For Churchill Livingstone: Publisher: Timothy Home Project Editor: Janice Urquhart Indexer: Helen McKillop Project Controller: Nancy Arnott Design Direction: Jim Farley ILLUSTRATED PHYSIOLOGY B. R. Mackenna MB ChB PhD FRCP(Glasg) Formerly Senior Lecturer, Institute of Physiology, University of Glasgow, Glasgow, UK R. Callander FFPh FMAA AIMBI Formerly Director of Medical Illustration, University of Glasgow, Glasgow, UK SIXTH EDITION Δ CHURCHILL LIVINGSTONE EDINBURGH LONDON NEW YORK OXFORD PHILADELPHIA ST LOUIS SYDNEY TORONTO 1997 CHURCHILL LIVINGSTONE An imprint of Elsevier Limited © Elsevier Limited 1990. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without either the prior permission of the publishers or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London WIT 4LP. Permissions may be sought directly from Elsevier 's Health Sciences Rights Department in Philadelphia, USA: phone: (+1) 215 238 7869, fax: (+1) 215 238 2239, e-mail: [email protected]. You may also complete your request on-line via the Elsevier Science homepage (http://www.elsevier.com), by selecting 'Customer Support7 and then Obtaining Permissions'. First edition 1963 Spanish translation 1981 Italian translation 1966 Fourth edition 1983 Second edition 1970 Reprinted 1984,1986 Danish translation 1973 Fifth edition 1990 Third edition 1975 Reprinted 1991,1992,1995 Japanese translation 1976 Sixth edition 1997 ISBN 0 443 05060 0 Reprinted 1998, 2001, 2003,2004 International Student Edition ISBN 0 443 05779 6 Reprinted 1997,1998 (twice), 2001, 2004 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress. Medical knowledge is constantly changing. As new information becomes available, changes in treatment, procedures, equipment and the use of drugs become necessary. The author and the publishers have, as far as it is possible, taken care to ensure that the information given in this text is accurate and up to date. However, readers are strongly advised to confirm that the information, especially with regard to drug usage, complies with current legislation and standards of practice. your source for books, journals and multimedia in the health sciences www.elsevierhealth.com The publisher's policy is to use paper manufactured from sustainable forests Printed in China C/05/06 PREFACE TO THE SIXTH EDITION We continue to be encouraged by the number of students who find Illustrated Physiology useful. As the demands on students' time continue to increase, the use of a book with minimal text seems to be popular with many of them. All the material has again been updated for this edition. For students lacking knowledge of chemistry or physics we have added pages on atomic and molecular structure with a special mention for DNA and RNA since it is clear that an understanding of genes and their role in body function is increasingly essential for all those who take an interest in advancements in medicine. New material has been added about immunity, the alimentary system, the cardiovascular system, the autonomie nervous system and especially the renal system all of which are particularly important to medical students and health-care professionals. Difficult concepts such as the function of the loop of Henle, visual and muscle receptors and plasma clearance have been given additional coverage. We are indebted to the following colleagues and friends in the Institute of Physiology for helpful discussion and suggestions: Ms Géorgie Docherty, Dr H. Y. Elder, Dr M. Gladden, Dr D. J. Miller and Dr J. D. Morrison. We should like to express our gratitude to our Project Editor, Janice Urquhart of Churchill Livingstone, Edinburgh for the efficient way she has guided the production of this edition of our book. We hope that Illustrated Physiology will continue to be useful to nurses and other health-care workers and that many medical and dental students both undergraduate and postgraduate will find it a valuable aid to learning and revision. 1997 B. R. Mackenna R. Callander PREFACE TO THE FIRST EDITION This book grew originally from the need to provide visual aids for the large number of students in this department who come to the study of human physiology with no background of mammalian anatomy and often without any conventional training in either the biological or the physical and chemical sciences. Such students include postgraduates studying for the Diploma or Degree in Education, undergraduates working for Degrees in Science, laboratory technicians taking courses for the Ordinary and High National Certificates in Biology, and the increasing number of medical auxiliaries (physiotherapists, occupational therapists, radiographers, cardiographers, dieticians, almoners and social workers) many of whom are required to study to quite advanced levels at least regional parts of the subject. Many medical, dental and pharmacy students, as well as nurses in training, have been good enough to indicate that they too find diagrams which summarize the salient points of each topic valuable aids to learning or revision. It is our hope that some of these groups may find our book helpful. Each page is complete in itself and has been designed to oppose its neighbour. It is hoped that this will facilitate the choice of those pages thought suitable for any one course while making it easy to omit those which are too detailed for immediate consideration. A book of this sort is largely derivative and it is impossible to acknowledge our wider debt. We wish to record our gratitude, however, to Professor R. C. Garry for his generous permission to borrow freely from the large collection of teaching diagrams built up over the years by himself and his staff; to Dr H. S. D. Garven and Dr G. Leaf for permission to use some of their own teaching material; and to Messrs Ciba Pharmaceutical Products Inc. from whose fine book of Medical Illustrations by Dr Frank H. Netter the diagram of the Cranial Nerves has been modified. We are indebted to the following colleagues and friends who read parts of the original draft and offered helpful criticism: Dr H. S. D. Garven, Dr J. S. Gillespie, Mr J. A. Gilmour, Dr M. Holmes, Dr B. R. Mackenna, Mr T. McClurg Anderson, Dr I. A. Boyd, Dr R. Y. Thomson, Dr J. B. deV. Weir. We should like to express our gratitude to Mr Charles Macmillan and Mr James Parker of Messrs E. & S. Livingstone Ltd. for their unfailing courtesy and encouragement, and to Mrs Elizabeth Callander for help in preparing the index. Ann B. McNaught Robin Callander 1963 WHAT IS PHYSIOLOGY? Physiology is the study of the function of living matter. Hence, there are many types of Physiology including Bacterial Physiology, Plant Physiology and Human Physiology. To understand how human beings function it is necessary to appreciate that all living things are made of microscopic units of protoplasm called cells. There are some very simple living creatures which consist of just one cell, for example the amoeba which lives in pond water. These unicellular creatures demonstrate the structure of all animal cells and show the phenomena which distinguish living from non-living things. Hence we start with a brief look at such creatures. The human being is made up of 75 trillion cells which are arranged in a variety of combinations and form various degrees of organized structure. Collections of cells with similar properties form tissues (e.g. muscular tissue, nervous tissue). Different tissues combine to form organs (e.g. kidneys, brain, heart). Organs are linked together to form organ systems (e.g. the heart and blood vessels form the cardiovascular system). 56% of the adult human body is fluid. Most is inside the cells (intracellular fluid). However about one third is outside the cells (extracellular fluid) and consists of the plasma of the blood which circulates in the cardiovascular system, plus the fluid which surrounds the cells (intercellular or interstitial fluid). Cells receive their nutrients from the interstitial fluid and as the nutrients are used up more must be brought to this surrounding fluid. Likewise the cells pass waste products to their bathing fluid and this waste must not be allowed to accumulate or it will poison the cells. In addition, the concentration of salts in the interstitial fluid must be kept constant for the cells to function normally. The extracellular fluid was given the special name the internal environment of the body or the milieu intérieur in the 19th century by the French physiologist Claude Bernard. Physiologists use the term homeostasis to mean maintenance of constant conditions in the internal environment. Thus the main function of most of the tissues and organ systems of the human body is to maintain the constancy of the internal environment so that its cells can function normally. However, to do so the systems must be controlled and regulated. The nervous and hormonal systems are specialized for this regulatory function. How cells function, how the tissues and organ systems maintain homeostasis and how the systems are regulated is basically what human physiology is about and that is what is illustrated in the following pages. CHAPTER 1 INTRODUCTION: ATOMS, ELEMENTS, CELLS, TISSUES AND SYSTEMS Elements, Atoms and Isotopes 2 Electrons, Atomic Numbers and Weights; Mass Numbers 3 Bonds between Atoms 4 Basic Constituents of Protoplasm 5 The Amoeba 6 The Phenomena which characterize all living things are shown by the amoeba 7 The Paramecium 8 The Cell 9 Fine Structure of Cells 10 Organelles 11, 12 Cell Division (Mitosis) 13 Differentiation of Animal Cells 14 Organization of Tissues 15 Epithelia 16 Connective Tissues (CT) 17-19 Muscular Tissues 20 Nervous Tissues 21-23 Junctions between Cells 24 Cell Division (Meiosis) 25 Development of the Individual 26 The Body Systems 27 INTRODUCTION: ATOMS. ELEMENTS, CELLS, TISSUES AND SYSTEMS ELEMENTS, ATOMS AND ISOTOPES The chemical ELEMENT cannot be broken into simpler materials by chemical means. If two or more elements are combined they form a COMPOUND. The letter abbreviations by which elements are labelled are called CHEMICAL SYMBOLS and are derived from the first or first and second letters of the English or Latin names of the element. The commonest elements found in the body are C (carbon), H (hydrogen), N (nitrogen) and O (oxygen). See page 5. Each element is made up of ATOMS which are composed of even smaller particles. ^ ELECTRON LEVELS ^ or ^ ELECTRON SHELLS ^_ PROTON (p+) > NUCLEUS "■"-"— NEUTRON (n°) ELECTRON (el Positively charged PROTONS and uncharged NEUTRONS are located in the NUCLEUS. Negatively charged ELECTRONS are in constant motion round the nucleus in energy levels or electron shells (page 3). The numbers of + ve protons and -ve electrons are equal, hence atoms are electrically neutral. The unit of mass for atoms and their particles is the DALTON. A neutron has a mass of 1.008 daltons; a proton 1.007 daltons; an electron 0.0005 daltons, hence practically all the mass of an atom is in the nucleus. The difference between one element and another is due to the difference in the number of PROTONS in their atoms. However, some atoms of the SAME element have different numbers of NEUTRONS. Those different atoms are called ISOTOPES of the element. All isotopes have the same chemical properties because the chemical properties of an element are determined by their ELECTRONS and all atoms of an element have the same number of electrons. Certain isotopes, called RADIOACTIVE ISOTOPES, are unstable and emit various kinds of radiation viz. ALPHA (a) particles composed of two protons and two neutrons; BETA (ß) particles composed of particles like electrons but can be either positively or negatively 2 charged; GAMMA (γ) radiation, electromagnetic waves similar to very strong X-rays. INTRODUCTION: ATOMS, ELEMENTS. CELLS. TISSUES AND SYSTEMS ELECTRONS; ATOMIC NUMBERS AND WEIGHTS; MASS NUMBERS ELECTRONS possess different amounts of energy and are located in numbered ENERGY LEVELS. The lowest energy level (n = 1) can contain a maximum of 2 electrons. The second energy level (n = 2) can con- tain 8 electrons, the third (n =3) up to 18 electrons, and so on up to n = 7. Electron levels are sometimes called SHELLS and are labelled K,L,M,N, etc. M N To achieve stability, atoms either empty their outermost energy levels or fill it up to the maximum. In so doing they may give up, accept or share electrons with other atoms, whichever is easiest. The VALENCE (com- bining capacity) is the number of extra or deficient electrons inthe valence electron energy level (outermost). ATOMIC STRUCTURE OF COMMON ELEMENTS Atomic number = number of protons. Mass number = number of protons + neutrons (mass numbers of only the commonest isotopes are given). Atomic weight = total mass of protons + neutrons + electrons. . n=1 n=2 (H) Hydrogen (C) Carbon (N) Nitrogen Atomic number 1 Atomic number 6 Atomic number 7 Mass number 1 Mass number 12 Mass number 14 Atomic weight 1.008 Atomic weight 12.011 Atomic weight 14.007 Valence n=3 n=4 v energy level (O) Oxygen (Na) Sodium (CD Chlorine Atomic number 8 Atomic number 11 Atomic number 17 (K)Potassium Mass number 16 Mass number 23 Mass number 35 Atomic number 19 Atomic weight 15.999 Atomic weight 29.99 Atomic weight 35.453 Mass number 39 Atomic weight 39.098 The valence electron energy levels of both sodium (n = 3) and potassium (n = 4) have only one electron. It is easier to get rid of one electron than to fill these outermost levels with electrons. The valence level of chlorine (n = 3) is one short of stability, hence Na and K tend to combine with Cl in chemical reactions. When atoms combine in this way they form MOLECULES. 3 INTRODUCTION: ATOMS. ELEMENTS. CELLS, TISSUES AND SYSTEMS BONDS BETWEEN ATOMS The outer electrons of one atom may interact with the outer electrons of other atoms, producing attractive forces or CHEMICAL BONDS: IONIC, COVALENT or HYDROGEN. In IONIC BONDS, electrons are actually transferred from one atom to another. Such atoms or aggregates of atoms are then called IONS. The atom gaining an electron or electrons becomes negatively charged, called an ANION (more -ve electrons than + ve protons). The atom which loses electrons becomes positively charged, called a CATION (more + ve protons than -ve electrons). Since oppositely charged particles attract one another, oppositely charged ions can be held together by this attraction to form electrically neutral ionic compounds. Such attractions are called ionic attractions or IONIC BONDS. Sodium ion (Na+) Chlorine ion (CI ) Sodium atom (Na) Chlorine atom (CI) Sodium chloride molecule (NaCI) In COVALENT BONDS, atoms SHARE electrons in their outer energy level. This is very common. In an H molecule the two atoms share 2 one pair of electrons which are most often in the region between the two nuclei. The attraction between the ELECTRONS in the middle and the PROTONS in the two Hydrogen atoms Hydrogen molecule nuclei holds the molecule strongly together. If one pair of electrons are shared (e.g. H ) a SINGLE covalent bond is formed. Two pairs 2 shared (e.g. 0 ) form a DOUBLE bond. Three pairs (e.g. N ) a TRIPLE bond. 2 2 Shared electrons, attracted equally to both atoms, as with H , form 2 a NON-POLAR COVALENT BOND. However, if one atom attracts the H 0 2 shared electrons more strongly than the other, the bond is a POLAR COVALENT BOND and produces POLAR MOLECULES with positive and negative areas. Water is a polar molecule. Oxygen attracts the shared electrons more strongly and becomes somewhat negative. The hydrogen portions become somewhat positive. Polar bonds allow water to dissolve many molecules that are important to life. HYDROGEN BONDS Oppositely charged regions of polar molecules can attract one another. Such a bond between hydrogen and e.g. oxygen or nitrogen is called lH+WHl HVCH1 a HYDROGEN BOND. These occur in water, proteins and other large molecules but are weak bonds (5% as IH+ H" strong as covalent bonds). However, large molecules may contain many H-bonds e.g. between bases in DNA <ϋ£& and can thus give strength and three-dimensional VH+ H+J 4 shape to e.g proteins and nucleic acids.