edition
The first edition of this book appeared in 1982. In the preface to that first edi
tion, I wrote 'This book is based on the lecture course in renal physiology
which I give to medical students at the University of Birmingham. The pur
pose of the book is primarily to set out the principles of renal physiology for
preclinical medical students, and it is therefore concerned mainly with normal
renal function. However, diseases or abnormalities in other body systems may
lead to adaptations or modifications of renal function, so that a good knowl
edge of renal physiology is essential to the understanding of many disease
states, for example the oedema of heart failure or liver disease, or the conse
quences of haemorrhage and shock.' The new edition is still based on the lec
tures which I continue to give at Birmingham University, but over the years
the course has gradually changed, to being a system based course covering all
aspects of the kidney - the anatomy, physiology, pharmacology and pathology.
The new edition of the book, which has been extensively revised and rewritten,
reflects this. However, it continues to offer a concise, easily readable format,
primarily intended for undergraduate medical and medical science students.
This new edition will carry the book through to twenty years of continuous
publication, so it must be doing something right! I hope the new generation of
readers will find it interesting and that it meets their needs, and I would like to
encourage all of them to let me have their comments and suggestions.
Chris Lote
ix
Terminology and
abbreviations
General
ADH Antidiuretic hormone (vasopressin)
ANP Atrial natriuretic peptide
EeG Electrocardiogram
ERPF Effective renal plasma flow
GFR Glomerular filtration rate
RBF Renal Blood flow
RPF Renal plasma flow
Units of measurement
mosmol milliosmoles
mmHg millimetres of mercury (pressure measurement)
mM millimoles I litre
mmol millimoles
nm nanometres (10-9 metres)
fLm micrometres (10-6 metres)
Symbols
Square brackets, [], denote concentration, e.g. plasma [Na +] = 140 mM means
plasma sodium concentration = 140 mM.
x
1
The body fluids
1.1 Introduction
The body fluids can be considered to be distributed between two compart
ments, intracellular and extracellular. The extracellular compartment can in
turn be divided into a number of sub-compartments. These are: (a) the plasma
(extracellular fluid within the vascular system); (b) the interstitial fluid (extra
cellular fluid outside the vascular system, and functionally separated from it
by the capillary endothelium); and (c) transcellular fluids. Transcellular fluid
can be defined as extracellular fluid which is separated from the plasma by an
additional epithelial layer, as well as by the capillary endothelium. Transcellular
fluids have specialized functions and include the fluid within the digestive
and urinary tracts, the synovial fluid in the joints, the aqueous and vitreous
humours in the eye and the cerebrospinal fluid.
The environment in which our cells exist is not the environment of the out
side of the body. The immediate environment of the cells is the extracellular
fluid. This internal environment (a term first used by the nineteenth century
French physiologist, Claude Bernard) provides the stable medium necessary
for the normal functioning of the cells of the body. The internal environment
maintains the correct concentrations of oxygen, carbon dioxide, ions and nutri
tional materials, for the normal functioning of the cells.
Maintenance of the constancy of the internal environment (which the
American physiologist, Walter B. Cannon, called 'homeostasis') is ensured by
several body systems. For example, the partial pressures of oxygen and carbon
dioxide are regulated by the lungs. The kidneys playa vital role in homeosta
sis. In fact, they can reasonably be regarded as the most important regulatory
organs for controlling the internal environment, since they control not only
the concentration of waste products of metabolism, but also the osmolality,
volume, acid-base status and ionic composition of the extracellular fluid and,
indirectly, regulate these same variables within the cells.
Much of this book is devoted to an examination of the ways in which the
kidneys perform these regulatory functions. First, however, it is necessary to
examine the normal composition of the body fluids.
1
C. Lote, Principles of Renal Physiology
© Springer Science+Business Media Dordrecht 2000