Boston Burr Ridge, IL Dubuque, IA Madison, WI New York San Francisco St. LouisBangkok Bogotá Caracas Kuala Lumpur Lisbon London Madrid Mexico CityMilan Montreal New Delhi Santiago Seoul Singapore Sydney Taipei Toronto

Third Edit ion

Kenneth S. SaladinGeorgia College and State University

with Leslie Miller, M.S.N.Clinical Consultant

Iowa State University

The Unity of Form and Function

ANATOMY & PHYSIOLOGY: THE UNITY OF FORM AND FUNCTIONTHIRD EDITION

Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright © 2004, 2001, 1998 by The McGraw-Hill Companies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning.

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Publisher: Martin J. LangeSponsoring editor: Michelle WatnickMarketing manager: James F. ConnelyDirector of development: Kristine TibbettsSenior project manager: Mary E. PowersSenior production supervisor: Laura FullerLead media project manager: Audrey A. ReiterSenior media technology producer: Barbara R. BlockDesigner: K. Wayne HarmsCover/interior designer: Nathan BahlsCover photograph: EyeWire Collection/GettyimagesCover illustration: Imagineering STA Media Services, Inc.Senior photo research coordinator: John C. LelandPhoto research: Mary ReegSupplement producer: Brenda A. ErnzenFreelance developmental editor: Terri SchieslCompositor: Carlisle Communications, Ltd.Typeface: 10/12 MeliorPrinter: Von Hoffmann Press, Inc.

The credits section for this book begins on page C-1 and is considered an extension of the copyright page.

Library of Congress Cataloging-in-Publication Data

Saladin, Kenneth S.Anatomy & physiology : the unity of form and function/Kenneth S.

Saladin with Donna Van Wynsberghe.—3rd ed.p. cm.

Includes index.ISBN 0-07-242903-8 (hbk. : alk. paper)1. Human physiology. 2. Human anatomy. I. Title: Anatomy and

physiology. II. Van Wynsberghe, Donna. III. Title.

QP34.5 .S23 2004612—dc21 2002011274

CIP

www.mhhe.com

McGraw-Hill Higher EducationA Division of The McGraw-Hill Companies

Ken Saladin has taught since 1977 at Georgia College andState University, a public liberal arts university inMilledgeville, Georgia. He earned his B.S. in zoology atMichigan State University and Ph.D. in parasitology atFlorida State University. In addition to human anatomy andphysiology, he teaches histology, neuroanatomy, biomed-ical etymology, animal behavior, sociobiology, and otherbiological and interdisciplinary courses. Ken is a six-timerecipient of the Honor Professor award from Phi Kappa Phifor outstanding mentoring of his undergraduate students.He received the university’s 1998 Excellence in Researchand Publication Award for the first edition of this book, andpartly in recognition of its growing success, he was namedDistinguished Professor in 2001. Ken is an active memberof the Human Anatomy and Physiology Society and theSociety for Integrative and Comparative Biology. He servedas a developmental reviewer and wrote instructor’s supple-ments for several other McGraw-Hill anatomy and physiol-ogy textbooks for a number of years before beginning thisbook. Ken is married to Diane Saladin, a registered nurse.They regard their major joint achievement as having main-tained their faculties moderately intact while raising twochildren through adolescence.

About the Author

iii

I dedicate this edition of Anatomy &Physiology to my daughter

Nicole

becoming a marine biologist at the Universityof Miami and making her dad proud.

Ken and his daughter, Nicole, on Isla San Cristóbal, theGalápagos Islands, June 2002

Part OneOrganization of the Body1 Major Themes of Anatomy and Physiology 1

Atlas A General Orientation to Human Anatomy 29

2 The Chemistry of Life 55

3 Cellular Form and Function 93

4 Genetics and Cellular Function 129

5 Histology 157

Part TwoSupport and Movement6 The Integumentary System 191

7 Bone Tissue 217

8 The Skeletal System 243

9 Joints 293

10 The Muscular System 325

Atlas B Surface Anatomy 39111 Muscular Tissue 407

Part ThreeIntegration and Control12 Nervous Tissue 443

13 The Spinal Cord, Spinal Nerves, and Somatic Reflexes481

14 The Brain and Cranial Nerves 515

15 The Autonomic Nervous System and Visceral Reflexes563

16 Sense Organs 585

17 The Endocrine System 635

Part FourRegulation and Maintenance18 The Circulatory System: Blood 679

19 The Circulatory System: The Heart 715

20 The Circulatory System: Blood Vessels and Circulation747

21 The Lymphatic and Immune Systems 799

22 The Respiratory System 841

23 The Urinary System 879

24 Water, Electrolyte, and Acid-Base Balance 915

25 The Digestive System 939

26 Nutrition and Metabolism 985

Part FiveReproduction and Development27 The Male Reproductive System 1017

28 The Female Reproductive System 1049

29 Human Development 1089

Appendix A Periodic Table of the Elements A–1Appendix B Answers to Chapter Review Questions A–2Appendix C Lexicon of Biomedical Word Elements A–6Glossary G–1Credits C–1Index I–1

Brief Contents

iv

Contents

Preface viii

Part OneOrganization of the Body

Chapter 1Major Themes of Anatomy and Physiology 1The Scope of Anatomy and Physiology 2The Origins of Biomedical Science 3Scientific Method 7Human Origins and Adaptations 9Human Structure 12Human Function 14The Language of Medicine 19Review of Major Themes 21Chapter Review 25

Atlas AGeneral Orientation to Human Anatomy 29Anatomical Position 30Anatomical Planes 31Directional Terms 31Surface Anatomy 32Body Cavities and Membranes 36Organ Systems 38A Visual Survey of the Body 39Chapter Review 52

Chapter 2The Chemistry of Life 55Atoms, Ions, and Molecules 56Water and Mixtures 63Energy and Chemical Reactions 68Organic Compounds 71Chapter Review 88

Chapter 3Cellular Form and Function 93Concepts of Cellular Structure 94The Cell Surface 98Membrane Transport 106The Cytoplasm 115Chapter Review 125

Chapter 4Genetics and Cellular Function 129The Nucleic Acids 130Protein Synthesis and Secretion 134DNA Replication and the Cell Cycle 139Chromosomes and Heredity 145Chapter Review 152

Chapter 5Histology 157The Study of Tissues 158Epithelial Tissue 160Connective Tissue 166Nervous and Muscular Tissue—

Excitable Tissues 175Intercellular Junctions, Glands,

and Membranes 178

Tissue Growth, Development, Death, and Repair 183

Chapter Review 187

Part TwoSupport and Movement

Chapter 6The Integumentary System 191Structure of the Skin and Subcutaneous

Tissue 192Functions of the Skin 198Hair and Nails 200Hair Growth and Loss 203Cutaneous Glands 205Diseases of the Skin 208Connective Issues 212Chapter Review 213

Chapter 7Bone Tissue 217Tissues and Organs of the Skeletal

System 218Histology of Osseous Tissue 221Bone Development 225Physiology of Osseous Tissue 229Bone Disorders 234Chapter Review 240

Chapter 8The Skeletal System 243Overview of the Skeleton 244The Skull 246The Vertebral Column and Thoracic Cage 262The Pectoral Girdle and Upper Limb 270The Pelvic Girdle and Lower Limb 277Connective Issues 288Chapter Review 289

v

Chapter 9Joints 293Joints and Their Classification 294Fibrous, Cartilaginous, and Bony Joints 295Synovial Joints 298Anatomy of Selected Diarthroses 310Chapter Review 322

Chapter 10The Muscular System 325The Structural and Functional

Organization of Muscles 326Muscles of the Head and Neck 330Muscles of the Trunk 345Muscles Acting on the Shoulder and

Upper Limb 352Muscles Acting on the Hip and Lower Limb 369Connective Issues 387Chapter Review 388

Atlas BSurface Anatomy 391The Importance of External Anatomy 392Head and Neck 393Trunk 394Upper Limb 398Lower Limb 400Muscle Test 406

Chapter 11Muscular Tissue 407Types and Characteristics of Muscular

Tissue 408Microscopic Anatomy of Skeletal Muscle 409The Nerve-Muscle Relationship 412Behavior of Skeletal Muscle Fibers 416Behavior of Whole Muscles 423Muscle Metabolism 427Cardiac and Smooth Muscle 432Chapter Review 438

Part ThreeIntegration and Control

Chapter 12Nervous Tissue 443Overview of the Nervous System 444Nerve Cells (Neurons) 445

Supportive Cells (Neuroglia) 449Electrophysiology of Neurons 455Synapses 463Neural Integration 468Chapter Review 476

Chapter 13The Spinal Cord, Spinal Nerves, and Somatic Reflexes 481The Spinal Cord 482The Spinal Nerves 490Somatic Reflexes 503Chapter Review 510

Chapter 14The Brain and Cranial Nerves 515Overview of the Brain 516Meninges, Ventricles, Cerebrospinal

Fluid, and Blood Supply 519The Hindbrain and Midbrain 524The Forebrain 529Higher Brain Functions 536The Cranial Nerves 546Chapter Review 558

Chapter 15The Autonomic Nervous System and Visceral Reflexes 563General Properties of the Autonomic

Nervous System 564Anatomy of the Autonomic

Nervous System 567Autonomic Effects on Target Organs 574Central Control of Autonomic Function 578Connective Issues 581Chapter Review 582

Chapter 16Sense Organs 585Properties and Types of Sensory

Receptors 586The General Senses 588The Chemical Senses 592Hearing and Equilibrium 597Vision 610Chapter Review 629

Chapter 17The Endocrine System 635Overview of the Endocrine System 636

The Hypothalamus and Pituitary Gland 637

Other Endocrine Glands 646Hormones and Their Actions 652Stress and Adaptation 662Eicosanoids and Paracrine

Signaling 664Endocrine Disorders 666Connective Issues 673Chapter Review 674

Part FourMaintenance

Chapter 18The Circulatory System: Blood 679Functions and Properties of Blood 680Plasma 683Blood Cell Production 684Erythrocytes 689Blood Types 694Leukocytes 699Hemostasis—The Control of Bleeding 702Chapter Review 709

Chapter 19The Circulatory System: The Heart 715Gross Anatomy of the Heart 716Cardiac Muscle and the Cardiac

Conduction System 726Electrical and Contractile Activity of

the Heart 728Blood Flow, Heart Sounds, and the

Cardiac Cycle 733Cardiac Output 737Chapter Review 743

vi Contents

Chapter 20The Circulatory System: Blood Vessels and Circulation 747General Anatomy of the Blood Vessels 748Blood Pressure, Resistance, and Flow 753Capillary Exchange 761Venous Return and Circulatory Shock 763Special Circulatory Routes 766Anatomy of the Pulmonary Circuit 767Anatomy of the Systemic Arteries 767Anatomy of the Systemic Veins 781Connective Issues 794Chapter Review 795

Chapter 21The Lymphatic and Immune Systems 799The Lymphatic System 800Nonspecific Resistance 808General Aspects of Specific Immunity 815Cellular Immunity 818Humoral Immunity 822Immune System Disorders 827Connective Issues 834Chapter Review 835

Chapter 22The Respiratory System 841Anatomy of the Respiratory System 842Mechanics of Ventilation 850Neural Control of Ventilation 857Gas Exchange and Transport 859Blood Chemistry and the Respiratory

Rhythm 867Respiratory Disorders 868Connective Issues 873Chapter Review 874

Chapter 23The Urinary System 879Functions of the Urinary System 880Anatomy of the Kidney 881Urine Formation I: Glomerular

Filtration 886Urine Formation II: Tubular

Reabsorption and Secretion 891Urine Formation III: Water

Conservation 897

Urine and Renal Function Tests 899Urine Storage and Elimination 903Connective Issues 909Chapter Review 910

Chapter 24Water, Electrolyte, and Acid-Base Balance 915Water Balance 916Electrolyte Balance 921Acid-Base Balance 926Chapter Review 934

Chapter 25The Digestive System 939General Anatomy and Digestive

Processes 940The Mouth Through Esophagus 943The Stomach 949The Liver, Gallbladder, and Pancreas 958The Small Intestine 964Chemical Digestion and Absorption 968The Large Intestine 974Connective Issues 979Chapter Review 980

Chapter 26Nutrition and Metabolism 985Nutrition 986Carbohydrate Metabolism 996Lipid and Protein Metabolism 1004Metabolic States and Metabolic Rate 1007Body Heat and Thermoregulation 1009Chapter Review 1013

Part FiveReproduction andDevelopment

Chapter 27The Male Reproductive System 1017Sexual Reproduction 1018Sex Determination and Development 1019Male Reproductive Anatomy 1023

Puberty and Climacteric 1030Sperm and Semen 1032Male Sexual Response 1037Chapter Review 1043

Chapter 28The Female Reproductive System 1049Reproductive Anatomy 1050Puberty and Menopause 1058Oogenesis and the Sexual Cycle 1061Female Sexual Response 1068Pregnancy and Childbirth 1070Lactation 1076Connective Issues 1082Chapter Review 1083

Chapter 29Human Development 1089Fertilization and Preembryonic

Development 1090Embryonic and Fetal Development 1094The Neonate 1101Aging and Senescence 1107Chapter Review 1117

Appendix A Periodic Table of theElements A–1

Appendix B Answers to Chapter ReviewQuestions A–2

Appendix C Lexicon of Biomedical WordElements A–6

Glossary G–1Credits C–1Index I–1

Contents vii

viii

Thank you to the colleagues and students who havemade this textbook so successful and helped to ensureits staying power in a very competitive textbook niche.Several people have asked me, with this book doing sowell, why I don’t retire from the classroom. The answeris that not only do I find classroom teaching the most ful-filling aspect of my profession, but also that it is my stu-dents who teach me how to write. I work continually atfinding more and more effective ways of getting con-cepts across to them, at turning on the light of insight.The best ideas for communicating difficult physiologicalideas often come to mind during my face-to-face inter-actions with students, and many are the times that I havedashed back from the lecture room to the drawing pad orkeyboard to sketch concepts for new illustrations orwrite down new explanations. Grading exams andhomework assignments also continually gives me newimpressions of whether I have effectively taught an ideathrough my writing. Thus, my students are my unwittingwriting teachers. This pertains also to the students in my“extended classroom”—students worldwide who usethe book and write to ask my help in understanding dif-ficult concepts.

What are the improvements in this edition? I con-tinue to aim for ever-better clarity, brevity, currency, andaccuracy. Physiology, especially, is a complex subject toexplain to beginning students, and I am always workingin both the lecture room and textbook to find clearer waysto explain it. Physiology also is a fast-growing field, andit’s a challenge to keep a book up to date without it grow-ing longer and longer. After all, our lecture periods andsemesters aren’t getting any longer! So, while updatinginformation, I have looked for ways to make my discus-sions more concise in each edition. I also continue to cor-rect errors as students and content experts have sent mequeries, corrections, and suggestions. Accuracy is, ofcourse, an advantage of a seasoned textbook over a new-comer, and this book has gained a lot of seasoning and alittle spice from my extensive correspondence with stu-dents and colleagues.

This preface describes the book’s intended audience,how we determined what students and instructors want inthe ideal A&P textbook, what has changed in this editionto best meet your needs, how this book differs from others,and what supplements are available to round out the totalteaching package.

AudienceThis book is meant especially for students who plan topursue such careers as nursing, therapy, health education,medicine, and other health professions. It is designed fora two-semester combined anatomy and physiology courseand assumes that the reader has taken no prior collegechemistry or biology courses. I also bear in mind thatmany A&P students return to college after interruptions toraise families or pursue other careers. For returning stu-dents and those without college prerequisites, the earlychapters will serve as a refresher on the necessary pointsof chemistry and cell biology.

Many A&P students also are still developing theintellectual skills and study habits necessary for successin a health science curriculum. There are many, too, forwhom English was not their original language. Therefore,I endeavor to write in a style that is clear, concise, andenjoyable to read, and to enliven the facts of science withanalogies, clinical remarks, historical notes, biographicalvignettes, and other seasoning that will make the bookenjoyable to students and instructors alike. Each chapteris built around pedagogic strategies that will make the sub-ject attainable for a wide range of students and instill thestudy and thinking habits conducive to success in moreadvanced courses.

How We Evaluated Your NeedsThis book has evolved through extensive research on theneeds and likes of A&P students and instructors. In devel-oping its three editions so far, we have collected evalua-tive questionnaires from reviewers; commissioneddetailed reviews from instructors using this book andthose using competing books; held focus groups fromcoast to coast in the United States, in which instructorsand students studied the book in advance, then met withus to discuss it in depth for several hours, including howit compared to other leading A&P textbooks; and createdpanels of A&P instructors to thoroughly analyze the entirebook and its art program. These efforts have involvedmany hundreds of faculty and students and generatedthousands of pages of reviews, all of which I have readcarefully in developing my revision plans. In a less formal

Preface

way, the book has improved because of the many e-mails Ireceive from instructors and students worldwide who notonly tell me what they like about it, but also raise sugges-tions for correction or improvement. I’ve responded gen-erously to these e-mails because I learn a great deal look-ing up answers to readers’ questions, finding sources tosubstantiate the book’s content, and sometimes findingthat I need to update, clarify, or correct a point.

How We’ve Met Your NeedsOur research has consistently revealed that the three qual-ities instructors value most in a textbook are, in descend-ing order of importance, writing style, illustration quality,and teaching supplements. I have focused my attentionespecially on the first two of these and on pedagogic fea-tures, while McGraw-Hill Higher Education has continu-ally engaged other authors and software developers to pro-duce a more diverse package of superb supplements forstudents and instructors.

Writing StyleStudents benefit most from a book they enjoy reading, abook that goes beyond presenting information to also tellan interesting story and engage the reader with a some-what conversational tone. That was my guiding principlein finding the right voice for the first edition, and itremains so in this one. I try to steer a middle course,avoiding rigid formality on one hand or a chatty conde-scending tone on the other. I feel I have succeeded whenstudents describe the tone as friendly, engaging, collo-quial, almost as if the author is talking to them, but nottalking down to them.

In devising ways to make the writing more concisewithout losing the qualities that make it interesting andenjoyable, I have been guided by reviewers who identifiedareas in need of less detail and by students who cited cer-tain areas as especially engrossing and pleasurable to read.In this edition, I somewhat reduced the number of bold-faced terms and the amount of vocabulary, and fine-tunedsuch mechanics as sentence length, paragraph breaks, andtopic and transitional sentences for improved flow. Insuch difficult topics as action potentials, blood clotting,the countercurrent multiplier, or aerobic respiration, Ithink this book will compare favorably in a side-by-sidereading of competing textbooks.

IllustrationsWhen I was a child, it was the art and photography in biol-ogy books that most strongly inspired me to want to learnabout the subject. So it comes as no surprise that studentsand instructors rate the visual appeal of this book as sec-ond only to writing style in importance. I developed many

illustrative concepts not found in other books. Profes-sional medical illustrators and graphic artists have ren-dered these, as well as the classic themes of A&P, in a vividand captivating style that has contributed a lot to a stu-dent’s desire to learn.

As the book has evolved through these three edi-tions, I have used larger figures and brighter colors;adopted simpler, uncluttered labeling; and continued toincorporate innovative illustrative concepts. A good illus-tration conveys much more information than several timesas much space filled with verbiage, and I have cut downon the word count of the book to allow space for larger andmore informative graphics.

The illustration program is more than line art. I con-tinue to incorporate better histological photography andcadaver dissections, including many especially clear andskillful dissections commissioned specifically for this book.

Several of my students have modeled for photographsin this book. As much as possible with the volunteers whocame forth, I have represented an ethnic variety of subjects,getting away from the unfortunate stereotype in some othertextbooks in which the photo models are all white.

SupplementsThe third most highly rated quality is the package of learn-ing supplements for the student and teaching aids for theinstructor. Instructors have rated overhead transparenciesthe most important of all supplements, and we now includetransparencies of every item of line art in the book, andsome of the photographs and tables. Included are unlabeledduplicates of many anatomical figures, useful for testing orlabeling to fit one’s individual teaching approach. A full setof both labeled and unlabeled illustrations is also availablein the Instructor’s Presentation CD-ROM.

Students have expressed growing enthusiasm andappreciation for the Online Learning Center and theEssential Study Partner. We have continued to enrichthese media with an abundance of learning aids andresources. These and other student and instructor supple-ments are listed and described on page xiii.

What Sets This Book Apart?Those who have not used or reviewed previous editionswill want to know how this book differs from others.

OrganizationThe sequence of chapters and placement of some topics inthis book differ from others. While I felt it was risky todepart from tradition in my first edition, reviewer com-ments have overwhelmingly supported my intuition thatthese represent a more logical way of presenting the

Preface ix

x Preface

human A&P. Indeed, some have written that they arechanging their teaching approach because of this book.

Heredity

I treat the most basic concepts of heredity in chapter 4 ratherthan waiting, as most books do, until the last chapter. Stu-dents would be ill-prepared to understand color blindness,blood types, hemophilia, sex determination, and other topicsif they didn’t already know about such concepts as dominantand recessive alleles, sex chromosomes, and sex linkage.

Muscle Anatomy and Physiology

I treat gross anatomy of the muscular system (chapter 10)immediately after the skeletal system and joints in order totie it closely to the structures on which the muscles actand to relate muscle actions to the terminology of jointmovements. This is followed by muscle physiology andthen neurophysiology so that these two topics can beclosely integrated in their discussions of synapses, neuro-transmitters, and membrane potentials.

Nervous System Chapters

Many instructors cite the nervous system as the most dif-ficult one for students to understand, and in manycourses, it is presented in a hurry before the clock runs outon the first semester. Other A&P textbooks devote sixchapters or more to this system. It is overwhelming to boththe instructor and student to cover this much material atthe end of the course. I present this system in five chap-ters, and notwithstanding my assignment of a separatechapter to the autonomic nervous system in this edition,this is still the most concise treatment of this systemamong the similar two-semester textbooks.

Urinary System

Most textbooks place the urinary system near the endbecause of its anatomical association with the reproductivesystem. I feel that its intimate physiological ties with thecirculatory and respiratory systems are much more impor-tant than this anatomical issue. The respiratory and uri-nary systems collaborate to regulate the pH of the body flu-ids; the kidneys have more impact than any other organ onblood volume and pressure; and the principles of capillaryfluid exchange should be fresh in the mind of a studentstudying glomerular filtration and tubular reabsorption.Except for an unavoidable detour to discuss the lymphaticand immune systems, I treat the respiratory and urinarysystems as soon as possible after the circulatory system.

“Insight” SidebarsEach chapter has from two to six special topic sidebarscalled Insights, listed by title and page number on the

opening page of each chapter. These fall into three cate-gories: 101 clinical applications, 13 on medical history,and 9 on evolutionary medicine. For a quick survey oftheir subject matter, see the lists under these three phrasesin the index.

Clinical Applications

It is our primary task in A&P to teach the basic biology ofthe human body, not pathology. Yet students want toknow the relevance of this biology—how it relates totheir career aims. Furthermore, disease often gives us ourmost revealing window on the importance of normalstructure and function. What could better serve than cys-tic fibrosis, for example, to drive home the importance ofmembrane ion pumps? What better than brittle bone dis-ease to teach the importance of collagen in the osseoustissue? The great majority of Insight sidebars thereforedeal with the clinical relevance of the basic biology. Clin-ical content has also been enhanced by the addition of atable for each organ system that describes commonpathologies and page-references others.

Medical History

I found long ago that students especially enjoyed lectures inwhich I remarked on the personal dramas that enliven thehistory of medicine. Thus, I incorporated that approach intomy writing as well, emulating something that is standardfare in introductory biology textbooks but has been largelyabsent from A&P textbooks. Reviews have shown that stu-dents elsewhere, like my own, especially like these stories.I have composed 13 historical and biographical vignettes tohave an especially poignant or inspiring quality, give stu-dents a more humanistic perspective on the field they’vechosen to study, and, I hope, to cultivate an appropriatelythoughtful attitude toward the discipline. Historicalremarks are also scattered through the general text.

Profiles of Marie Curie (p. 58), Rosalind Franklin(p. 132), and Charles Drew (p. 694) tell of the struggles andunkind ironies of their scientific careers. Some of myfavorite historical sidebars are the accounts of William Beau-mont’s digestive experiments on “the man with a hole in hisstomach” (p. 977); Crawford Long’s pioneering surgical useof ether, until then known mainly as a party drug (p. 628);the radical alteration of Phineas Gage’s personality by hisbrain injury (p. 538); and the testy relationship between themen who shared a Nobel Prize for the discovery of insulin,Frederick Banting and J. J. R. MacLeod (p. 671).

Evolutionary Medicine

The human body can never be fully appreciated without asense of how and why it came to be as it is. Medical liter-ature since the mid-1990s has shown increasing interest in“evolutionary medicine,” but most A&P textbooks con-tinue to disregard it. Chapter 1 briefly introduces the con-

Preface xi

cept of natural selection and how certain human adapta-tions relate to our biological past. Later chapters have nineEvolutionary Medicine insights and shorter evolutionaryremarks in the main body of text. Students will find noveland intriguing ways of looking at such topics as mito-chondria (p. 124), hair (p. 204), skeletal anatomy (p. 286),body odors (p. 595), the taste for sweets (p. 990), thenephron loop (p. 897), lactose intolerance (p. 970),menopause (p. 1060), and senescence (p. 1114).

PedagogySeveral features of this book are designed to facilitate thestudent’s learning.

Learning ObjectivesI divide each chapter into typically five or six segments ofjust a few pages each, with a list of learning objectives atthe beginning and a list of “Before You Go On” contentreview questions at the end of each one. This enables stu-dents to set tangible goals for short study periods and toassess their progress before moving on.

Vocabulary AidsA&P students must assimilate a large working vocabulary.This is far easier and more meaningful if they can pro-nounce words correctly and if they understand the rootsthat compose them. Chapter 1 now has a section, “TheLanguage of Medicine,” which I hope will help get stu-dents into the habit of breaking new words into familiarroots, and help them appreciate the importance of preci-sion in spelling and word use. Pronunciation guides aregiven parenthetically when new words are introduced,using a “pro-NUN-see-AY-shun” format that is easy forstudents to interpret. New terms are accompanied by foot-notes that identify their roots and origins, and a lexicon ofabout 400 most commonly used roots and affixes appearsin appendix C (p. A-87).

Self-Testing QuestionsEach chapter has about 75 to 90 self-testing questions invarious formats and three levels of difficulty: recall,description, and analysis or application. The ability torecall terms and facts is tested by 20 multiple choice andsentence completion questions in the chapter review. Theability to describe concepts is tested by the “Before You GoOn” questions at the ends of the chapter subdivisions,totaling about 20 to 30 such questions per chapter. Theability to analyze and apply ideas and to relate concepts indifferent chapters to each other is tested by an average of 5“Think About It” questions at intervals throughout eachchapter, 5 “Testing Your Comprehension” essay questions

at the end of the chapter, 10 “True/False” questions in thechapter review that require the student to analyze why thefalse statements are untrue, and usually 5 questions perchapter in the figure legends, prompting the student to ana-lyze or extrapolate from information in the illustrations. Agreat number and variety of additional questions are avail-able to students at the Online Learning Center.

System InterrelationshipsMost instructors would probably agree on the need toemphasize the interrelationships among organ systemsand to discourage the idea that a system can be put out ofone’s mind after a test is over. This book reinforces theinterdependence of the organ systems in three ways.

1. Beginning with chapter 3 (p. 93), each chapter hasa “Brushing Up” box that lists concepts fromearlier chapters that one should understand beforemoving on. This may also be useful to studentswho are returning to college and need to freshenup concepts studied years before, and toinstructors who teach the systems in a differentorder than the book does. It also reinforces thecontinuity between A&P I and II.

2. For each organ system, there is a “ConnectiveIssues” feature (p. 212, for example) thatsummarizes ways in which that system influencesall of the others of the body, and how it isinfluenced by them in turn.

3. Chapter 29 includes a section, “Senescence of theOrgan Systems,” which can serve as a “capstonelesson” that compellingly shows how the age-related degeneration of each system influences, andis influenced by, the others. Senescence is anincreasingly important topic for health-careproviders as the population increases in averageage. This section should sensitize readers not onlyto the issues of gerontology, but also to measuresthey can take at a young age to ensure a betterquality of life later on. For instructors who prefer totreat senescence of each organ system separatelythroughout the course, earlier chapters cite therelevant pages of this senescence discussion.

What’s New?I’ve been cautious about reorganizing the book and tam-pering with a structure that has been responsible for itssuccess. Nevertheless, the voices of many reviewers haveconvinced me that a few changes were in order.

Changes in Chapter SequenceI made two changes in chapter sequencing and numbering:

xii Preface

Nervous System Chapters

The most frequent request has been to give the autonomicnervous system a chapter of its own, with slightly deepercoverage. I have done so at chapter 15. Another commonrequest I’ve accommodated has been to discuss the spinalcord and spinal nerves together in one chapter (now chap-ter 13) and the brain and cranial nerves together in another(now chapter 14).

Chemistry

To compensate for the added nervous system chapter with-out making the book longer, and because many reviewersfelt that the book could do without two full chapters ofchemistry, I condensed the coverage of chemistry by about25% and combined the two former chemistry chapters intoone (now chapter 2). This results in a change of chapternumbers from 3 through 15, but from chapter 16 to the end,the numbers are the same as in the previous editions.

Changes Within ChaptersIn three cases, I felt that a subject could be presented moreeffectively by rearrangements and content substitutionswithin a chapter. Other chapters continue to be organizedas they were in the second edition.

Chapter 1, Major Themes of Anatomy and Physiology

Here I replaced the section on human taxonomic classifi-cation with sections on anatomical and physiologicalvariability. This gives the chapter a less zoological andmore clinical flavor. Also, I feel it is important at the out-set of such a course to instill a sense of the familiar rootsof biomedical terms, the importance of precision inspelling, and other aspects of vocabulary. Thus I movedthe former appendix B, which introduced students tomedical etymology, to chapter 1 (“The Language of Med-icine,” p. 19).

Chapter 17, The Endocrine System

As many reviewers desired, I have separated endocrinepathology from normal physiology and placed the pathol-ogy at the end of the chapter.

Chapter 21, The Lymphatic and Immune Systems

I have found it more effective to present cellular immunitybefore humoral immunity, since humoral immunitydepends on some concepts such as helper T cells usuallyintroduced in the context of cellular immunity.

Content ChangesI have strengthened the coverage of the following topics(indicating chapter numbers in parentheses): mitochon-drial diseases (3), autoimmune diseases (5), the stages ofhair growth (6), biomechanics of bone tissue (7), the entericnervous system (15), receptive fields of sensory neurons(16), hormone-transport proteins (17), the blood-thymusbarrier (21), clonal deletion and anergy (21), renal autoreg-ulation (23), lipostats and leptin (26), and the trisomies (29).

I have updated information on the following, drawingon research and review literature as recent as April 2002,even as the book was in production: genetic translation inthe nucleus (4), signal peptides (4), stem cell research (5),hair analysis (6), osteoporosis treatments (7), knee surgery(9), muscle–connective tissue relationships (11), mitosis incardiac muscle (11), astrocyte functions (12), surgical treat-ment of parkinsonism (12), amyotrophic lateral sclerosis(13), memory consolidation (14), functional MRI (14), thesensory role of filiform papillae (16), a new class of retinalphotoreceptors (16), the history of anesthesia (16), the rela-tionship of growth hormone to somatomedins (17), cyto-toxic T cell activation (21), asthma (21), neuroimmunology(21), atrial natriuretic peptide (23), hunger and bodyweight homeostasis (26), heritability of alcoholism (26),the functions of relaxin (28), contraceptive options (28),the fate of sperm mitochondria (29), Werner syndrome (29),telomeres (29), and theories of aging (29).

Issues of TerminologyIn 1999, the Terminologia Anatomica (TA) replaced theNomina Anatomica as the international standard foranatomical terminology. I have updated the terminologyin this edition accordingly, except in cases where TA ter-minology is, as yet, so unfamiliar that it may be more ahindrance than a help for an introductory anatomy course.For example, I use the unofficial femur rather than the offi-cial os femoris or femoral bone.

The TA no longer recognizes eponyms, and I haveavoided using them when possible and practical (usingtactile disc instead of Merkel disc, for example). I do intro-duce common eponyms parenthetically when a term isfirst used. Some eponyms are, of course, unavoidable(Alzheimer disease, Golgi complex) and in some cases itstill seems preferable to use the eponyms because of famil-iarity and correlation with other sources that students willread (for example, Schwann cell rather than neurilemmo-cyte).

I follow the recommendation of the American Med-ical Association Manual of Style (ninth edition, 1998) todelete the possessive forms of nearly all eponyms. Thereare people who take offense at the possessive form Down’ssyndrome and yet may be equally insistent thatAlzheimer’s disease be in the possessive. The AMA hasgrappled with such inconsistencies for years, and I accept

its recommendation that the possessives be droppedwhenever possible. I make exception for a few cases suchas Broca’s area (which would be awkward to pronouncewithout the ’s) and I retain the possessive form for naturallaws (Boyle’s law).

Pedagogic ChangesI have made the following changes in pedagogy; see thereferenced pages for examples of each:

• Added icons to the histological illustrations in chapter5 to show a place where each tissue can be found(pp. 162–163).

• Added thought questions to some figure legends(usually five per chapter) and provided answers tothese at the end of the chapter (p. 91).

Suggestions Still Welcome!Many features of this book, and many refinements in thewriting, illustrations, and factual content, came aboutbecause of suggestions and questions from instructors andtheir students. In addition, many things that were triedexperimentally in the first edition have been retained inthe later editions because of positive feedback from users.But perfection in textbook writing seems to be an asymp-tote, ever approached but never fully reached. I invite mycolleagues and students everywhere to continue offeringsuch valuable and stimulating feedback as I continue theapproach.

Ken SaladinDept. of BiologyGeorgia College & State UniversityMilledgeville, Georgia 31061 (USA)478-445-0816ksaladin@gcsu.edu

Teaching and LearningSupplementsMcGraw-Hill offers various tools and technology prod-ucts to support the third edition of Anatomy & Physiol-ogy. Students can order supplemental study materials bycontacting their local bookstore. Instructors can obtainteaching aids by calling the Customer Service Depart-ment, at 800-338-3987, visiting our A&P website atwww.mhhe.com/ap, or contacting their local McGraw-Hill sales representative.

For the Instructor: Instructor’s Presentation CD-ROMThis multimedia collection of visual resources allowsinstructors to utilize artwork from the text in multiple for-mats to create customized classroom presentations, visu-ally based tests and quizzes, dynamic course website con-tent, or attractive printed support materials. The digitalassets on this cross-platform CD-ROM are grouped bychapter within the following easy-to-use folders.

Art Library Full-color digital files of allillustrations in the book, plus the same art saved inunlabeled and gray scale versions, can be readilyincorporated into lecture presentations, exams, orcustom-made classroom materials. These images arealso pre-inserted into blank PowerPoint slides forease of use.Photo Library Digital files of instructionallysignificant photographs from the text—including

Preface xiii

• For each organ system, added a table of pathologieswhich briefly describes several of the most commondysfunctions and cites pages where other dysfunctionsof that system are mentioned elsewhere in the book(p. 208).

• Changed the chapter reviews from an outline to anarrative format that briefly restates the key points ofthe chapter (p. 125).

• Shortened the end-of-chapter vocabulary lists, whichno longer list all boldfaced terms in a chapter, but onlythose terms that I deemed most important (p. 126).

• Added 10 true/false questions to each chapter review,with a prompt to explain why the false questions areuntrue (p. 127). The answers to these are in appendixB (p. 1122).

Na+ 145 mEq/L

K+ 4 mEq/L

K+ 155 mEq/L

Na+ 12 mEq/L

Large anions that cannot escape cell

ECF

ICF

Figure 12.9 Ionic Basis of the Resting Membrane Potential.Note that sodium ions are much more concentrated in the extracellularfluid (ECF) than in the intracellular fluid (ICF), while potassium ions aremore concentrated in the ICF. Large anions unable to penetrate the plasmamembrane give the cytoplasm a negative charge relative to the ECF.If we suddenly increased the concentration of Cl� ions in the ICF, would the membrane potential become higher or lower than the RMP?

cadaver, bone, histology, and surface anatomyimages—can be reproduced for multipleclassroom uses.PowerPoint Lecture Outlines Ready-madepresentations that combine art and lecture notes areprovided for each of the 29 chapters of the text.Written by Sharon Simpson, Broward CommunityCollege, these lectures can be used as they are, orcan be tailored to reflect your preferred lecturetopics and sequences.Table Library Every table that appears in the text isprovided in electronic form.

In addition to the content found within each chapter, theInstructor’s Presentation CD-ROM for Anatomy & Physiologycontains the following multimedia instructional materials:

Active Art Library Active Art consists of art filesfrom key figures from the book that have beenconverted to a format that allows the artwork to beedited inside of Microsoft PowerPoint. Each piece ofart inside an Active Art presentation can be brokendown to its core elements, grouped or ungrouped,and edited to create customized illustrations.Animations Library Numerous full-coloranimations illustrating physiological processes areprovided. Harness the visual impact of processes inmotion by importing these files into classroompresentations or online course materials.

customized exams. This user-friendly program allowsinstructors to search for questions by topic, format, or dif-ficulty level; edit existing questions or add new ones; andscramble questions and answer keys for multiple versionsof the same test. Although few textbook authors write theirown test banks, this test bank, written by the author him-self better reflects the textbook than one contracted out toan independent writer.

Other assets on the Instructor’s Testing and ResourceCD-ROM are grouped within easy-to-use folders. TheInstructor’s Manual and the Instructor’s Manual to accom-pany the Laboratory Manual are available in both Wordand PDF formats. Word files of the test bank are includedfor those instructors who prefer to work outside of the test-generator software.

Laboratory ManualThe Anatomy & Physiology Laboratory Manual by EricWise of Santa Barbara City College is expressly written tocoincide with the chapters of Anatomy & Physiology. Thislab manual has been revised to include clearer explanationsof physiology experiments and computer simulations thatserve as alternatives to frog experimentation. Otherimprovements include a greatly expanded set of reviewquestions at the end of each lab, plus numerous new pho-tographs and artwork.

TransparenciesThis exhaustive set of over 1,000 transparency overheadsincludes every piece of line art in the textbook, tables, andseveral key photographs. An additional set of 150 unla-beled line art duplicates is also available for testing pur-poses or custom labeling. Images are printed with bettervisibility and contrast than ever before, and labels arelarge and bold for clear projection.

English/Spanish Glossary for Anatomy and PhysiologyThis complete glossary includes every key term used in atypical 2-semester anatomy and physiology course. Defin-itions are provided in both English and Spanish. A pho-netic guide to pronunciation follows each word in theglossary.

A Visual Atlas for Anatomy and PhysiologyThis visual atlas contains key gross anatomy illustrationsthat have been blown up in size to make it easier for stu-dents to learn anatomy.

xiv Preface

Instructor’s Testing and Resource CD-ROMThis cross-platform CD-ROM provides a wealth ofresources for the instructor. Supplements featured on thisCD-ROM include a computerized test bank utilizingBrownstone Dipoma@ testing software to quickly create

Clinical Applications ManualExpands on Anatomy and Physiology’s clinical themes,introduces new clinical topics, and provides test ques-tions and case studies to develop the student’s ability toapply his or her knowledge to realistic situations.

Course Delivery SystemsWith help from our partners, WebCT, Blackboard, Top-Class, eCollege, and other course management systems,professors can take complete control over their coursecontent. These course cartridges also provide online test-ing and powerful student tracking features. The SaladinOnline Learning Center is available within all of theseplatforms!

For the Student:MediaPhys CD-ROMThis interactive tool offers detailed explanations, high-quality illustrations, and animations to provide studentswith a thorough introduction to the world of physiology—giving them a virtual tour of physiological processes.MediaPhys is filled with interactive activities and quizzesto help reinforce physiology concepts that are often diffi-cult to understand.

For more information on the outstanding online tools,refer to the front endsheets of your textbook.

GradeSummitGradeSummit, found at www.gradesummit.com, is anInternet-based self-assessment service that provides stu-dents and faculty with diagnostic information about sub-ject strengths and weaknesses. This detailed feedback anddirection enables learners and teachers to focus study timeon areas where it will be most effective. GradeSummit alsoenables instructors to measure their students’ progressand assess that progress relative to others in their classesand worldwide.

Preface xv

Online Learning CenterThe Anatomy & Physiology Online Learning Center (OLC)at www.mhhe.com/saladin3 offers access to a vast array ofpremium online content to fortify the learning and teach-ing experience.

Essential Study Partner A collection of interactivestudy modules that contains hundreds ofanimations, learning activities, and quizzesdesigned to help students grasp complex concepts.Live News Feeds The OLC offers course specificreal-time news articles to help you stay current withthe latest topics in anatomy and physiology.

Student Study GuideThis comprehensive study guide written by JacqueHoman, South Plains College, in collaboration with KenSaladin, contains vocabulary-building and content-testingexercises, labeling exercises, and practice exams.

AcknowledgmentsA textbook and supplements package on this scale is theproduct of a well coordinated effort by many dedicatedpeople. I am deeply indebted to the team at McGraw-HillHigher Education who have shown continued faith in thisbook and invested so generously in it.

For their unfailing encouragement and material sup-port, I thank Vice President and Editor-in-Chief MichaelLange and Publisher Marty Lange. My appreciation like-wise goes out to Michelle Watnick for her years of ener-getic promotion of the book and lately her role as Spon-soring Editor, and to the legion of sales managers and salesrepresentatives who work so hard to get the book into thehands of my fellow instructors and their students.

Kristine Tibbetts, Director of Development, has beena wonderful editor with whom I’ve been very fortunate to

work for the past decade. The appearance of this bookowes a great deal to Kris’s attention to detail and heruncompromising commitment to quality, accuracy, andesthetics. Were it not for e-mail, our voluminous corre-spondence would have required the razing of entire forestsand probably would have detectably enhanced employ-ment statistics for lumberjacks and postal carriers. Work-ing closely with Kris and me, Designer K. Wayne Harmsalso deserves a great deal of credit for the esthetic appealand readability of these pages.

Mary E. Powers, Senior Project Manager, has beenresponsible for monitoring all aspects of the project, keepingme and its many other contributors coordinated and movingtoward the book’s timely release. She, too, has been a veryalert reader of the entire manuscript and has spared no effortto incorporate last-minute corrections and to change pagelayouts for better figure placement and flow of text.

A good copyeditor makes one a better writer, and Ihave learned a great deal from my copyeditors on all edi-tions of this book. On this edition, it was Cathy Conroy’sassiduous attention to detail, ranging from consistency inanatomical synonyms down to the humblest punctuationmark, that spared me from committing numerous embar-rassing errors and inconsistencies.

And always high on my list at McGraw-Hill, I amespecially grateful to Colin Wheatley for his conviction,over a decade ago, that I had a book in me, and for per-suading me to give it a go. Few people have changed mylife so profoundly.

The line art in this edition was beautifully executedby the medical illustrators and graphic artists of Imagi-neering STA Media Services in Toronto, under the watch-ful and knowledgeable eye of Jack Haley, Content/ArtDirector. Imagineering illustrator Dustin Holmes pro-duced the award-winning cover art for the previous edi-tion and, not surprisingly, I was delighted with his execu-tion of the new cover art for this edition. For the visualappeal of this book, credit is also due to McGraw-HillPhoto Coordinator John Leland and Photo ResearcherMary T. Reeg, who worked hard to acquire photographsthat are clear, informative, and esthetically appealing. Imust also repeat my earlier thanks to anatomists Don Kin-caid and Rebecca Gray of the Ohio State UniversityDepartment of Anatomy and Medical Education Morguefor producing at my behest such clean, instructive dissec-tions and clear cadaver photographs.

For photographs of living subjects, whenever possi-ble I employed volunteers from among my own studentsat Georgia College and State University. For kindly lend-ing their bodies to the service of science, I thank my stu-dents, colleagues, friends, and family members: LauraAmmons, Sharesia Bell, Elizabeth Brown, Amy Burmeis-ter, Mae Carpenter, Valeria Champion, Kelli Costa, AdamFraley, Yashica Marshall, Diane Saladin, Emory Saladin,Nicole Saladin, Dilanka Seimon, Natalie Spires, XiaodanWang, Nathan Williams, and Danielle Wychoff. Theimproved photographs of joint movements in this edition(chapter 9), with their multiple-exposure effects, are byMilledgeville photographer Tim Vacula.

Thanks once again to my colleagues David Evans andEric Wise for their fine work in producing the Instructor’sManual and Laboratory Manual, respectively. New thanks toLeslie Miller, M. S. N., for reviewing the manuscript from aclinical perspective and offering many helpful suggestions.

The factual content and accuracy of this edition owea great deal to colleagues who are more knowledgeablethan I in specific areas of human anatomy and physiology,and to both colleagues and inquisitive students whosee-mails and other queries sent me to the library to dig stilldeeper into the literature. I have gained especially fromthe lively and fruitful discussions on HAPP-L, the e-maillist of the Human Anatomy and Physiology Society(http://www.hapsweb.org); my heartfelt thanks go to themany colleagues who have made HAPP-L such a stimulat-ing and informative site, and to Jim Pendley for maintain-ing the list.

Once again, and first in my appreciation, I thank mywife Diane, my son Emory, and my daughter Nicole, not onlyfor sharing with me in the rewards of writing, but also forbearing up so graciously under the demands of having a full-time author cloistered in the inner sanctum of the house.

ReviewersNo words could adequately convey my indebtedness andgratitude to the hundreds of A&P instructors and expertswho have reviewed this book in all its editions, and whohave provided such a wealth of scientific information, cor-rections, suggestions for effective presentation, and encour-agement. For making the book beautiful, I am indebted tothe team described earlier. For making it right, I am thank-ful to the colleagues listed on the following pages.

xvi Preface

Preface xvii

Reviewers from the United StatesMohammed AbbasSchoolcraft CollegeMichael J. Angilletta, Jr.Indiana State UniversityBarbie W. BakerFlorida CommunityCollege–JacksonvilleJoan I. BarberDelaware Technical andCommunity CollegeMary Lou BareitherUniversity of Illinois at ChicagoClifford L. BarnesRegis UniversityJeanne K. BarnettUniversity of Southern IndianaTheresa S. BidleHagerstown Community CollegeWendy D. BircherSan Juan CollegeFranklyn F. Bolander, Jr.University of South CarolinaJoan M. BowdenAlfred UniversityJulie Harrill BowersEast Tennessee State UniversitySheri L. BoyceMessiah CollegeSara BrenizerShelton State CommunityCollegeMelvin K. BrownErie Community College–CityCampusMichael BumbulisBaldwin–Wallace CollegeRay D. BurkettSouthwest TennesseeCommunity CollegeJeanne A. CalvertUniversity of St. FrancisJohn R. CapeheartUniversity ofHouston–DowntownBarbara J. CohenDelaware County CommunityCollegeStephen J. ConnorUniversity of South FloridaW. Wade CooperShelton State CommunityCollegeRedding I. Corbett, IIIMidlands Technical CollegeMarya CzechLourdes CollegeRosemary DavenportGulf Coast Community CollegePatti DavisEast Central Community College

Mary E. DawsonKingsborough CommunityCollegeLarry DeLayWaubonsee Community CollegeNicholas G. DespoThiel CollegeDanielle DesrochesWilliam Paterson University ofNew JerseyWaneene C. DorseyGrambling State UniversityE. Christis FarrellTrevecca Nazarene UniversityDinah T. FarringtonRussell Sage CollegeLorraine FindlayNassau Community CollegePamela B. FouchéWalters State Community CollegeFrederick R. Frank, Jr.Volunteer State CommunityCollegeChristina A. GanRogue Community CollegeChaya GopalanSt. Louis Community CollegeJohn S. GreenTexas A&M UniversityMichael T. GriffinAngelo State UniversityDorothy L. HaggertyDelgado Community CollegeJerry HecklerJohn Carroll UniversityMargery K. HerringtonAdams State CollegeMichael T. HoeferLife UniversityJames HorwitzPalm Beach Community CollegeAllen N. HuntElizabethtown CommunityCollegeSarah Caruthers JacksonFlorida CommunityCollege–JacksonvilleKenneth KaloustianQuinnipiac UniversityD. T. KidwellSoutheast Community CollegeKris A. KilibardaIowa Western Community CollegeShelley A. KirkpatrickSaint Francis UniversityThomas E. KoberCincinnati State Technical andCommunity CollegeMarian G. LangerSaint Francis University

Waiston C. LeeWayne Community CollegeAdam LeffKent State University–TrumbullCampusSteven D. LeidichCuyahaga Community CollegeClaire LeonardWilliam Paterson UniversityAlex LowreyGainesville CollegeD. J. Lowrie, Jr.University of CincinnatiJennifer LundmarkCalifornia StateUniversity–SacramentoChristopher L. McNairHardin–Simmons UniversityGlenn MerrickLake Superior CollegeLee A. MeserveBowling Green State UniversityMindy Millard-StaffordGeorgia TechMelissa A. MillsAnoka–Ramsey CommunityCollegeRobert MoldenhauerSaint Clair County CommunityCollegeDavid P. Sogn MorkSt. Cloud State UniversityDevonna Sue MorraSaint Francis UniversityLinda R. NicholsSanta Fe Community CollegeMurad OdehSouth Texas Community CollegeRandall OelerichLake Superior CollegeNathan O. OkiaAuburn University MontgomeryValerie Dean O’LoughlinIndiana University–BloomingtonDonald M. O’MalleyNortheastern UniversityMargaret (Betsy) OttTyler Junior CollegeDavid PearsonBall State UniversityJulie C. PilcherUniversity of Southern IndianaDon V. Plantz, Jr.Mohave Community CollegeNikki PrivackyPalm Beach Community CollegeGregory K. ReederBroward Community CollegeTricia A. ReichertColby Community College

Jackie ReynoldsRichland CollegeS. Michele RobichauxNicholls State UniversityAngel M. RodriguezBroward Community CollegeMattie RoigBroward Community CollegeTim V. RoyeSan Jacinto College SouthSusan E. SaffordLincoln UniversityDouglas P. SchelhaasUniversity of MaryWaweise SchmidtPalm Beach Community CollegeWilliam A. Schutt, Jr.Southampton College of LongIsland UniversityLarry J. ScottCentral Virginia CommunityCollegeJosefina Z. Sevilla-GardinierMilwaukee Area TechnicalCollegeKelly SextonNorth Lake CollegeMark A. ShoopTennessee Wesleyan CollegeCarl J. ShusterAmarillo CollegeDale SmoakPiedmont Technical CollegeKeith SnyderSouthern Adventist UniversityTracy L. SolteszPikeville CollegeMichael W. SquiresColumbus State CommunityCollegeTimothy A. StablerIndiana University NorthwestJohn E. StencelOlney Central CollegeMaura O. StevensonCommunity College ofAllegheny CountyWilliam StewartMiddle Tennessee StateUniversityRobert StinsonSouth Texas Community CollegeKristin J. StuempfleGettysburg CollegeMark F. TaylorBaylor UniversityDiane TeterSouth Texas Community CollegeShawn A. ThomasDelta State University

xviii Preface

Rafael TorresSan Antonio CollegeAnthony UdeogalanyaMedgar Evers CollegeJohn UnoKapiolani Community CollegeJyoti R. WagleHouston CommunityCollege–CentralJohn M. WakemanLouisiana Tech UniversityWilliam G. WaltherLake Erie CollegeRobert WaltzerBelhaven College

DeLoris WenzelUniversity of GeorgiaVernon Lee WiersemaHouston CommunityCollege–SouthwestAvery A. WilliamsLouisiana StateUniversity–EuniceBruce Eric WrightThomas UniversityBurk YarbroughCentral Alabama CommunityCollege–Childersburg CampusFerne ZabezenskyChandler–Gilbert CommunityCollege

Focus Group Attendees

Reviewers from CanadaMargaret ChadSaskatchewan Institute ofApplied Science andTechnology–Kelsey CampusMary T. GuiseMohawk College of AppliedArts and TechnologyNarinder KapoorUniversity Concordia

Linda MelnickKeewatin Community CollegeDelia RobertsSelkirk CollegeT. M. ScottMemorial University

Reviewers from Outside North AmericaM. AbbottNottingham University, Schoolof NursingIrene AllanUniversity of Dundee School of Nursing and MidwiferyR. K. AtkinsonUniversity of SouthernQueenslandDarwish H. BadranUniversity of Jordan, MedicalCollegeA. D. BarberPlymouth School of PodiatryDouglas L. BovellGlasgow Caledonian UniversityRichard BrightwellEdith Cowan UniversityMark A. BurtonCharles Sturt University, Schoolof Biomedical SciencesChristine Lorraine CarlineStaffordshire University, Schoolof HealthDavid ColbornIndependent Consultant, Healthand Social CareDesmond CornesGlasgow Caledonian University

Michele DonGriffith University, School of NursingJan S. GillQueen Margaret UniversityCollegeHelen GodfreyUniversity of the West of EnglandD. F. PeachCranfield UniversityDavid M. QuinceyBournemouth UniversityDavid RobertsonThe Robert Gordon UniversitySchool of Health SciencesGeorge SimpsonLiverpool John MooresUniversityPaul SlaterUniversity of ManchesterRoger WatsonUniversity of Hull, School ofNursingAnne WaughNapier UniversityChris G. WighamCardiff University

Shylaja R. AkkarajuCollege of DupageLes AlbinAustin Community CollegePegge AlciatoreUniversity of Louisiana-LafayetteBarbie W. BakerFlorida Community College-JacksonvilleRobert Bauman, Jr.Amarillo CollegeMary BrackenTrinity Valley Community CollegeKenneth CarpenterSouthwest TennesseeCommunity CollegeMatthew J. CraigAmarillo CollegeManuel E. Daniels, Jr.Tallahassee Community CollegeKathryn GronlundEdison Community CollegeRebecca L. HennigOdessa CollegeJacqueline A. HomanSouth Plains CollegeJane Johnson-MurrayHouston Community CollegeCentral Christopher A. KlotzSt. Petersburg CollegeChad M. MastersUniversity of North FloridaElizabeth J. MaximAustin Community CollegeRichard McCloskeyBoise State UniversityW. J. McCrackenTallahassee Community CollegeLynn McCutchenKilgore College

Anthony P. McGrawSaint Petersburg CollegeRobert C. McReynoldsSan Jacinto College CentralStephen H. McReynoldsTarleton State UniversityJohn E. MooreParkland CollegeMargaret (Betsy) OttTyler Junior CollegeJulie C. PilcherUniversity of Southern IndianaLinda PowellCommunity College ofPhiladelphiaMattie RoigBroward Community CollegeWayne SeifertBrookhaven CollegeSusan ShumanSt. Petersburg CollegeCarl J. ShusterAmarillo CollegeWilliam StewartMiddle Tennesse State UniversitySarah StrongAustin Community CollegeJyoti R. WagleHouston Community CollegeCentral Donna WhiteCollin County CommunityCollegeKathy B. WhiteSt. Philips CollegeVernon Lee WiersemaHouston CommunityCollege–SouthwestStephen WilliamsGlendale Community CollegeJim YoungSouth Plains College

Consultant PanelBarbie W. BakerFlorida CommunityCollege–JacksonvilleSharon BarnewallColumbus State CommunityCollegeFranklyn F. Bolander, Jr.University of South CarolinaSara BrenizerShelton State Community CollegeFrederick R. Frank, Jr.Volunteer State CommunityCollegeCarol HaspelLaGuardia Community College,CUNYDon HayesSoutheastern Louisiana University

Jacqueline A. HomanSouth Plains CollegeJames HorwitzPalm Beach Community CollegeWilliam MagillHumber CollegeJohn E. MooreParkland CollegeMargaret (Betsy) OttTyler Junior CollegeMattie RoigBroward Community CollegeEva Lurie WeinrebCommunity College ofPhiladelphiaVernon Lee WiersemaHouston CommunityCollege–Southwest

Saladin’s Anatomy and Physiology brings keyconcepts to life with its unique style ofbiomedical illustration.The digitally renderedimages have a vivid three-dimensional lookthat will not only stimulate your students’interest and enthusiasm, but also give themthe clearest possible understanding ofimportant concepts.

Unparalleled Art ProgramSaladin’s illustration program includes digitalline art, numerous cadaver photographs, andlight,TEM, and SEM photomicrographs. Largerimages and brighter colors in the thirdedition will help draw your students into thesubject.

I must say I was completely blown away by this text.The graphics in [a leading text I’ve been using]don’t come close to the graphics in Saladin (whichhave an extraordinary 3-D quality).

–Bill Schutt, Long Island University

xx Preface

The art program in Saladin’s text is superb. Studentstoday are more “picture oriented” and gain much oftheir information from the figures rather than from thetext material. The figures in Saladin are clearly andaccurately presented.

W. Walther, Lake Erie College

Atlas Quality Cadaver ImagesColor photographs of cadavers dissectedspecifically for this book allow students tosee the real texture of organs and theirrelationships to each other.This anatomicalrealism combines with the simplified clarityof line art to give your students a holisticview of bodily structure.

The cadaver photos are excellent! My students(and friends who have taught or taken anatomyclass) love them.

–Michael Angilletta, Jr., Indiana State University,Terre Haute

Students have liked the excellent artwork, the chartsand tables, and the clinical insights.Thephotographs of cadaver dissections and theelectron microscopy are excellent.

- Robert Moldenhauer, St. Clair County CommunityCollege

Physiology Focused ArtSaladin illustrates many difficult physiologicalconcepts in steps that students find easy tofollow. For students who are "visual learners,"illustrations like these teach more than athousand words.

One of the major strengths of the Saladin text, onethat promoted me to adopt the text, was the qualityand quantity of the illustrations. In my view, this textis a hands-down winner in this area.

R. Symmons, California State University at Hayward

MicrographsAll life processes are ultimately cellular processes. Saladindrives this point home with a variety of histologicalmicrograp hs in LM, SEM, and TEM formats, including manycolorized electron micrographs.

Photomicrographs Correlated with Line ArtSaladin juxtaposes histologicalphotomicrographs with line art. Much like thecombination of cadaver gross photographs andline art, this gives students the best of bothperspectives: the realism of photos and theexplanatory clarity of line drawings.

From Macroscopic to MicroscopicSaladin’s line art guides students from the intuitive level of grossanatomy to the functional foundations revealed by microscopicanatomy.

The artwork in Saladin is one of its major strengths. Iapplaud this; it really seems to help hold the interest ofa wide variety of students.

D. Farrington, Russell Sage College

Anatomy and Physiology is fundamentally atextbook of the basic science of the humanbody. However, students always want toknow why all the science is relevant to theircareer aims. Clinical examples and thoughtquestions make it so. Students can see howthe science relates to well-knowndysfunctions, and why it is important toknow the basics. Dysfunctions also providewindows of insight into the basic concepts,such as the insight that cystic fibrosis giveson the importance of membrane ionchannels, or that antidepressants give onthe synaptic reuptake of neurotransmitters.

Pathology TablesFor each organ system, Saladin presents atable that briefly describes several well-known dysfunctions and comprehensivelylists the pages where students can findcomments on other disorders of thatsystem.

There are many tidbits of clinicalinformation that are in this book, but notin others that I have seen. I think that’sgreat! I have learned a thing or two. Ialso think that the author has tried tochoose clinical examples that arecommonly dealt with and thereforemost useful to the student.

L. Steele, Ivy Tech State College

Cha

pte

r 11

Smooth muscle exhibits a reaction called the stress-relaxation (or receptive relaxation) response. Whenstretched, it briefly contracts and resists, but then relaxes.The significance of this response is apparent in the uri-nary bladder, whose wall consists of three layers ofsmooth muscle. If the stretched bladder contracted anddid not soon relax, it would expel urine almost as soon asit began to fill, thus failing to store the urine until anopportune time.

Remember that skeletal muscle cannot contract veryforcefully if it is overstretched. Smooth muscle is not sub-ject to the limitations of this length-tension relationship. Itmust be able to contract forcefully even when greatlystretched, so that hollow organs such as the stomach andbladder can fill and then expel their contents efficiently.Skeletal muscle must be within 30% of optimum length inorder to contract strongly when stimulated. Smooth mus-cle, by contrast, can be anywhere from half to twice itsresting length and still contract powerfully. There arethree reasons for this: (1) there are no Z discs, so thick fil-aments cannot butt against them and stop the contraction;(2) since the thick and thin filaments are not arranged inorderly sarcomeres, stretching of the muscle does notcause a situation where there is too little overlap for cross-bridges to form; and (3) the thick filaments of smooth

muscle have myosin heads along their entire length (thereis no bare zone), so cross-bridges can form anywhere, notjust at the ends. Smooth muscle also exhibits plasticity—the ability to adjust its tension to the degree of stretch.Thus, a hollow organ such as the bladder can be greatlystretched yet not become flabby when it is empty.

The muscular system suffers fewer diseases than anyother organ system, but several of its more common dys-functions are listed in table 11.6. The effects of aging onthe muscular system are described on pages 1109–1110.

Before You Go OnAnswer the following questions to test your understanding of thepreceding section:25. Explain why intercalated discs are important to cardiac muscle

function.26. Explain why it is important for cardiac muscle to have a longer

action potential and longer refractory period than skeletal muscle.27. How do single-unit and multiunit smooth muscle differ in

innervation and contractile behavior?28. How does smooth muscle differ from skeletal muscle with

respect to its source of calcium and its calcium receptor?29. Explain why the stress-relaxation response is an important factor

in smooth muscle function.

436 Part Two Support and Movement

Table 11.6 Some Disorders of the Muscular System

Delayed onset muscle Pain, stiffness, and tenderness felt from several hours to a day after strenuous exercise. Associated with microtrauma to soreness the muscles, with disrupted Z discs, myofibrils, and plasma membranes; and with elevated levels of myoglobin, creatine

kinase, and lactate dehydrogenase in the blood.

Cramps Painful muscle spasms triggered by heavy exercise, extreme cold, dehydration, electrolyte loss, low blood glucose, or lack of blood flow.

Contracture Abnormal muscle shortening not caused by nervous stimulation. Can result from failure of the calcium pump to remove Ca2� from the sarcoplasm or from contraction of scar tissue, as in burn patients.

Fibromyalgia Diffuse, chronic muscular pain and tenderness, often associated with sleep disturbances and fatigue; often misdiagnosed as chronic fatigue syndrome. Can be caused by various infectious diseases, physical or emotional trauma, or medications. Most common in women 30 to 50 years old.

Crush syndrome A shocklike state following the massive crushing of muscles; associated with high and potentially fatal fever, cardiac irregularities resulting from K� released from the muscle, and kidney failure resulting from blockage of the renal tubuleswith myoglobin released by the traumatized muscle. Myoglobinuria (myoglobin in the urine) is a common sign.

Disuse atrophy Reduction in the size of muscle fibers as a result of nerve damage or muscular inactivity, for example in limbs in a cast and in patients confined to a bed or wheelchair. Muscle strength can be lost at a rate of 3% per day of bed rest.

Myositis Muscle inflammation and weakness resulting from infection or autoimmune disease.

Disorders described elsewhere

Athletic injuries p. 386 Hernia p. 351 Pulled groin p. 386

Back injuries p. 349 Muscular dystrophy p. 437 Pulled hamstrings p. 386

Baseball finger p. 386 Myasthenia gravis p. 437 Rotator cuff injury p. 386

Carpal tunnel syndrome p. 365 Paralysis p. 414 Tennis elbow p. 386

Charley horse p. 386 Pitcher’s arm p. 386 Tennis leg p. 386

Compartment syndrome p. 386

with myoglobin released by the traumatized muscl

Disuse atrophy Reduction in the size of muscle fibers as a result of nin patients confined to a bed or wheelchair. Muscle

Myositis Muscle inflammation and weakness resulting from in

Disorders described elsewhere

Athletic injuries p. 386 Hernia p. 351 Pulled gr

Back injuries p. 349 Muscular dystrophy p. 437 Pulled ha

Baseball finger p. 386 Myasthenia gravis p. 437 Rotator c

Carpal tunnel syndrome p. 365 Paralysis p. 414 Tennis e

Charley horse p. 386 Pitcher’s arm p. 386 Tennis le

Compartment syndrome p. 386

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Chapter 10 The Muscular System 351

erection. In males, the bulbospongiosus (bulbocavernosus)forms a sheath around the base (bulb) of the penis; it expelssemen during ejaculation. In females, it encloses the vaginalike a pair of parentheses and tightens on the penis duringintercourse. Voluntary contractions of this muscle in bothsexes also help void the last few milliliters of urine. Thesuperficial transverse perineus extends from the ischialtuberosities to a strong central tendon of the perineum.

In the middle compartment, the urogenital triangle isspanned by a thin triangular sheet called the urogenitaldiaphragm. This is composed of a fibrous membrane andtwo muscles—the deep transverse perineus and the exter-nal urethral sphincter (fig. 10.20c, d). The anal trianglecontains the external anal sphincter. The deepest com-partment, called the pelvic diaphragm, is similar in bothsexes. It consists of two muscle pairs shown in figure10.20e—the levator ani and coccygeus.

Insight 10.3 Clinical Application

Hernias

A hernia is any condition in which the viscera protrude through a weakpoint in the muscular wall of the abdominopelvic cavity. The mostcommon type to require treatment is an inguinal hernia. In the malefetus, each testis descends from the pelvic cavity into the scrotum byway of a passage called the inguinal canal through the muscles of thegroin. This canal remains a weak point in the pelvic floor, especially ininfants and children. When pressure rises in the abdominal cavity, itcan force part of the intestine or bladder into this canal or even intothe scrotum. This also sometimes occurs in men who hold their breathwhile lifting heavy weights. When the diaphragm and abdominal mus-cles contract, pressure in the abdominal cavity can soar to 1,500pounds per square inch—more than 100 times the normal pressure andquite sufficient to produce an inguinal hernia, or “rupture.” Inguinalhernias rarely occur in women.

Longissimus capitisSemispinalis capitis

Internal abdominal oblique

Erector spinaeSemispinalis thoracis

Multifidus

Quadratus lumborum

Superior nuchal line

Splenius capitis

Serratus posterior superior

Splenius cervicis

External abdominaloblique (cut)

Semispinalis cervicis

Serratus posterior inferior

Iliocostalis

Longissimus

Spinalis

Figure 10.18 Muscles Acting on the Vertebral Column. Those on the right are deeper than those on the left.

Clinical ApplicationsEach chapter has three to five Insightboxes, many of which are clinical in na-ture. These essays illuminate the clinicalrelevance of a concept and give insighton disease as it relates to normal struc-ture and function.

The accuracy of information in this text isas good as it gets. Saladin seems to beright on top of every new bit ofinformation that is revealed.What I reallylike about the Saladin text is that it letsstudents know when we don’t know whysomething is the way it is. Other texts willtry to make the facts fit when theyactually don’t.

– W. Schmidt, Palm Beach CommunityCollege

I like Saladin’s presentation because Ifeel an understanding of how medicineand science have changed throughouthistory is part of becoming a "welleducated," not just a "well trained"student.

- R. Pope, Miami-Dade Community College

ernosus)it expels

he vaginas during

e in bothine. Thee ischialeum.iangle isogenital

rane andhe exter-triangle

est com-r in both

Insight 10.3 Clinical Application

Hernias

A hernia is any condition in which the viscera protrude through a weakpoint in the muscular wall of the abdominopelvic cavity. The mostcommon type to require treatment is an inguinal hernia. In the malefetus, each testis descends from the pelvic cavity into the scrotum byway of a passage called the inguinal canal through the muscles of thegroin. This canal remains a weak point in the pelvic floor, especially ininfants and children. When pressure rises in the abdominal cavity, itcan force part of the intestine or bladder into this canal or even intothe scrotum. This also sometimes occurs in men who hold their breathwhile lifting heavy weights. When the diaphragm and abdominal mus-cles contract, pressure in the abdominal cavity can soar to 1,500pounds per square inch—more than 100 times the normal pressure and

All SystemsThe respiratory system serves all other systems by supplying O2,removing CO2, and maintaining acid-base balance

Integumentary SystemNasal guard hairs reduce inhalation of dust and other foreignmatter

Skeletal SystemThoracic cage protects lungs; movement of ribs produces pressurechanges that ventilate lungs

Muscular SystemSkeletal muscles ventilate lungs, control position of larynx duringswallowing, control vocal cords during speech; exercise stronglystimulates respiration because of the CO2 generated by activemuscles

Nervous SystemProduces the respiratory rhythm, monitors blood gases and pH,monitors stretching of lungs; phrenic, intercostal, and other nervescontrol respiratory muscles

Endocrine SystemLungs produce angiotensin-converting enzyme (ACE), whichconverts angiotensin I to the hormone angiotensin II

Epinephrine and norepinephrine dilate bronchioles and stimulateventilation

Circulatory SystemRegulates blood pH; thoracic pump aids in venous return; lungs produce blood platelets; production of angiotensin II bylungs is important in control of blood volume and pressure;obstruction of pulmonary circulation leads to right-sided heartfailure

Blood transports O2 and CO2; mitral stenosis or left-sided heartfailure can cause pulmonary edema; emboli from peripheral sitesoften lodge in lungs

Lymphatic/Immune SystemsThoracic pump promotes lymph flow

Lymphatic drainage from lungs is important in keeping alveoli dry;immune cells protect lungs from infection

Urinary SystemValsalva maneuver aids in emptying bladder

Disposes of wastes from respiratory organs; collaborates withlungs in controlling blood pH

Digestive SystemValsalva maneuver aids in defecation

Provides nutrients for growth and maintenance of respiratorysystem

Reproductive SystemValsalva maneuver aids in childbirth

Sexual arousal stimulates respiration

Interactions Between the RESPIRATORY SYSTEM and Other Organ Systems

indicates ways in which this system affects other systemsindicates ways in which other systems affect this one

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873

Connective IssuesThe human organ systems do not exist in iso-lation from each other. Diseases of the circu-latory system can lead to failure of the urinarysystem and aging of the skin can lead toweakening of the skeleton. For each organsystem, a page called Connective Issuesshows how it affects other systems of thebody and is affected by them.

Think About ItSuccess in health professions requires farmore than memorization. More important isyour insight and ability to apply what you re-member in new cases and problems. ThinkAbout iIt questions, which can be foundstrategically distributed throughout eachchapter, encourage stopping and thinkingmore deeply about the meaning or broadersignificance.

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This section describes the neural mechanisms thatregulate pulmonary ventilation. Neurons in the medullaoblongata and pons provide automatic control of uncon-scious breathing, whereas neurons in the motor cortex ofthe cerebrum provide voluntary control.

Control Centers in the BrainstemThe medulla oblongata contains inspiratory (I) neurons,which fire during inspiration, and expiratory (E) neurons,which fire during forced expiration (but not during eup-nea). Fibers from these neurons travel down the spinalcord and synapse with lower motor neurons in the cervi-cal to thoracic regions. From here, nerve fibers travel inthe phrenic nerves to the diaphragm and intercostalnerves to the intercostal muscles. No pacemaker neuronshave been found that are analogous to the autorhythmiccells of the heart, and the exact mechanism for setting therhythm of respiration remains unknown despite intensiveresearch.

The medulla has two respiratory nuclei (fig. 22.15).One of them, called the inspiratory center, or dorsal re-spiratory group (DRG), is composed primarily of I neu-rons, which stimulate the muscles of inspiration. The morefrequently they fire, the more motor units are recruitedand the more deeply you inhale. If they fire longer thanusual, each breath is prolonged and the respiratory rate isslower. When they stop firing, elastic recoil of the lungsand thoracic cage produces passive expiration.

The other nucleus is the expiratory center, or ventralrespiratory group (VRG). It has I neurons in its midregionand E neurons at its rostral and caudal ends. It is notinvolved in eupnea, but its E neurons inhibit the inspira-tory center when deeper expiration is needed. Conversely,the inspiratory center inhibits the expiratory center whenan unusually deep inspiration is needed.

The pons regulates ventilation by means of a pneu-motaxic center in the upper pons and an apneustic (ap-NEW-stic) center in the lower pons. The role of theapneustic center is still unclear, but it seems to prolonginspiration. The pneumotaxic (NEW-mo-TAX-ic) centersends a continual stream of inhibitory impulses to theinspiratory center of the medulla. When impulse fre-quency rises, inspiration lasts as little as 0.5 second andthe breathing becomes faster and shallower. Conversely,when impulse frequency declines, breathing is slower anddeeper, with inspiration lasting as long as 5 seconds.

Think About ItDo you think the fibers from the pneumotaxic centerproduce EPSPs or IPSPs at their synapses in theinspiratory center? Explain.

858 Part Four Regulation and Maintenance

PonsMedulla

Pneumotaxic center

Apneustic center

Expiratory center

Inspiratory center

+

+

+

+

Internal intercostalmuscles

External intercostalmuscles

+ Excitation

Inhibition

Diaphragm

Figure 22.15 Respiratory Control Centers. Functions of theapneustic center are hypothetical and its connections are thereforeindicated by broken lines. As indicated by the plus and minus signs, theapneustic center stimulates the inspiratory center, while the pneumotaxiccenter inhibits it. The inspiratory and expiratory centers inhibit eachother.

quency rises, inspiration lasts as little as 0.5 second andthe breathing becomes faster and shallower. Conversely,when impulse frequency declines, breathing is slower anddeeper, with inspiration lasting as long as 5 seconds.

Think About ItDo you think the fibers from the pneumotaxic centerproduce EPSPs or IPSPs at their synapses in theinspiratory center? Explain.

The clinical application approach seems much moreconsistently and richly in evidence in Saladin.

- D. Plantz, Mohave Community College

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This section describes the neural mechanisms thatregulate pulmonary ventilation. Neurons in the medullaoblongata and pons provide automatic control of uncon-scious breathing, whereas neurons in the motor cortex ofthe cerebrum provide voluntary control.

Control Centers in the BrainstemThe medulla oblongata contains inspiratory (I) neurons,which fire during inspiration, and expiratory (E) neurons,which fire during forced expiration (but not during eup-nea). Fibers from these neurons travel down the spinalcord and synapse with lower motor neurons in the cervi-cal to thoracic regions. From here, nerve fibers travel inthe phrenic nerves to the diaphragm and intercostalnerves to the intercostal muscles. No pacemaker neuronshave been found that are analogous to the autorhythmiccells of the heart, and the exact mechanism for setting therhythm of respiration remains unknown despite intensiveresearch.

The medulla has two respiratory nuclei (fig. 22.15).One of them, called the inspiratory center, or dorsal re-spiratory group (DRG), is composed primarily of I neu-rons, which stimulate the muscles of inspiration. The morefrequently they fire, the more motor units are recruitedand the more deeply you inhale. If they fire longer thanusual, each breath is prolonged and the respiratory rate isslower. When they stop firing, elastic recoil of the lungsand thoracic cage produces passive expiration.

The other nucleus is the expiratory center, or ventralrespiratory group (VRG). It has I neurons in its midregionand E neurons at its rostral and caudal ends. It is notinvolved in eupnea, but its E neurons inhibit the inspira-tory center when deeper expiration is needed. Conversely,the inspiratory center inhibits the expiratory center whenan unusually deep inspiration is needed.

The pons regulates ventilation by means of a pneu-motaxic center in the upper pons and an apneustic (ap-NEW-stic) center in the lower pons. The role of theapneustic center is still unclear, but it seems to prolonginspiration. The pneumotaxic (NEW-mo-TAX-ic) centersends a continual stream of inhibitory impulses to theinspiratory center of the medulla. When impulse fre-quency rises, inspiration lasts as little as 0.5 second andthe breathing becomes faster and shallower. Conversely,when impulse frequency declines, breathing is slower anddeeper, with inspiration lasting as long as 5 seconds.

Think About ItDo you think the fibers from the pneumotaxic centerproduce EPSPs or IPSPs at their synapses in theinspiratory center? Explain.

858 Part Four Regulation and Maintenance

PonsMedulla

Pneumotaxic center

Apneustic center

Expiratory center

Inspiratory center

+

+

+

+

Internal intercostalmuscles

External intercostalmuscles

+ Excitation

Inhibition

Diaphragm

Figure 22.15 Respiratory Control Centers. Functions of theapneustic center are hypothetical and its connections are thereforeindicated by broken lines. As indicated by the plus and minus signs, theapneustic center stimulates the inspiratory center, while the pneumotaxiccenter inhibits it. The inspiratory and expiratory centers inhibit eachother.

Pedagogical Aids Promote Systematic LearningSaladin structures each chapter around a consistent andunique framework of pedagogic devices. No matter whatthe subject matter of a chapter, this enables students todevelop a consistent learning strategy, making Anatomyand Physiology a superior learning tool.

Chapter OutlineAn outline of the first chapter of each page provides abroad overview of twhat is covered. Page-referenced to fa-cilitate later review and study. Saladin often presents con-cepts as bulleted or numbered lists. Students find they canabsorb key points more easily from these than from a con-tinuous narrative.

InsightsEach chapter has from three to six special topic Insight es-says on the history behind the science, the evolution be-hind human form and function, and especially the clinicalimplications of the basic science. Insight sidebars lend thesubject deeper meaning, intriguing perspectives, and ca-reer relevance to the student.

Brushing UpA Brushing Up list at the beginning of the chapter tieschapters together and reminds students that all organ sys-tems are conceptually related to each other.They discour-age the habit of forgetting about a chapter after the examis over. Brushing Up lists are also useful to instructors whopresent the subject in a different order from the textbook.

page 515

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This section describes the neural mechanisms thatregulate pulmonary ventilation. Neurons in the medullaoblongata and pons provide automatic control of uncon-scious breathing, whereas neurons in the motor cortex ofthe cerebrum provide voluntary control.

Control Centers in the BrainstemThe medulla oblongata contains inspiratory (I) neurons,which fire during inspiration, and expiratory (E) neurons,which fire during forced expiration (but not during eup-nea). Fibers from these neurons travel down the spinalcord and synapse with lower motor neurons in the cervi-cal to thoracic regions. From here, nerve fibers travel inthe phrenic nerves to the diaphragm and intercostalnerves to the intercostal muscles. No pacemaker neuronshave been found that are analogous to the autorhythmiccells of the heart, and the exact mechanism for setting therhythm of respiration remains unknown despite intensiveresearch.

The medulla has two respiratory nuclei (fig. 22.15).One of them, called the inspiratory center, or dorsal re-spiratory group (DRG), is composed primarily of I neu-rons, which stimulate the muscles of inspiration. The morefrequently they fire, the more motor units are recruitedand the more deeply you inhale. If they fire longer thanusual, each breath is prolonged and the respiratory rate isslower. When they stop firing, elastic recoil of the lungsand thoracic cage produces passive expiration.

The other nucleus is the expiratory center, or ventralrespiratory group (VRG). It has I neurons in its midregionand E neurons at its rostral and caudal ends. It is notinvolved in eupnea, but its E neurons inhibit the inspira-tory center when deeper expiration is needed. Conversely,the inspiratory center inhibits the expiratory center whenan unusually deep inspiration is needed.

The pons regulates ventilation by means of a pneu-motaxic center in the upper pons and an apneustic (ap-NEW-stic) center in the lower pons. The role of theapneustic center is still unclear, but it seems to prolonginspiration. The pneumotaxic (NEW-mo-TAX-ic) centersends a continual stream of inhibitory impulses to theinspiratory center of the medulla. When impulse fre-quency rises, inspiration lasts as little as 0.5 second andthe breathing becomes faster and shallower. Conversely,when impulse frequency declines, breathing is slower anddeeper, with inspiration lasting as long as 5 seconds.

Think About ItDo you think the fibers from the pneumotaxic centerproduce EPSPs or IPSPs at their synapses in theinspiratory center? Explain.

858 Part Four Regulation and Maintenance

PonsMedulla

Pneumotaxic center

Apneustic center

Expiratory center

Inspiratory center

+

+

+

+

Internal intercostalmuscles

External intercostalmuscles

+ Excitation

Inhibition

Diaphragm

Figure 22.15 Respiratory Control Centers. Functions of theapneustic center are hypothetical and its connections are thereforeindicated by broken lines. As indicated by the plus and minus signs, theapneustic center stimulates the inspiratory center, while the pneumotaxiccenter inhibits it. The inspiratory and expiratory centers inhibit eachother.

page 529

Before You Go OnSaladin divides each chapter into short "digestible" seg-ments of about three to five pages each. Each segmentends with a few content review questions, so students canpause to evaluate their understanding of the previous fewpages before going on.

ObjectivesEach new section of a chapter begins with a list of learningobjectives. Students and instructors find this more usefulthan a single list of objectives at the beginning of a chap-ter, where few students ever refer back to them as theyprogress with their reading.

I really like having the objectives listed prior to each sec-tion instead of in the beginning of each chapter. In thismanner, they are more appropriate for the students and ithelps them focus on the issues of importance of that sec-tion. The "Think About It" questions are especially nice as itmakes the students stop and apply what they have read.

- W. Bircher, San Juan College

Chapter ReviewBriefly restates the key points of thechapter.

Testing Your RecallMultiple choice and short answerquestions allow students to checktheir knowledge.

Testing Your ComprehensionQuestions that go beyondmemorization to require a deeperlevel of analysis and clinicalapplication. Scenarios fromMorbidity and Mortality WeeklyReports and other sources promptstudents to apply the chapter’s basicscience to real-life case histories.

True or FalseSaladin’s True or False questions aremore than they appear.They alsorequire the student to explain whythe false statements are untrue, thuschallenging the student to thinkmore deeply into the material and toappreciate and express subtlepoints.Answers can be found in theappendix.

Answers to Figure Legend QuestionsThought questions have been added to aroundfive figures per chapter. Answers to thesequestions are found in this section.

Web AddressLocated at the end of the Chapter Review is areminder that additional study questions andother learning activities for anatomy andphysiology appear on the Online LearningCenter.

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558 Part Three Integration and Control

Overview of the Brain (p. 516)1. The adult brain weighs 1,450 to

1,600 g. It is divided into thecerebrum, cerebellum, and brainstem.

2. The cerebrum and cerebellum exhibitfolds called gyri separated by groovescalled sulci. The groove between thecerebral hemispheres is thelongitudinal fissure.

3. The cerebrum and cerebellum havegray matter in their surface cortexand deeper nuclei, and white matterdeep to the cortex.

4. Embryonic development of the brainprogresses through neural plate andneural tube stages in the first 4weeks. The anterior neural tube thenbegins to bulge and differentiate intoforebrain, midbrain, and hindbrain.By the fifth week, the forebrain andhindbrain show further subdivisioninto two secondary vesicles each.

Meninges, Ventricles, CerebrospinalFluid, and Blood Supply (p. 519)1. Like the spinal cord, the brain is

surrounded by a dura mater,arachnoid mater, and pia mater. Thedura mater is divided into two layers,periosteal and meningeal, which insome places are separated by a blood-filled dural sinus. In some places, asubdural space also separates thedura from the arachnoid.

2. The brain has four internal,interconnected cavities: two lateralventricles in the cerebralhemispheres, a third ventriclebetween the hemispheres, and afourth ventricle between the pons andcerebellum.

3. The ventricles and canals of the CNSare lined with ependymal cells, andeach ventricle contains a choroidplexus of blood capillaries.

4. These spaces are filled withcerebrospinal fluid (CSF), which isproduced by the ependyma andchoroid plexuses and in thesubarachnoid space around the brain.The CSF of the ventricles flows fromthe lateral to the third and then

fourth ventricle, out throughforamina in the fourth, into thesubarachnoid space around the brainand spinal cord, and finally returns tothe blood by way of arachnoid villi.

5. CSF provides buoyancy, physicalprotection, and chemical stability forthe CNS.

6. The brain has a high demand forglucose and oxygen and thus receivesa copious blood supply.

7. The blood-brain barrier and blood-CSF barrier tightly regulate whatsubstances can escape the blood andreach the nervous tissue.

The Hindbrain and Midbrain (p. 524)1. The medulla oblongata is the most

caudal part of the brain, just insidethe foramen magnum. It conductssignals up and down the brainstemand between the brainstem andcerebellum, and contains nucleiinvolved in vasomotion, respiration,coughing, sneezing, salivation,swallowing, gagging, vomiting,gastrointestinal secretion, sweating,and muscles of tongue and headmovement. Cranial nerves IX throughXII arise from the medulla.

2. The pons is immediately rostral tothe medulla. It conducts signals upand down the brainstem and betweenthe brainstem and cerebellum, andcontains nuclei involved in sleep,hearing, equilibrium, taste, eyemovements, facial expression andsensation, respiration, swallowing,bladder control, and posture. Cranialnerve V arises from the pons, andnerves VI through VIII arise betweenthe pons and medulla.

3. The cerebellum is the largest part ofthe hindbrain. It is composed of twohemispheres joined by a vermis, andhas three pairs of cerebellarpeduncles that attach it to themedulla, pons, and midbrain andcarry signals between the brainstemand cerebellum.

4. Histologically, the cerebellumexhibits a fernlike pattern of white

matter called the arbor vitae, deepnuclei of gray matter embedded inthe white matter, and unusually largeneurons called Purkinje cells.

5. The cerebellum is concerned withmotor coordination and judging thepassage of time, and plays less-understood roles in awareness,judgment, memory, and emotion.

6. The midbrain is rostral to the pons. Itconducts signals up and down thebrainstem and between the brainstemand cerebellum, and contains nucleiinvolved in motor control, pain,visual attention, and auditoryreflexes. It gives rise to cranial nervesIII and IV.

7. The reticular formation is anelongated cluster of nuclei extendingthroughout the brainstem, includingsome of the nuclei alreadymentioned. It is involved in thecontrol of skeletal muscles, the visualgaze, breathing, swallowing, cardiacand vasomotor control, pain, sleep,consciousness, and sensoryawareness.

The Forebrain (p. 529)1. The forebrain consists of the

diencephalon and cerebrum.2. The diencephalon is composed of the

thalamus, hypothalamus, andepithalamus.

3. The thalamus receives sensory inputfrom the brainstem and first twocranial nerves, integrates sensorydata, and relays sensory informationto appropriate areas of the cerebrum.It is also involved in emotion,memory, arousal, and eyemovements.

4. The hypothalamus is inferior to thethalamus and forms the walls andfloor of the third ventricle. It is amajor homeostatic control center. Itsynthesizes some pituitary hormonesand controls the timing of pituitarysecretion, and it has nuclei concernedwith heart rate, blood pressure,gastrointestinal secretion andmotility, pupillary diameter,

Chapter Review

Review of Key Concepts

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440 Part Two Support and Movement

Testing Your Recall1. To make a muscle contract more

strongly, the nervous system canactivate more motor units. Thisprocess is calleda. recruitment.b. summation.c. incomplete tetanus.d. twitch.e. treppe.

2. The ______ is a depression in thesarcolemma that receives a motornerve ending.a. T tubuleb. terminal cisternac. sarcomered. motor end platee. synapse

3. Before a muscle fiber can contract,ATP must bind toa. a Z disc.b. the myosin head.c. tropomyosin.d. troponin.e. actin.

4. Before a muscle fiber can contract,Ca2� must bind toa. calsequestrin.b. the myosin head.c. tropomyosin.d. troponin.e. actin.

5. Skeletal muscle fibers have ______,whereas smooth muscle cells do not.a. T tubulesb. ACh receptorsc. thick myofilaments

d. thin myofilamentse. dense bodies

6. Smooth muscle cells have______,whereas skeletal muscle fibers do not.a. sarcoplasmic reticulumb. tropomyosinc. calmodulind. Z discse. myosin ATPase

7. ACh receptors are found mainly ina. synaptic vesicles.b. terminal cisternae.c. thick filaments.d. thin filaments.e. junctional folds.

8. Single-unit smooth muscle cells canstimulate each other because theyhavea. a latch-bridge.b. diffuse junctions.c. gap junctions.d. tight junctions.e. calcium pumps.

9. Warm-up exercises take advantage of______ to enable muscles to perform atpeak strength.a. the stress-relaxation responseb. the length-tension relationshipc. excitatory junction potentialsd. oxygen debte. treppe

10. Slow oxidative fibers have all of thefollowing excepta. an abundance of myoglobin.b. an abundance of glycogen.

c. high fatigue resistance.d. a red color.e. a high capacity to synthesize ATP

aerobically.

11. The minimum stimulus intensity thatwill make a muscle contract is called______.

12. A state of prolonged maximumcontraction is called ______.

13. Parts of the sarcoplasmic reticulumcalled ______ lie on each side of a Ttubule.

14. Thick myofilaments consist mainly ofthe protein ______.

15. The neurotransmitter that stimulatesskeletal muscle is ______.

16. Muscle contains an oxygen-bindingpigment called ______.

17. The ______ of skeletal muscle play thesame role as dense bodies in smoothmuscle.

18. In autonomic nerve fibers thatstimulate single-unit smooth muscle,the neurotransmitter is contained inswellings called ______.

19. A state of continual partial musclecontraction is called ______.

20. ______ is an end product of anaerobicfermentation that causes musclefatigue.

Answers in Appendix B

Answers in Appendix B

True or FalseDetermine which five of the followingstatements are false, and briefly explain why.

1. Each motor neuron supplies just onemuscle fiber.

2. To initiate muscle contraction,calcium ions must bind to the myosinheads.

3. Slow oxidative fibers are relativelyresistant to fatigue.

4. Thin filaments are found in both the Abands and I bands of striated muscle.

5. Thin filaments do not change lengthwhen a muscle contracts.

6. Smooth muscle lacks striationsbecause it does not have thick andthin myofilaments.

7. A muscle must contract to the pointof complete tetanus if it is to move a load.

8. If no ATP were available to a musclefiber, the excitation stage of muscleaction could not occur.

9. For the first 30 seconds of an intenseexercise, muscle gets most of itsenergy from lactic acid.

10. Cardiac and some smooth muscle areautorhythmic, but skeletal muscle is not.

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324 Part Two Support and Movement

True or FalseDetermine which five of the followingstatements are false, and briefly explain why.

1. More people get rheumatoid arthritisthan osteoarthritis.

2. A doctor who treats arthritis is calleda kinesiologist.

3. Synovial joints are also known assynarthroses.

4. There is no meniscus in the elbowjoint.

5. Reaching behind you to takesomething out of your hip pocketinvolves hyperextension of the shoulder.

6. The anterior cruciate ligamentnormally prevents hyperextension ofthe knee.

7. The femur is held tightly in theacetabulum mainly by the roundligament.

8. The knuckles are diarthroses.

9. Synovial fluid is secreted by thebursae.

10. Unlike most ligaments, theperiodontal ligaments do not attachone bone to another.

Testing Your Comprehension1. All second-class levers produce a

mechanical advantage greater than1.0 and all third-class levers producea mechanical advantage less than 1.0.Explain why.

2. Suppose a lever measures 17 cm fromeffort to fulcrum and 11 cm fromresistance to fulcrum. (a) Calculate itsmechanical advantage. (b) Would thislever produce more force, or less, thanthe force exerted on it? (c) Which ofthe three classes of levers could nothave these measurements? Explain.

3. In order of occurrence, list the jointactions (flexion, pronation, etc.) andthe joints where they would occur asyou (a) sit down at a table, (b) reachout and pick up an apple, (c) take abite, and (d) chew it. Assume thatyou start in anatomical position.

4. Suppose you were dissecting a cat orfetal pig with the task of findingexamples of each type of synovialjoint. Which type of human synovial

joint would not be found in either ofthose animals? For lack of that joint,what human joint actions wouldthose animals be unable to perform?

5. List the six types of synovial jointsand for each one, if possible,identify a joint in the upper limband a joint in the lower limb thatfalls into each category. Which ofthese six joints have no examples inthe lower limb?

Answers at the Online Learning Center

Answers to Figure Legend Questions9.5 The pubic symphysis consists of the

cartilaginous interpubic disc andthe adjacent parts of the two pubicbones.

9.6 Interphalangeal joints are notsubjected to a great deal ofcompression.

9.15 MA � 1.0. Shifting the fulcrum tothe left would increase the MA ofthis lever, while the lever wouldremain first-class.

9.18 The stylomandibular ligament isrelatively remote from the point

where the mandible and temporalbone meet.

9.24 It is the vertical band of tissueimmediately to the right of themedial meniscus.

http://www.mhhe.com/saladin3The Online Learning Center provides a wealth of information fully organized and integrated by chapter. You will find practice quizzes,interactive activities, labeling exercises, flashcards, and much more that will complement your learning and understanding of anatomyand physiology.

Answers in Appendix B

The "Testing Your Recall" questions and the "TestingYour Comprehension" questions provide and excellentopportunity for students to review the material in thechapter as a whole, testing not only recall ofinformation, but also the student’s ability to apply theinformation they recall.

- S. Kirkpatrick, Saint Francis University