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Human Reproductive Biology

THIRD EDITION Prelims-P088465 2/28/06 3:58 PM Page ii Prelims-P088465 2/28/06 3:58 PM Page iii

Human Reproductive Biology

THIRD EDITION

Richard E. Jones Professor of Biology Emeritus University of Colorado Boulder, Colorado

Kristin H. Lopez Department of Integrative Physiology University of Colorado Boulder, Colorado

AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Prelims-P088465 2/28/06 3:58 PM Page iv

Senior Acquisitions Editor: Nancy Maragioglio Project Manager: Philip Korn Associate Editor: Kelly Sonnack Marketing Manager: Trevor Daul Cover Design: Cate Barr Composition: Integra Software Pvt. Ltd. Cover Printer: Transcontinental Interglobe Interior Printer: Transcontinental Interglobe Academic Press is an imprint of Elsevier 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA 525 B Street, Suite 1900, San Diego, California 92101-4495, USA 84 Theobald’s Road, London WC1X 8RR, UK This book is printed on acid-free paper. Copyright © 2006, Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone: (44) 1865 843830, fax: (44) 1865 853333, E-mail: [email protected]. You may also complete your request on-line via the Elsevier homepage (http://elsevier.com), by selecting “Customer Support” and then “Obtaining Permissions.” Library of Congress Cataloging-in-Publication Data Jones, Richard E. (Richard Evan), 1940- Human reproductive biology / by Richard E. Jones. — 3rd ed. p. ; cm. Includes bibliographical references and index. ISBN-13: 978-0-12-088465-0 (hardcover : alk. paper) ISBN-10: 0-12-088465-8 (hardcover : alk. paper) 1. Human . 2. Sex. I. Title. [DNLM: 1. Reproduction—physiology. 2. Sexual Behavior. WQ 205 J78ha 2006] QP251.J636 2006 612.6—dc22 2005024432 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 13: 978-0-12-088465-0 ISBN 10: 0-12-088465-8

For all information on all Elsevier Academic Press publications visit our Web site at www.books.elsevier.com

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Working together to grow libraries in developing countries www.elsevier.com | www.bookaid.org | www.sabre.org Prelims-P088465 2/28/06 3:58 PM Page v

To my wife, Betty, and my four sons (Evan, Ryan, Peter, and Christopher) R.E.J.

To Tom and Jessica K.H.L. Prelims-P088465 2/28/06 3:58 PM Page vi Prelims-P088465 2/28/06 3:58 PM Page vii

Contents

Preface xvii Box 2: Kallmann’s Syndrome and the Embryological Origin and Migration of GnRH Cells 22 PART ONE Pineal Gland 23 Adult Female and Male Feedback Control of Gonadotropin Secretion 24 Reproductive Systems 1 Feedback Systems 24 Regulation of Gonadotropin Secretion by Negative Feedback 25 CHAPTER ONE Positive Feedback 26 , Brain Control of Prolactin Secretion 27 and 3 Chapter Summary 28 Further Reading 29 Introduction 3 Advanced Reading 29 Endocrine System 3 Science of Endocrinology 4 CHAPTER TWO 6 The Female Reproductive Receptors 6 System 31 Synthetic Hormones 9 The Pituitary Gland 10 Introduction 31 Hypothalamo–Neurohypophysial 31 Connection 10 Ovarian Gross Anatomy 31 Adenohypophysis 14 Ovarian Microanatomy 31 Hypothalamo–Adenohypophysial Connection 15 Stages of Follicular Growth 32 Releasing and Release-Inhibiting Follicular Atresia 36 Hormones 18 Ovarian Steroid Synthesis 36 Gonadotropin-Releasing Hormone 19 Hormonal Control of Follicular Growth Box 1: GnRH Analogs 20 and Steroidogenesis 39 The GnRH Pulse Generator and Maturation and Ovulation 40 Surge Center 21 Corpus Luteum 43

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Ovarian Disorders 44 CHAPTER THREE Ovarian Cysts 44 The Menstrual Cycle 73 Ovarian Cancer 45 Box 1: The Epidemic 46 Introduction 73 47 Reproductive Cycles in Mammals 73 48 Major Events in the Menstrual Cycle 75 Uterine Functional Anatomy 48 The Menstrual Cycle in Detail 76 Uterine Disorders 49 Menstrual Phase 76 Pelvic Infection 49 Follicular Phase 77 Cervical Cancer 49 Box 1: Why Women Menstruate 79 Cervical Cysts and Polyps 50 Luteal Phase 83 Endometrial Cancer 50 Variations in Length of Menstrual Endometriosis 51 Cycle Phases 85 Endometrial Polyps, Hyperplasia, Methods for Detecting Ovulation 85 and Fibroids 51 Home Methods 86 “Tipped” Uterus 52 Laboratory Methods 86 Prolapsed Uterus 52 Premenstrual Syndrome 87 53 Symptoms 87 Structure 53 Possible Causes and Treatments 87 The Vaginal Environment 53 Cyclic Changes in Mood and Skill Level 88 Female External Genitalia 54 Menstrual Difficulties 88 Mons Pubis 54 Dysmenorrhea 88 Labia Majora 54 Absence of Menstruation 89 Labia Minora 55 Box 2: Body Fat and Secondary Vestibule 55 Amenorrhea 89 Urethral Orifice 56 Menstrual Taboos 91 Clitoris 56 Chapter Summary 91 Mammary Glands 56 Further Reading 92 Functional Anatomy 56 Advanced Reading 93 Hormonal Control of Mammary Gland Function 58 CHAPTER FOUR Suckling 58 The Male 97 Noncancerous Breast Disorders 59 Breast Cancer 59 Introduction 97 Risk 59 Testes 97 Inherited Breast Cancer 60 Seminiferous Tubules 99 Noninherited Breast Cancer 61 and Spermiogenesis 99 Box 2: Xenoestrogens and Breast Cancer 62 Sertoli Cells 101 Detection 65 Testicular Interstitial Tissue 102 Treatment of Breast Cancer 66 Box 1: Are Male Sex Hormones 104 Chapter Summary 67 Hormonal Control of Testicular Function 105 Further Reading 68 Control of Gonadotropin Secretion Advanced Reading 70 in the Male 107 Prelims-P088465 2/28/06 3:58 PM Page ix

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Other Factors That Influence Testicular Box 1: Why the Y Chromosome? 130 Function 108 Sex-Linked Inheritance 132 Other Hormones 108 Development of the Reproductive System 133 Nutrition and Exercise 108 The Sexually Indifferent Stage 133 Chemicals, Radiation, and Infections 109 Gonadal Sex Differentiation 133 Anabolic Steroids 109 Ovarian Development 134 Testicular Cancer 109 Testicular Development 135 and Behavior 110 Testis-Determining Factor 137 Libido 110 Differentiation of Sex Accessory Ducts Aggression 110 and Glands 137 Count and Endocrine Disruptors 111 Differentiation of External Genitalia 138 Male Sex Accessory Ducts and Glands 112 Summary of Sexual Determination and Sex Accessory Ducts 112 Development 138 Epididymis 112 Disorders of Sexual Determination and Development 140 Vas Deferens 113 True Hermaphroditism 140 Urethra 113 Pseudohermaphroditism 140 Sex Accessory Glands 113 Box 2: Guevedoces 141 Seminal Vesicles 113 Chromosomal Errors and Sex Prostate Gland 114 Determination 144 Bulbourethral Glands 114 Other Problems in Sex Development 145 Prostate Disorders 114 Reproductive System in the Newborn 145 Hormonal Control of Sex Accessory Chapter Summary 146 Structures 117 Further Reading 147 Penis 117 Advanced Reading 147 Scrotum 118 Box 2: Why a Scrotum? 119 CHAPTER SIX Chapter Summary 121 149 Further Reading 121 Advanced Reading 122 Introduction 149 Puberty and Its Timing 149 The Pubertal Process 149 PART TWO Pubertal Changes in Females 149 Sexual Differentiation Pubertal Changes in Males 151 and Development 125 Classification of Pubertal Changes 153 Gonadal Changes from Birth to Puberty 156 Ovarian Changes 156 CHAPTER FIVE Testicular Changes 157 Sexual Differentiation 127 Cryptorchid Testes 157 Hormone Levels from Birth to Puberty 158 Introduction 127 Hormones in Females 160 Chromosomal Sex 127 Menarche and First Ovulation 160 X Chromosome 127 Estrogens 160 Y Chromosome 129 Androgens 160 Prelims-P088465 2/28/06 3:58 PM Page x

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Hormone Levels in Males 160 PART THREE Gonadotropins and Androgens 160 Procreation 191 Estrogens 161 Androgens and Acne 161 What Mechanisms Cause Puberty? 161 CHAPTER EIGHT Environmental Factors and Puberty 163 The Human Sexual Response 193 Nutrition 164 Day Length and Season 165 Introduction 193 Stressors 165 Sex Roles 193 Box 1: Early Childhood Stress and Sexual Maturation 166 Factors Influencing Sex Roles 193 Environmental Pollutants 167 Gender Identity 193 Climate and Altitude 168 Nature or Nurture 194 Inheritance and Age of Puberty 168 Sexual Arousal 194 Box 2: Puberty Genes 168 Cultural Influence and Individual Variation 194 Puberty and Psychosocial Adjustment 170 Erotic Stimuli 195 Chapter Summary 171 Erogenous Zones 195 Further Reading 171 Proceptive Behavior 195 Advanced Reading 172 The Sexual Response Cycle 196 196 CHAPTER SEVEN The Female Sexual Response Cycle Excitement Phase 197 Reproductive Aging 175 Plateau Phase 198 Orgasmic Phase 198 Introduction 175 Resolution Phase 200 Menopause 175 Individual Variation 201 Timing of Menopause 176 The Male Sexual Response Cycle 201 Female Reproductive Age 176 Excitement Phase 201 Box 1: Egg Aging 177 Plateau Phase 203 Perimenopause 179 Orgasmic Phase 204 Premature Menopause 179 Resolution Phase 205 Symptoms of Menopause 179 Why Did Orgasm Evolve? 205 Endocrine Changes during Menopause 180 Coitus (Sexual Intercourse) 205 Chance of Pregnancy 182 Hormones and Sexual Behavior 207 Box 2: The Evolution of Menopause in Humans 183 Hormones and Male Sexual Behavior 207 Osteoporosis and Other Postmenopausal Box 1: Human Pheromones and Disorders 184 the Vomeronasal Organ 208 Treatments for Menopause: Benefits Hormones and Female Sexual Behavior 209 and Risks 185 Box 2: Human Mating Systems 210 Andropause 187 Homosexuality 213 Testicular Function in Old Age 187 Myths 215 Chapter Summary 188 Sexual Activity and Response 215 Further Reading 189 Patterns of Sexual Behavior 216 Advanced Reading 189 Psychoanalytic Theory 216 Prelims-P088465 2/28/06 3:58 PM Page xi

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Learning Theory 216 Sperm Passage through the Zona Hormones 217 Pellucida 240 Genetic Basis of Homosexuality 217 Sperm Attachment to the Egg Plasma Membrane 242 Conclusions 218 The Cortical Reaction 242 Homophobia 218 Completion of the Second Meiotic Treatment 219 Division 242 Transsexualism 219 Formation and Fusion of Sperm Sexual Dysfunction 220 and Egg Pronuclei 243 Vaginismus 220 Box 2: Sperm Hitchhikers 244 Dyspareunia 221 Chemical Inhibition of Fertilization 246 Premature Ejaculation 221 Sex Ratios 246 Ejaculatory Incompetence 221 Sex Preselection 247 Erectile Dysfunction 221 Multiple Embryos 248 Orgasmic Dysfunction 222 Parthenogenesis 248 Drugs and Human Sexual Chromosomal Aberrations 248 Behavior 223 Chapter Summary 251 Therapeutic Drugs 224 Further Reading 251 Nontherapeutic Drugs 224 Advanced Reading 252 Chapter Summary 226 Further Reading 227 Advanced Reading 228 CHAPTER TEN Pregnancy 253 CHAPTER NINE Transport and Introduction 253 What Is Pregnancy? 253 Fertilization 231 Signs of Pregnancy 254 Pregnancy Tests 255 Introduction 231 What to Do If You Are Pregnant 255 Semen Release 231 The Process of Pregnancy 256 Contents of Seminal Plasma 232 Implantation 256 Sperm Number and Structure 233 Box 1: Trading of Cells between Fetus Sperm Transport and Maturation in and Mom during Pregnancy 261 the Female Reproductive Tract 234 Early Embryonic Development 263 Vaginal Sperm 234 Extraembryonic Membranes 263 Cervical Sperm 235 The Placenta 265 Uterine Sperm 235 Box 2: Maternal and Paternal Genetic Transport of the Sperm and Ovum in Imprinting 268 the 236 Twin Pregnancies 270 Sperm Capacitation and Activation 237 Embryonic and Fetal Development 271 When Can Fertilization Occur? 237 The Embryonic Period 271 Box 1: Does the Human Egg Court Sperm? 238 The Fetal Period 273 The Process of Fertilization 239 Digestive/Urinary Systems 275 Sperm Passage through the Cumulus Circulatory System 275 Oophorus 239 Nervous System 275 Prelims-P088465 2/28/06 3:58 PM Page xii

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Endocrine System 277 The Birth Process 305 Fetal Disorders 277 Stage 1: Cervical Effacement Genetic and Chromosomal Disorders 277 and Dilation 305 Rhesus Disease 277 Stage 2: Expulsion of the Fetus 310 Teratogens, Mutagens, and Other Stage 3: Expulsion of the Placenta 311 Agents That Damage the Fetus 278 Premature Births 312 Viruses and Bacteria 278 Multiple Births 313 Environmental Pollutants 279 Difficult Fetal Positions 314 Drugs, Alcohol, and Tobacco 279 Handling Difficult Births 315 Box 3: The Adaptive Value of Morning Forceps Delivery 315 Sickness 281 Vacuum Extraction 315 Radiation 283 Cesarean Delivery 316 High Altitude 283 Use of Medications during Labor 317 Fetal Evaluation 283 Natural Birthing Methods 319 The Pregnant Woman 285 Box 2: Why Is Human Birth So Maternal Nutrition 285 Difficult? 320 Physiological Changes during Pregnancy 286 Chapter Summary 322 The Endocrinology of Pregnancy 286 Further Reading 323 Maternal Complications of Pregnancy 289 Advanced Reading 324 Toxemia 289 Diabetes Mellitus 290 CHAPTER TWELVE Ectopic Pregnancies 290 The Neonate and the New Hydatidiform Moles 291 Parents 325 Septic Pregnancy 291 Hemorrhage 291 Introduction 325 Miscarriage 291 Treatment of the Newborn 325 Sex during Pregnancy 292 Apgar Score 325 Chances for a Successful Pregnancy 292 Leboyer Method 326 Chapter Summary 293 Circumcision 326 Further Reading 294 Adaptations of the Newborn 327 Advanced Reading 295 The Respiratory System 327 The Circulatory System 328 CHAPTER ELEVEN The Digestive Tract 328 Labor and Birth 297 Thermoregulation 329 The Nervous System and Behavior 329 Introduction 297 What a Newborn Looks Like 330 Time of Birth 297 Disorders of the Newborn 331 Hormones and Birth 300 Box 1: Back to Sleep 332 Delayed Birth in Sheep 300 Birth Weight and Adult Disease 334 Hormonal Initiation of Human Birth 301 Condition of the New Mother 335 Box 1: The Placental Clock 301 Physical Changes 335 Induced Labor 304 Psychological Changes 335 Preparation for Labor 305 Breast-Feeding 336 Prelims-P088465 2/28/06 3:58 PM Page xiii

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Postpartum Endocrine Changes Population Growth in Underdeveloped and Lactation 336 Countries 363 Box 2: The Duration of Overall View of Human Population Breast-Feeding 339 Growth 365 Advantages and Disadvantages Effects of Overpopulation 365 of Breast- and Bottle-Feeding 341 Illiteracy 365 Chapter Summary 343 Food Production and Hunger 366 Further Reading 345 Natural Resources and Energy 366 Advanced Reading 346 Pollution and Environmental Illness 367 Crowding and Stress 367 Quality of Life 368 PART FOUR Will Science and Technology Save Us? 368 and its Control 349 Family Planning and Population Control 369 Family Planning Programs 369 Barriers to Family Planning 370 CHAPTER THIRTEEN Cultural Barriers 370 Human Population Growth Religious Barriers 371 and Family Planning 351 Other Barriers 371 Family Planning in the United States 372 Introduction 351 Individual Freedom and Family Planning 374 The Biology of Population Growth 351 Box 2: Government-Enforced Population Basic Principles of Population Control in China 374 Biology 351 Chapter Summary 376 Birth Rate 351 Further Reading 377 Death Rate 352 Advanced Reading 378 Emigration and Immigration 352 Population Growth Rate 352 CHAPTER FOURTEEN Reproductive Potential 353 Contraception 379 Biotic Potential 353 Environmental Resistance 353 Introduction 379 Population Crashes 354 Combination Pill 381 Doubling Time 355 Ingredients 382 Human Population Growth 356 How the Combination Pill Works 382 The Prediction of Thomas Malthus 356 Use of the Combination Pill 382 Human Population Growth on Earth 356 Failure Rate 383 Age Distribution 358 Side Effects 383 Birth Rate, Death Rate, and Fertility Rate 358 Mild Side Effects 383 Box 1: World Contraceptive Use Serious Side Effects 384 and Fertility Rates 361 Beneficial Side Effects 385 Life Expectancy 362 Costs and Benefits 385 Population Growth in Developed Minipill 389 Countries 362 Box 1: Where Is the Male Birth U.S. Population Growth 362 Control Pill? 389 Prelims-P088465 2/28/06 3:58 PM Page xiv

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Intradermal Progestogen Implants 391 First Trimester-Induced Abortions 423 Injectable Hormones 392 Vacuum Aspiration 424 Transdermal Hormone Delivery 392 Dilation and Curettage 426 Emergency Contraception 393 Prostaglandins 427 Intrauterine Devices 393 Medication Abortion: Mifepristone, Spermicides 395 Methotrexate, and Misoprostol 427 Box 2: Future Contraceptive Methods 396 Box 2: The Early Abortion Pill in the United States 428 Diaphragm 398 Second Trimester Induced Abortions 429 Cervical Cap 399 Why a Second Trimester Abortion? 429 Sponge Contraceptive 399 Intraamnionic Saline 430 Male and Female Condoms 400 Prostaglandin Injections 430 Male Condom 400 Dilation and Evacuation 431 Female Condom 400 Dilation and Extraction 431 Coitus Interruptus 401 Third Trimester-Induced Abortions 431 Coitus Reservatus and Coitus Obstructus 401 Folk Abortifacients 432 Natural Family Planning 402 Safety and Consequences of Induced Calendar Method 402 Abortion 432 Basal Body Temperature Method 402 Chapter Summary 433 Cervical Mucus Method 403 Further Reading 434 Sympto-Thermal Method 403 Advanced Reading 434 Is Breast-Feeding a Contraceptive Measure? 403 Surgical Sterilization 403 CHAPTER SIXTEEN Tubal Sterilization 404 Infertility 437 Hysterectomy 407 Vasectomy 407 Introduction 437 Psychology of Contraceptive Avoidance 409 Seeking Medical Help for Infertility 437 Choosing a Contraceptive 410 Female Infertility 438 Chapter Summary 410 Failure to Ovulate 438 Further Reading 411 Tubal Blockage 439 Advanced Reading 413 Absence of Implantation 440 Reduced Sperm Transport or Antibodies CHAPTER FIFTEEN to Sperm 440 Induced Abortion 417 Box 1: Seasonal Changes in the Ability to Conceive 441 Pregnancy Loss (Miscarriage) 442 Introduction 417 Male Infertility 443 Induced Abortion in the United States 418 Low Sperm Count 443 History of Abortion Legislation in the United States 418 Sperm Transport 444 Present-Day Abortion Statistics in Environmental Factors 444 the United States 419 Assisted Reproductive Techniques (ART) 445 Why Women Have Abortions 420 Gamete Storage and Artificial Box 1: The History and Ethics Insemination (AI) 445 of Induced Abortion 422 In Vitro Fertilization (IVF) 447 Prelims-P088465 2/28/06 3:58 PM Page xv

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Ovarian Stimulation and Egg Conclusion 485 Retrieval 447 Chapter Summary 485 Fertilization and Embryo Transfer 447 Further Reading 486 Risks of IVF 449 Advanced Reading 487 Box 2: Costs of Assisted Reproductive Technologies 450 Preimplantation Genetic Diagnosis CHAPTER EIGHTEEN (PGD) 452 Sexually Transmitted Diseases 491 Egg Donation 453 Gamete or Intrafallopian Introduction 491 Transfer 453 Bacteria and Viruses 491 Surrogate Mothers and Gestational Carriers 454 Gonorrhea 493 Cloning and Ethical Issues in Assisted Cause of the Gonorrhea Epidemic 493 Reproduction 454 Cause of Gonorrhea 493 Adoption 457 Transmission 494 Chapter Summary 457 Symptoms in Females 494 Further Reading 458 Complications in Females 494 Advanced Reading 459 Pregnancy and Gonorrhea 495 Symptoms in Males 495 Diagnosis 495 Treatment 495 FIVE PART Syphilis 496 Special Topics in Human Theoretical Origins 496 461 Reproductive Biology Columbian Theory 496 Evolutionary Theory 497 Syphilis as Distinct from CHAPTER SEVENTEEN Gonorrhea 497 Brain Sex 463 Transmission 497 Stages of the Disease 497 Introduction 463 Primary Stage 497 Biological Causes of Brain Sex Differences 463 Secondary Stage 498 Sex Differences in Neonatal Behavior 467 Latent Stage 498 Sex Differences in Childhood Behavior 467 Tertiary Stage 498 Sex Differences in Adult Cognition Congenital Syphilis 498 and Motor Skills 468 Diagnosis 499 Box 1: Evolution of Sex Differences Treatment 499 in Problem-Solving Skills 473 Chlamydia 499 Brain Sex Differences in the “Surge Center” 476 Genital Herpes 500 Brain Sex and Human Sexual Behavior 477 Cause 501 Sexual Orientation 477 Symptoms 501 Brain Sex and Gender Identity 482 Diagnosis 502 Sex Differences in Aggression 483 Treatment 502 Box 2: The Meaning of Genital Warts 502 Brain Measurements 483 Trichomoniasis 503 Prelims-P088465 2/28/06 3:58 PM Page xvi

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Viral Hepatitis B 504 Some General Aspects of Venereal Disease Pediculosis Pubis 504 Infections 525 Scabies 505 Vulvitis 525 Lymphogranuloma Venereum 505 Vaginitis 525 Chancroid 505 Urethritis and Cystitis 527 Molluscum Contagiosum 506 Cervicitis 527 Granuloma Inguinale 506 Pelvic Inflammatory Disease 527 Acquired Immunodeficiency Syndrome Prostatitis 528 (AIDS) 506 Psychological Aspects of Sexually Statistics 506 Transmitted Disease 528 Box 1: Origins of the HIV Viruses 510 Preventing Sexually Transmitted Disease 529 Transmission 512 Chapter Summary 529 Who Is Most Susceptible to HIV Further Reading 530 Infection? 514 Advanced Reading 531 Life Cycle of the HIV Virus 515 Symptoms of HIV Disease and AIDS 516 Glossary 533 Long-Term HIV Survivors 518 Illustration and Table Credits 581 Treatments of AIDS 519 Index 589 Box 2: Attacking the HIV Virus 522 Precautions Against HIV Transmission 524 Prelims-P088465 2/28/06 3:58 PM Page xvii

Preface

A New Contraceptive in the Works! Hormone Replacement Therapy for Menopause Increases the Risk of Heart Disease! Anabolic Steroids Linked to Psychiatric Disorders! Headlines such as these appear in the media almost every day as advances in the field of human reproductive biology are made. Reproductive biology and biomedicine are of primary concern to people of all ages. One goal of this third edition of Human Reproductive Biology is to give col- lege students a solid foundation in understanding the human reproductive system so that they can critically evaluate and interpret new findings as they prepare for careers in reproductive biology and medicine, or for their own personal interest. Scientific research in this area is proceeding with great rapidity. The time between publication of the second edition of Human Reproductive Biology and the present (2006) has been loaded with new research findings that have pro- found influence on our basic understanding in this scientific discipline. In turn, advances in basic biology has a major impact on the practice of reproductive medicine. So the third edition is “pregnant” with new information and has been updated throughout. Our goal is to give you the latest available findings. In addition to adding new and exciting facts, this edition has been changed in ways that add to the teaching value of the book. Eighteen new Highlight Boxes,” presenting especially intriguing topics or areas of special interest, have been added. For the first time, the figures are in full color to help the student interpret and understand the structure and function of the reproductive system. A new chapter on Reproductive Aging has been added. The references at the end of each chapter have been expanded to help the student research a topic for writing term papers or to follow up on a topic of interest in the literature. A ded- icated student in a class using this text should know and understand more about than about 95% of adults! This book will help prepare stu- dents who are considering careers as health care professionals or biomedical researchers. The students will also derive benefit in their personal lives, regard- less of career choice. It is our experience that a student would need at least one year of college general biology to gain the greatest benefit from taking a course using Human Reproductive Biology. We have chosen illustrations and tables that offer clear examples of phe- nomena discussed in the text. Furthermore, we explain each figure fully in the legend, thus saving the reader from searching the text for clarification. A list of illustration and table credits appears at the back of the book. Within the text, key terms are italicized the first time they are used and are also defined in the Glossary. We are, by profession, reproductive biologists and endocrinologists, and we have used our training and knowledge to the best of our abilities to make this

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book as scientifically accurate and up-to-date as possible. Although we are not medical doctors, we have attempted to present valid medical information. However, we do not take legal responsibility for any medical information or advice in this book; that is, the readers of this book use medical information and advice contained herein at their own risk, and should always check with their physicians regarding any health or medical problems or treatments. We wish to note that it is our intention to provide new Highlight Boxes for readers, particularly course instructors and students. Any updates, as warranted by major developments in the field, will be made available on the publisher’s Internet site, under the book’s dedicated Web pages (http://books.elsevier.com). We would like to extend our appreciation to the staff at Academic Press/Elsevier for their help and enthusiastic support in the production of this third edition, especially Nancy Maragioglio, Kelly Sonnack, and Philip Korn. A special warm thanks to our colleague and friend Dr. Leif Saul, who used his artistic skill and scientific knowledge to provide us with the many new color figures in this edition. R.E.J. K.H.L.