Mader: Understanding ② The McG ysiology, Fifth Edition Preface We cannot teach people anything; we can only help them discover it Mader texts are well known for their pedagogical features and those for this text are described in the guided Tour on Over the years, it has been my privilege to meet many of the pages xv-xXx. Also, as with other Mader texts, the illustra adopters of my texts at various meetings around the coun- tions are excellent try. At one such meeting, I met a professor who told me that William I. Burke, of Madison Area Technical College, states, he and his colleagues were using my book, Human biology This text has some very good art. It is well labeled and has for an anatomy and physiology course because they wanted a good color scheme that helps it stand out. The inclusion of to use a Mader text. When I returned home, i pondered over the many tables and charts is also an excellent learning tool this and decided that I would write an anatomy and physi- ology text so that professors teaching that course would have a more appropriate Mader textbook. Thus, began the My vision for Understanding Human Anatomy and Physiology development of this text, Understanding Human Anatomy encompasses three goals. I want students to develop a and Physiology, which is now in its fifth edition. working knowledge of (1) anatomy and physiology that is based on conceptual understanding rather than rote mem dience--from those in traditional allied health fields to oth. ory;(2)medical terminology that will increase the stu- ers who are a bit removed from traditional endeavors. The dent's confidence in their chosen field; and ( 3)clinical ap book should be clear and direct, with objectives that are plications to broaden their horizons beyond the core achievable by students who have no previous science back. principles ound and even by those who are science shy. This goal was Dr Philip Swartz, of Houston Community College systen writes, Each chapter includes salient clinical concepts that Diane Kelly, of Broome Community College, writes, " I think will be fascinating to the reader and enhance his or her the text is very readable, clear, and user friendly. The art is understanding of the material being presented wonderful complement to the author's writing together, the formation is clearly presented. About the Author Sylvia S Mader In her 20-year career with McGraw-Hill, Dr Mader has written an impressive collection of textbooks. Aside from Understanding Human Anatomy and Physiology, now in its fifth edition, Dr. Mader has written Biology, eighth edition; Human Biology eighth edi- tion,and Inquiry into Life, tenth edition, through which Dr. Mader has successfully helped innumerable students learn biology as well as human anatomy and physiology. Dr. Mader's interest in anatomy and physiology began when she took courses at the Medical School of St Andrews Uni versity, in Scotland, during her junior year abroad. As a fledgling faculty member, she was called upon to teach a variety of courses, among them was human anatomy and physiology. As a textbook writer she discovered that the teaching and learning techniques she so successfully used in the classroom were appropriate for her biology texts and then later for her anatomy and physiology text. Dr. Mader's direct writing style and carefully constructed pedagogy provide students with an opportunity to learn the basics of biology and
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 We cannot teach people anything; we can only help them discover it within themselves. Galileo Galilei Over the years, it has been my privilege to meet many of the adopters of my texts at various meetings around the country. At one such meeting, I met a professor who told me that he and his colleagues were using my book, Human Biology for an anatomy and physiology course because they wanted to use a Mader text. When I returned home, I pondered over this and decided that I would write an anatomy and physiology text so that professors teaching that course would have a more appropriate Mader textbook. Thus, began the development of this text, Understanding Human Anatomy and Physiology, which is now in its fifth edition. I wanted to write a text that would appeal to a wide audience_from those in traditional allied health fields to others who are a bit removed from traditional endeavors. The book should be clear and direct, with objectives that are achievable by students who have no previous science background and even by those who are science shy. This goal was reached. Diane Kelly, of Broome Community College, writes, “I think the text is very readable, clear, and user friendly. The art is a wonderful complement to the author’s writing; together, the information is clearly presented.” Mader texts are well known for their pedagogical features, and those for this text are described in the Guided Tour on pages xv-xx. Also, as with other Mader texts, the illustrations are excellent. William J. Burke, of Madison Area Technical College, states, “This text has some very good art. It is well labeled and has a good color scheme that helps it stand out. The inclusion of the many tables and charts is also an excellent learning tool for the students.” My vision for Understanding Human Anatomy and Physiology encompasses three goals. I want students to develop a working knowledge of (1) anatomy and physiology that is based on conceptual understanding rather than rote memory; (2) medical terminology that will increase the student’s confidence in their chosen field; and (3) clinical applications to broaden their horizons beyond the core principles. Dr. Philip Swartz, of Houston Community College system, writes, “Each chapter includes salient clinical concepts that will be fascinating to the reader and enhance his or her understanding of the material being presented.” viii About the Author Sylvia S. Mader In her 20-year career with McGraw-Hill, Dr. Mader has written an impressive collection of textbooks. Aside from Understanding Human Anatomy and Physiology, now in its fifth edition, Dr. Mader has written Biology, eighth edition; Human Biology, eighth edition, and Inquiry into Life, tenth edition, through which Dr. Mader has successfully helped innumerable students learn biology as well as human anatomy and physiology. Dr. Mader’s interest in anatomy and physiology began when she took courses at the Medical School of St. Andrews University, in Scotland, during her junior year abroad. As a fledgling faculty member, she was called upon to teach a variety of courses, among them was human anatomy and physiology. As a textbook writer she discovered that the teaching and learning techniques she so successfully used in the classroom were appropriate for her biology texts and then later for her anatomy and physiology text. Dr. Mader’s direct writing style and carefully constructed pedagogy provide students with an opportunity to learn the basics of biology and anatomy and physiology
Mader: Understanding ② The McG ysiology, Fifth Edition What's New to This edition? that are now experimental but promise to be particularly help- ful in the future. For example, a What's New box in the first chapter tells about organs made in the laboratory that are now New Design and Illustrations eing transplanted into patients. The What's New reading in A new, colorful design and revised illustrations enhance the Chapter 8 describes a "pacemaker"for Parkinson diseas features of Understanding Human Anatomy and Physiology, fifth Chapter Openers on micrographs, X-rays, and MRI images open Organization the chapters for a closer look into the wonders of the human This edition follows the same general sequence as the earlier body. The integrated outline has been retained with the addi- editions. It is divided into five parts of a numbering system for each major concept found in the chapter, including the summary. Part I,"Human Organization, provides understanding of how the body is organized and the terminology used to refer to various body parts and their Visual Focus locations. Chapters 2 through 4 describe the chemistry Visual Focus illustrations are included in several chapters of the cell, cell structure and function and the tissues With the addition of boxed statements, these in-depth illustra- and membranes of the body tions, which contain several art pieces, cover a process from Part IL, "Support, Movement, and Protection, " includes start to finish. For example, Figure 7. 3 outlines contraction of the integumentary system in addition to the skeletal and a muscle from the macroscopic to the microscopic perspective muscular systems Part Ill, "Integration and Coordination, "explains that the nervous and endocrine systems are vitally important Chapter End Matter This edition includes updated Selected New Terms, Sum homeostasis, while the sensory system provides the maries, Study Questions, Objective Questions, Medical Ter- nervous system with information about the internal an minology Reinforcement Exercises, and Website Links to the external environment cardiovascular, lymphatic, respiratory, digestive, and e Part IV, "Maintenance of the body, " describes how th urinary systems contribute to the maintenance of Objective Questions homeostasis Labeling exercises have been added to chapters 8, 11, 14, and Part V, Reproduction and Development, concerns the 18 to reinforce the concepts of the chapter. reproductive systems, development, and the basics of human genetics, including modern advances Chapter Updates and Additions Homeostasis The theme of homeostasis is strengthened in this edition. As Chapter 1: Organization of the Body before, Chapter I describes how various feedback mecha- New illustrations, tables, and a reading titled"Organs for nisms work to maintain the internal environment within a Transplantintroduce the student to the human body. The narrow range. New to this edition, each systems chapter ends discussion of negative feedback now includes temperature with a major section on homeostasis to accompany the"Hu- control as an example and also includes a discussion of posi- man Systems Work Together"illustration. This section de- tive feedback, as requested by reviewers scribes how the system under discussion, with the help of the other systems, maintains homeostasis Chapter 2: Chemistry of Life New Readings This chapter has been reorganized and rewritten to help stu- dents understand fundamental chemistry concepts. Carbohy Understanding Human Anatomy and Physiology, fifth edition, has drates, lipids, proteins, and nucleic acids each have their own two types of readings. Previously, the book had two types of major section readings called Medical Focus and MedAlert. In this edition, the read ings are Medical Focus and what's New Some of the Chapter 3: Cell Structure and Function moved, and most of the others have been revised. The What's Cellular Organization, Crossing the Plasma Membrane, and New readings, which are new to this edition, tell of treatments The Cell Cycle are clearly defined as chapter sections. Tables Preface ix
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 Preface ix What’s New to This Edition? New Design and Illustrations A new, colorful design and revised illustrations enhance the features of Understanding Human Anatomy and Physiology, fifth edition. Organization This edition follows the same general sequence as the earlier editions. It is divided into five parts: Part I, “Human Organization,” provides an understanding of how the body is organized and the terminology used to refer to various body parts and their locations. Chapters 2 through 4 describe the chemistry of the cell, cell structure and function, and the tissues and membranes of the body. Part II, “Support, Movement, and Protection,” includes the integumentary system in addition to the skeletal and muscular systems. Part III, “Integration and Coordination,” explains that the nervous and endocrine systems are vitally important to the coordination of body systems, and therefore homeostasis, while the sensory system provides the nervous system with information about the internal and external environments. Part IV, “Maintenance of the Body,” describes how the cardiovascular, lymphatic, respiratory, digestive, and urinary systems contribute to the maintenance of homeostasis. Part V, “Reproduction and Development,” concerns the reproductive systems, development, and the basics of human genetics, including modern advances. Homeostasis The theme of homeostasis is strengthened in this edition. As before, Chapter 1 describes how various feedback mechanisms work to maintain the internal environment within a narrow range. New to this edition, each systems chapter ends with a major section on homeostasis to accompany the “Human Systems Work Together” illustration. This section describes how the system under discussion, with the help of the other systems, maintains homeostasis. New Readings Understanding Human Anatomy and Physiology, fifth edition, has two types of readings. Previously, the book had two types of readings called Medical Focus and MedAlert. In this edition, the readings are Medical Focus and What’s New. Some of the Medical Focus readings from the fourth edition have been removed, and most of the others have been revised. The What’s New readings, which are new to this edition, tell of treatments that are now experimental but promise to be particularly helpful in the future. For example, a What’s New box in the first chapter tells about organs made in the laboratory that are now being transplanted into patients. The What’s New reading in Chapter 8 describes a “pacemaker” for Parkinson disease. Chapter Openers Scanning electron micrographs, X-rays, and MRI images open the chapters for a closer look into the wonders of the human body. The integrated outline has been retained with the addition of a numbering system for each major concept found in the chapter, including the summary. Visual Focus Visual Focus illustrations are included in several chapters. With the addition of boxed statements, these in-depth illustrations, which contain several art pieces, cover a process from start to finish. For example, Figure 7.3 outlines contraction of a muscle from the macroscopic to the microscopic perspective. Chapter End Matter This edition includes updated Selected New Terms, Summaries, Study Questions, Objective Questions, Medical Terminology Reinforcement Exercises, and Website Links to the Online Learning Center. Objective Questions Labeling exercises have been added to chapters 8, 11, 14, and 18 to reinforce the concepts of the chapter. Chapter Updates and Additions Chapter 1: Organization of the Body New illustrations, tables, and a reading titled “Organs for Transplant” introduce the student to the human body. The discussion of negative feedback now includes temperature control as an example and also includes a discussion of positive feedback, as requested by reviewers. Chapter 2: Chemistry of Life This chapter has been reorganized and rewritten to help students understand fundamental chemistry concepts. Carbohydrates, lipids, proteins, and nucleic acids each have their own major section. Chapter 3: Cell Structure and Function Cellular Organization, Crossing the Plasma Membrane, and The Cell Cycle are clearly defined as chapter sections. Tables
Mader: Understanding ② The McG ysiology, Fifth Edition 3.1, 3.2, and all art are new to this edition. The Medical Focus Chapter 10: The Endocrine System reading," Dehydration and Water Intoxication"is also new to An overview of the endocrine glands now precedes an im- proved discussion of each gland. A new illustration shows how the adrenal medulla and the adrenal cortex are in- Chapter 4: Body Tissues and Membranes volved in short-term and long-term stress, respectively f tissue now has its own major section. In addition Other new illustrations pertain to regulation of blood cal- to body membranes, connections between cells and different cium, regulation of blood pressure, Addison disease, and pes of glands are discussed in respective sections. Art and ta- Cushing syndrome. The chapter also includes a discussion les have been revised for this chapter. of chemical signals in general and how hormones affect cel lular metabolism Chapter 5: The Integumentary System Chapter 11: Blood Section 5.5. Homeostasis is new to this edition. It shows how the various functions of the skin assist the body in maintain- A detailed description of the composition and function of ing homeostasis. Also discussed are hyperthermia an pothermia, which occur when homeostasis has been over- come. The section is accompanied by an updated Human centers around hemostasis, including coagulation. The trans- Systems Work Together illustration port function of blood is illustrated by considering capillary exchange. The last section of the chapter, Blood Typing and Transfusions, is supported by new art that clearly illustrates Chapter 6: The Skeletal System blood types and agglutination New illustrations, each of which is on the or a facing page to its reference, much improve this chapter. More infor- or. Chapter 12: The Cardiovascular System mation is given about each bone and joint discussed. The An overview of the cardiovascular system, supported by an chapter ends with a review of the many ways the skeletal sys- illustration, offers a much-improved introduction to the tem helps maintain homeostasis hapter, which has been reorgal e parts: the anatomy of the heart, the physiology of the heart, the Chapter7: The Muscular System anatomy of blood vessels, the physiology of circulation The first two illustrations in this chapter are new: The first and peripheral resistance improves tle of cardiac output shows the three types of muscles, and the second describes the chapter connective tissue coverings within and around a skeletal mus- dle. Instructors and students will appreciate the new in-depth discussion of the sources of energy for muscle contraction, which is also accompanied by a new illustration ester 13: The Lymphatic System and Body As requested by reviewers, the lymphatic organs are now Chapter 8: The Nervous System divided into those that are primary and those that are sec ondary. The discussion of specifi c immunity This chapter was rewritten In particular, the discussion of the proved by new illustrations depicting the action of B cells cerebrum has been expanded to include not only the various and T cells. A new reading on emerging diseases modernizes lobes but also the areas within these lobes. The somatic sys- the chapter tem of the peripheral nervous system is now clearly defined, nd the al reflex has been moved to this section lustrations support improved discussions of all aspects of the Chapter 14: The Respiratory System nervous system An improved Table 14. 1, which includes a description of the respiratory organs, adds to the discussion of the respiratory Chapter The Sensory System system. The respiratory membrane is better described and is ccompanied by a new illustration. The section entitled Types of senses, rather than types of receptors, are now used to Mechanism of Breathing is better organized so that regulation organize this chapter. The discussions of the anatomy and of breathing rates now has its own subsection. Following physiology of the eye and ear are better organized, with an em- reviewers'suggestions, the chapter is more student friendly phasis on how information regarding vision and sound is gen- because gas exchange and transport no longer require a erated and transmitted to the brain. The sense of equilibrium knowledge of partial pressures. All readings are new or exten is now divided into rotational and gravitational equilibrium. sively revised X Preface
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 3.1, 3.2, and all art are new to this edition. The Medical Focus reading, “Dehydration and Water Intoxication” is also new to this edition. Chapter 4: Body Tissues and Membranes Each type of tissue now has its own major section. In addition to body membranes, connections between cells and different types of glands are discussed in respective sections. Art and tables have been revised for this chapter. Chapter 5: The Integumentary System Section 5.5. Homeostasis is new to this edition. It shows how the various functions of the skin assist the body in maintaining homeostasis. Also discussed are hyperthermia and hypothermia, which occur when homeostasis has been overcome. The section is accompanied by an updated Human Systems Work Together illustration. Chapter 6: The Skeletal System New illustrations, each of which is on the same or a facing page to its reference, much improve this chapter. More information is given about each bone and joint discussed. The chapter ends with a review of the many ways the skeletal system helps maintain homeostasis. Chapter 7: The Muscular System The first two illustrations in this chapter are new: The first shows the three types of muscles, and the second describes the connective tissue coverings within and around a skeletal muscle. Instructors and students will appreciate the new in-depth discussion of the sources of energy for muscle contraction, which is also accompanied by a new illustration. Chapter 8: The Nervous System This chapter was rewritten. In particular, the discussion of the cerebrum has been expanded to include not only the various lobes but also the areas within these lobes. The somatic system of the peripheral nervous system is now clearly defined, and the spinal reflex has been moved to this section. New illustrations support improved discussions of all aspects of the nervous system. Chapter 9: The Sensory System Types of senses, rather than types of receptors, are now used to organize this chapter. The discussions of the anatomy and physiology of the eye and ear are better organized, with an emphasis on how information regarding vision and sound is generated and transmitted to the brain. The sense of equilibrium is now divided into rotational and gravitational equilibrium. Chapter 10: The Endocrine System An overview of the endocrine glands now precedes an improved discussion of each gland. A new illustration shows how the adrenal medulla and the adrenal cortex are involved in short-term and long-term stress, respectively. Other new illustrations pertain to regulation of blood calcium, regulation of blood pressure, Addison disease, and Cushing syndrome. The chapter also includes a discussion of chemical signals in general and how hormones affect cellular metabolism. Chapter 11: Blood A detailed description of the composition and function of blood now opens the chapter. There follows a more comprehensive look at the formed elements. The section on platelets centers around hemostasis, including coagulation. The transport function of blood is illustrated by considering capillary exchange. The last section of the chapter, Blood Typing and Transfusions, is supported by new art that clearly illustrates blood types and agglutination. Chapter 12: The Cardiovascular System An overview of the cardiovascular system, supported by an illustration, offers a much-improved introduction to the chapter, which has been reorganized into five parts: the anatomy of the heart, the physiology of the heart, the anatomy of blood vessels, the physiology of circulation, and circulatory routes. A better discussion of cardiac output and peripheral resistance improves the presentation of the chapter. Chapter 13: The Lymphatic System and Body Defenses As requested by reviewers, the lymphatic organs are now divided into those that are primary and those that are secondary. The discussion of specific immunity is much improved by new illustrations depicting the action of B cells and T cells. A new reading on emerging diseases modernizes the chapter. Chapter 14: The Respiratory System An improved Table 14.1, which includes a description of the respiratory organs, adds to the discussion of the respiratory system. The respiratory membrane is better described and is accompanied by a new illustration. The section entitled Mechanism of Breathing is better organized so that regulation of breathing rates now has its own subsection. Following reviewers’ suggestions, the chapter is more student friendly because gas exchange and transport no longer require a knowledge of partial pressures. All readings are new or extensively revised. x Preface
Mader: Understanding ② The McG ysiology, Fifth Edition Chapter 15: The Digestive System Teaching and Learning New illustrations of stomach and small intestine add to the improved and extended discussion of thes Supplements Chemical digestion now benefits by having its own McGraw-Hill offers various tools and teaching products to section. The Medical Focus reading"Human Teeth support the fifth edition of Understanding Human Anatomy moved to a logical location early in the chapter. Liver struc- Physiology. Students can order supplemental study materials ture, function, and disorders are more logically and thor- by contacting their local bookstore. Instructors can obtain oughly presented. The chapter ends with an added discussion teaching aids by calling the Customer Service Department at of three eating disorders: obesity, bulimia nervosa,an nd800-338-3987,visitingoura&pwebsiteatwww.mhhe.com, anorexia nervosa or contacting their local McGraw-Hill sales representative. The Digital Content Manager, 0-07-246443-7, is a multime- Chapter 16: The Urinary System and Excretion dia collection of visual resources that allows instructors to utilize artwork from the text in multiple formats to create The functions of the urinary system are discussed more thor- customized classroom presentations, visually-based tests and oughly than in the fourth edition. The discussion of a quizzes, dynamic course website content, or attractive nephron has been improved by the addition of micrographs. printed support materials. The digital assets on this cross- The role of the loop of the nephron and various hormones platform CD-ROM are grouped by chapter within the follow- water reabsorption is better explained, and the topic of acid- ing easy-to-use folde base balance has been expanded to discuss all the ways the body can adjust the ph of the blood. The chapter ends with a Active Art Library Key Process Figures are saved in ma- discussion of treatments for kidney failure. nipulable layers that can be isolated and customized to meet the needs of the lecture environment Chapter 17: The Reproductive System The topic of meiosis has been moved to this chapter so that permatogenesis and oogenesis can be better understood by students. Coverage of the reproductive organs has been im proved by the inclusion of both sagittal and posterior views of the systems. Following reviewers' suggestions, the menstrua (instead of the ovarian and uterine cycles) is discussed. Nev Health Focuses are provided on endocrine-disrupting con- taminants, shower checks for cancer, and preventing trans mission of stds Chapter 18: Human Development and Birth The addition of new figures depicting fertilization, extrem- gxrstesfr rd, acetytsche, When the bryonic membranes, and the primary germ layers improves this chapter. Extensive revision is obvious due to the addition of new readings entitled"Therapeutic Cloning " and"prevent Animations Library Numerous full-color ing Birth Defects. " A discussion of the development of male animations of key physiological processes are and female organs has been added, and the chapter ends with provided. Harness the visual impact of processes in a new and extended discussion of the effects of pregnancy on motion by importing these files into classroom pre- sentations or course websites Art Libraries Full-color digital files of all illustrations in the book, plus the same art saved Chapter 19: Human Genetics unlabeled and gray scale versions, can be readily Aside from having all sections revised and updated, the chap- incorporated into lecture presentations, exams, or ter uses cystic fibrosis to show the connection between a ge custom-made classroom materials. These images are netic disorder and the function of a protein and to illustrate also pre-inserted into blank Power Point slides for the levels of genetic counseling, from doing a pedigree to per- ease of use. forming a preimplantation genetic study. The chapter ends Photo Libraries Digital files of instructionally signif- with a Medical Focus outlining the future benefits from the icant photographs from the text-including cadaver modern field of genomics. bone, histology, and surface anatomy images-can be reproduced for multiple classroom uses Preface xi
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 Preface xi Chapter 15: The Digestive System New illustrations of stomach and small intestine anatomy add to the improved and extended discussion of these topics. Chemical digestion now benefits by having its own separate section. The Medical Focus reading “Human Teeth” has been moved to a logical location early in the chapter. Liver structure, function, and disorders are more logically and thoroughly presented. The chapter ends with an added discussion of three eating disorders: obesity, bulimia nervosa, and anorexia nervosa. Chapter 16: The Urinary System and Excretion The functions of the urinary system are discussed more thoroughly than in the fourth edition. The discussion of a nephron has been improved by the addition of micrographs. The role of the loop of the nephron and various hormones in water reabsorption is better explained, and the topic of acidbase balance has been expanded to discuss all the ways the body can adjust the pH of the blood. The chapter ends with a discussion of treatments for kidney failure. Chapter 17: The Reproductive System The topic of meiosis has been moved to this chapter so that spermatogenesis and oogenesis can be better understood by students. Coverage of the reproductive organs has been improved by the inclusion of both sagittal and posterior views of the systems. Following reviewers’ suggestions, the menstrual (instead of the ovarian and uterine cycles) is discussed. New Health Focuses are provided on endocrine-disrupting contaminants, shower checks for cancer, and preventing transmission of STDs. Chapter 18: Human Development and Birth The addition of new figures depicting fertilization, extraembryonic membranes, and the primary germ layers improves this chapter. Extensive revision is obvious due to the addition of new readings entitled “Therapeutic Cloning” and “Preventing Birth Defects.” A discussion of the development of male and female organs has been added, and the chapter ends with a new and extended discussion of the effects of pregnancy on the mother. Chapter 19: Human Genetics Aside from having all sections revised and updated, the chapter uses cystic fibrosis to show the connection between a genetic disorder and the function of a protein and to illustrate the levels of genetic counseling, from doing a pedigree to performing a preimplantation genetic study. The chapter ends with a Medical Focus outlining the future benefits from the modern field of genomics. Teaching and Learning Supplements McGraw-Hill offers various tools and teaching products to support the fifth edition of Understanding Human Anatomy & Physiology. Students can order supplemental study materials by contacting their local bookstore. Instructors can obtain teaching aids by calling the Customer Service Department at 800-338-3987, visiting our A & P website at www.mhhe.com, or contacting their local McGraw-Hill sales representative. The Digital Content Manager, 0-07-246443-7, is a multimedia collection of visual resources that allows instructors to utilize artwork from the text in multiple formats to create customized classroom presentations, visually-based tests and quizzes, dynamic course website content, or attractive printed support materials. The digital assets on this crossplatform CD-ROM are grouped by chapter within the following easy-to-use folders. • Active Art Library Key Process Figures are saved in manipulable layers that can be isolated and customized to meet the needs of the lecture environment. • Animations Library Numerous full-color animations of key physiological processes are provided. Harness the visual impact of processes in motion by importing these files into classroom presentations or course websites. • Art Libraries Full-color digital files of all illustrations in the book, plus the same art saved in unlabeled and gray scale versions, can be readily incorporated into lecture presentations, exams, or custom-made classroom materials. These images are also pre-inserted into blank PowerPoint slides for ease of use. • Photo Libraries Digital files of instructionally significant photographs from the text—including cadaver, bone, histology, and surface anatomy images—can be reproduced for multiple classroom uses
Mader: Understanding ② The McG Human Anatomy ysiology, Fifth Edition PowerPoints Ready-made image presentations cover each of the 19 chapters of the text. Tailor the PowerPoints to reflect your preferred lecture topics and sequences Tables Library Every table that appears in the text is provided in electronic form. You can quickly preview images and incorporate them into PowerPoint or other presentation programs to create your own multimedia presentations. You can also re- move and replace labels to suit your own preferences in terminology or level of detail. Instructor Testing and Resource CD-ROM, 0-07-246441-0, is a ross-platform CD-ROM providing a wealth of resources for the instructor. Supplements featured on this CD-ROM include a computerized test bank utilizing Brownstone Diploma@ testing software to quickly create customized content(and nearly every body system) including Urinary exams. This user-friendly program allows instructors to Skeletal, Reproductive, Nervous, Muscular, Immune, Diges- search for questions by topic or format, edit existing tive, Circulatory, and Endocrine. The Interactive Clinical questions or add new ones, and scramble questions and an- Resource CD-ROm may be used as a classroom lecture tool or swer keys for multiple versions of the same test study guide for students post lecture. Students can use the Interactive Clinical Resource CD-ROM to play the 3D anima Other assets on the Instructors Testing and Resource CD tions, explore the 3D models, print the associated text, and ROM are grouped within easy-to-use folders. The Instructors view the slides with labels and definitions of key structures re- anual and Clinical Applications Manual are available in lated to the disease/disorder. Students will learn how the var- both Word and PDF formats. Word files of the test bank are ious diseases/ disorders affect the human body system along included for those instructors who prefer to work outside of with possible treatments. The Interactive Clinical Resource CD-ROM is the perfect way to reinforce and relate the physio- The Instructor's Manual, by Dr. Patrick Galliart includes chapter logical concepts taught in the classroom to real life summariesandoutlinessuggestedstudentactivitiesanswerstoonLineLearningCenter(http://www.mhhe.com/maderap5) bjective questions and to medical terminology reinforcement The olC offers an extensive array of learning and teaching exercises, and a list of audiovisual materials. The Instructors tools. The site includes quizzes for each chapter, links to Manual is available on Instructor Testing and Resource CD- websites related to each chapter, clinical applications, ROM and the Instructor Edition of the Online Learning Center. interactive activities, art labeling exercises, and case studies McGraw-Hill provides 200 Overhead Transparencies, Instructor resources at the site include lecture outlines 0-07-246438-0 of key text line art and photographs echnology resources, clinical applications, and case studies English/Spanish Glossary for Anatomy and Physiology, Student Center, Online Essential Study Partner 0-07-283118-9, is a complete glossary that includes every key The ESP contains 120 animations and more than term used in a typical anatomy and physiology course. 800 learning activities to help your students grasp Definitions are provided in both English and Spanish. A complex concepts. Interactive diagrams and quizzes phonetic guide to pronunciation follows each word in the will make learning stimulating and fun for your stu- dents. The es als Study Partner can be acces via the Online learning Center Course Delivery Systems With help from our partners, WebCT, Blackboard, Top Class, e College, and other course management systems, professors can take com plete control over their course content. These course cartridges also provide online testing and powerful student tracking_line features. Understanding Human Anatomy& Physiology Onl Learning Center is available within all of these platforms or the student Interactive Clinical Resource cD-ROM The Interactive Clinical Resource CD-ROM offers one hun- he cemooss notne dred fifty-one 3D animations and 3D models of human dis- ease and disorders. It also contains 13 sections of clinical xi Preface
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 • PowerPoints Ready-made image presentations cover each of the 19 chapters of the text. Tailor the PowerPoints to reflect your preferred lecture topics and sequences. • Tables Library Every table that appears in the text is provided in electronic form. You can quickly preview images and incorporate them into PowerPoint or other presentation programs to create your own multimedia presentations. You can also remove and replace labels to suit your own preferences in terminology or level of detail. Instructor Testing and Resource CD-ROM, 0-07-246441-0, is a cross-platform CD-ROM providing a wealth of resources for the instructor. Supplements featured on this CD-ROM include a computerized test bank utilizing Brownstone Diploma® testing software to quickly create customized exams. This user-friendly program allows instructors to search for questions by topic or format, edit existing questions or add new ones, and scramble questions and answer keys for multiple versions of the same test. Other assets on the Instructor’s Testing and Resource CDROM are grouped within easy-to-use folders. The Instructor’s Manual and Clinical Applications Manual are available in both Word and PDF formats. Word files of the test bank are included for those instructors who prefer to work outside of the test generator software. The Instructor’s Manual, by Dr. Patrick Galliart includes chapter summaries and outlines, suggested student activities, answers to objective questions and to medical terminology reinforcement exercises, and a list of audiovisual materials. The Instructor’s Manual is available on Instructor Testing and Resource CDROM and the Instructor Edition of the Online Learning Center. McGraw-Hill provides 200 Overhead Transparencies, 0-07-246438-0 of key text line art and photographs. English/Spanish Glossary for Anatomy and Physiology, 0-07-283118-9, is a complete glossary that includes every key term used in a typical anatomy and physiology course. Definitions are provided in both English and Spanish. A phonetic guide to pronunciation follows each word in the glossary. Course Delivery Systems With help from our partners, WebCT, Blackboard, TopClass, eCollege, and other course management systems, professors can take complete control over their course content. These course cartridges also provide online testing and powerful student tracking features. Understanding Human Anatomy & Physiology Online Learning Center is available within all of these platforms. For the Student Interactive Clinical Resource CD-ROM The Interactive Clinical Resource CD-ROM offers one hundred fifty-one 3D animations and 3D models of human disease and disorders. It also contains 13 sections of clinical content (and nearly every body system) including Urinary, Skeletal, Reproductive, Nervous, Muscular, Immune, Digestive, Circulatory, and Endocrine. The Interactive Clinical Resource CD-ROM may be used as a classroom lecture tool or study guide for students post lecture. Students can use the Interactive Clinical Resource CD-ROM to play the 3D animations, explore the 3D models, print the associated text, and view the slides with labels and definitions of key structures related to the disease/disorder. Students will learn how the various diseases/disorders affect the human body system along with possible treatments. The Interactive Clinical Resource CD-ROM is the perfect way to reinforce and relate the physiological concepts taught in the classroom to real life. Online Learning Center (http://www.mhhe.com/maderap5) The OLC offers an extensive array of learning and teaching tools. The site includes quizzes for each chapter, links to websites related to each chapter, clinical applications, interactive activities, art labeling exercises, and case studies. Instructor resources at the site include lecture outlines, technology resources, clinical applications, and case studies. • Student Center, Online Essential Study Partner The ESP contains 120 animations and more than 800 learning activities to help your students grasp complex concepts. Interactive diagrams and quizzes will make learning stimulating and fun for your students. The Essentials Study Partner can be accessed via the Online Learning Center. xii Preface
Mader: Understanding Fro ② The McG Human Anatomy ysiology, Fifth Edition Live News feeds The Anatomy and Physiology Laboratory Textbook essentials The OLC offers course specific real-time news Version, 0-07-232363-9, by Gunstream, contains several frog articles to help students stay current with the latest dissections and may be used with any anatomy and physiol topics in anatomy and physiology ogy text. Tutorial Service This free" homework hotline"offers you the opportu- Human Anatomy and Physiology Laboratory Manual-Fetal Dissection, Second Edition 0-07-243814-2, by Terry R. Mar- nity to discuss text questions with our A&P consultant. tin, Kishwaukee College, provides excellent full-color photos GetBodySmart. com is an online examination of of the dissected fetal pig with corresponding labeled art. It human anatomy and physiology. This program is includes World wide Web activities for many chapters available on the student edition of the online learn- ing Cente Subnet argas circulatory的 8中4 ucation a bu avl sin l It超l旧naa,和 Access Science is the online version of mcgraw-Hill's Encyclopedia of Science Technology Link to this Virtual Anatomy dissection Review. CD-roM site free of charge from the Online Learning Center. 0-07-285621-1, by John Waters, Pennsylvania State Physiology Interactive Lab Simulations(Ph LLS) University. This multimedia program contains vivid, high 287167-9 quality, labeled cat dissection photographs. The program The Ph I LS CD-ROM contains eleven laboratory helps students easily identify and review the corresponding simulations that allow students to perform experiments structures and functions between the cat and the human without using expensive lab equipment or live animals. This asy-to-use software offers students the flexibility to change the parameters of every lab experiment, with no limit to the Laboratory Atlas of Anatomy and Physiology fourth edition, amount of times a student can repeat experiments or modify 0-07-243810-X, by Eder et al., is a full-color atlas containing variables. This power to manipulate each experiment histology, human skeletal anatomy, human muscular reinforces key physiology concepts by helping students to anatomy, dissections, and reference tables view outcomes, make predictions, and draw conclusions. Preface xiii
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 Preface xiii • Live News Feeds The OLC offers course specific real-time news articles to help students stay current with the latest topics in anatomy and physiology. • Tutorial Service This free “homework hotline” offers you the opportunity to discuss text questions with our A&P consultant. • GetBodySmart.com is an online examination of human anatomy and physiology. This program is available on the Student Edition of the Online Learning Center. The Anatomy and Physiology Laboratory Textbook Essentials Version, 0-07-232363-9, by Gunstream, contains several frog dissections and may be used with any anatomy and physiology text. Human Anatomy and Physiology Laboratory Manual-Fetal Pig Dissection, Second Edition 0-07-243814-2, by Terry R. Martin, Kishwaukee College, provides excellent full-color photos of the dissected fetal pig with corresponding labeled art. It includes World Wide Web activities for many chapters. • Access Science is the online version of McGraw-Hill’s Encyclopedia of Science & Technology. Link to this site free of charge from the Online Learning Center. Physiology Interactive Lab Simulations (Ph.I.L.S) 0-07-287167-9 The Ph.I.L.S CD-ROM contains eleven laboratory simulations that allow students to perform experiments without using expensive lab equipment or live animals. This easy-to-use software offers students the flexibility to change the parameters of every lab experiment, with no limit to the amount of times a student can repeat experiments or modify variables. This power to manipulate each experiment reinforces key physiology concepts by helping students to view outcomes, make predictions, and draw conclusions. Virtual Anatomy Dissection Review, CD-ROM, 0-07-285621-1, by John Waters, Pennsylvania State University. This multimedia program contains vivid, high quality, labeled cat dissection photographs. The program helps students easily identify and review the corresponding structures and functions between the cat and the human body. Laboratory Atlas of Anatomy and Physiology, fourth edition, 0-07-243810-X, by Eder et al., is a full-color atlas containing histology, human skeletal anatomy, human muscular anatomy, dissections, and reference tables
Mader: Understanding ② The McG ysiology, Fifth Edition Acknowledgments Fifth Edition reviewers I would like to acknowledge the valuable contributions of all Karen Magatagan professors and their students who have provided detailed re Cochise College ommendations for improving chapter content and illustr tions for the fifth edition Jacqueline S McLaughlin Bert Atma Kenneth Moore William I. Burke Madison Area Technical College Albert moras Boulder College of Massage Therapy Richard Ceron Scott murdoch Carnegie Institute of Integrative Medicine Moraine Valley Community College Jay P. Clymer Ill Linda r. nichols Marywood Uniwersity Santa Fe Community College Mark eberle Central Oregon Community College Robin r. patterson Butler County Community College Diana godish Ball State University Susan Pazynski Glen Oaks Community College Michelle A green Alfred State Colle Joel H. Scott Blue Cliff college Tulsa Community Colleg marilyn M. Shannon Dianne M. Jedlicka The School of the Art Institute of Chicago F. Christopher Sowers avannah College of Art and Design Michael Squires Diane M. Kelly James D. Tipton Broome Community College Chattahoochee Valley Community College Kenneth M. Kosten Community College of Denver Harry A. Tracy, Ir. University of Texas at San John ]. Kulig K Won Central Massachusetts School of Massage and Therapy Los angeles Trade-Technical College
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 xiv Preface I would like to acknowledge the valuable contributions of all professors and their students who have provided detailed recommendations for improving chapter content and illustrations for the fifth edition. Bert Atsma Union County College William J. Burke Madison Area Technical College Richard Ceroni Carnegie Institute of Integrative Medicine Jay P. Clymer III Marywood University Mark Eberle Central Oregon Community College Diana Godish Ball State University Michelle A. Green Alfred State College Gary W. Hunt Tulsa Community College Dianne M. Jedlicka The School of the Art Institute of Chicago Geoffrey Jowett Savannah College of Art and Design Diane M. Kelly Broome Community College Kenneth M. Kosten Community College of Denver John J. Kulig Central Massachusetts School of Massage and Therapy Karen Magatagan Cochise College Jacqueline S. McLaughlin Pennsylvania State University—Berks/Lehigh Valley Kenneth Moore Seattle Pacific University Albert Moraska Boulder College of Massage Therapy Scott Murdoch Moraine Valley Community College Linda R. Nichols Santa Fe Community College Robin R. Patterson Butler County Community College Susan Pazynski Glen Oaks Community College Joel H. Scott Blue Cliff College Marilyn M. Shannon Indiana University-Purdue University—Fort Wayne F. Christopher Sowers Wilkes Community College Michael Squires Columbus State Community College James D. Tipton Chattahoochee Valley Community College Harry A. Tracy, Jr. University of Texas at San Antonio Ricky K. Wong Los Angeles Trade-Technical College Acknowledgments Fifth Edition Reviewers
Mader: Understanding ② The McG ysiology, Fifth Edition The Focus is Understanding Students develop a working knowledge of anatomy and physiology based upon conceptual understanding. Clinical Applications broaden students'horizons beyond the core principles. Self-confidence increases as students master medical terminology and key concepts Art Program Art presents and reinforces the dynamic processes within the human bod The Muscular System Dynamic Photos give students a closer look inside the wonders of the human body through the technology of scanning electron micrographs N visual focus Visual Focus illustrates difficult concepts that relate structure to function, using a step-by New and revised art oncise labeling methodology that keeps students from getting bogged down with excessive detail The most beautiful thing we can experience as ausmus is the mysterious. It is the source of all true art and science
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 xv • Students develop a working knowledge of anatomy and physiology based upon conceptual understanding. • Clinical Applications broaden students’ horizons beyond the core principles. • Self-confidence increases as students master medical terminology and key concepts. Art Program Art presents and reinforces the dynamic processes within the human body. chapter The Muscular System Scanning electron micrograph of motor neurons terminating at muscle fibers. A muscle fiber receives the stimulus to contract at a neuromuscular junction. chapter outline & learning objectives After you have studied this chapter, you should be able to: 7.1 Functions and Types of Muscles (p. 114) ■ Distinguish between the three types of muscles, and tell where they are located in the body. ■ Describe the connective tissues of a skeletal muscle. ■ Name and discuss five functions of skeletal muscles. 7.2 Microscopic Anatomy and Contraction of Skeletal Muscle (p. 116) ■ Name the components of a skeletal muscle fiber, and describe the function of each. ■ Explain how skeletal muscle fibers are innervated and how they contract. ■ Describe how ATP is made available for muscle contraction. 7.3 Muscle Responses (p. 122) ■ Contrast the responses of a muscle fiber and whole muscle in the laboratory with their responses in the body. ■ Contrast slow-twitch and fast-twitch muscle fibers. 7.4 Skeletal Muscles of the Body (p. 124) ■ Discuss how muscles work together to achieve the movement of a bone. ■ Give examples to show how muscles are named. ■ Describe the locations and actions of the major skeletal muscles of each body region. 7.5 Effects of Aging (p. 134) ■ Describe the anatomical and physiological changes that occur in the muscular system as we age. 7.6 Homeostasis (p. 136) ■ Describe how the muscular system works w other systems of the body to maintain homeostasis. ■ Describe some common muscle disorders a some of the serious diseases that can affec muscles. Visual Focus Anatomy of a Muscle Fiber (p. 117) Medical Focus Benefits of Exercise (p. 135) 113 Dynamic Photos give students a closer look inside the wonders of the human body through the technology of scanning electron micrographs. Visual Focus illustrates difficult concepts that relate structure to function, using a step-bystep process. New and Revised Art focuses on the main concepts by using concise labeling methodology that keeps students from getting bogged down with excessive detail. Chapter 7 The Muscular System 117 Figure 7.3 Anatomy of a muscle fiber. A muscle fiber contains many myofibrils with the components shown. A myofibril has many sarcomeres that contain myosin and actin filaments whose arrangement gives rise to the striations so characteristic of skeletal muscle. Muscle contraction occurs when sarcomeres contract and actin filaments slide past myosin filaments. bundle of muscle fibers muscle fiber T tubules nucleus sarcoplasm sarcolemma cross-bridge myosin actin sarcoplasmic reticulum calcium storage sites one sarcomere Z line Z line H zone Z line Muscle fiber has many myofibrils. skeletal muscle fiber one myofibril A band I band Myofibril has many sarcomeres. Sarcomere is relaxed. Sarcomere is contracted. Muscles of the Abdominal Wall The abdominal wall has no bony reinforcement (Fig. 7.14). The wall is strengthened by four pairs of muscles that run at angles to one another. The external and internal obliques and the transversus abdominis occur laterally, but the fasciae of these muscle pairs meet at the midline of the body, forming a tendinous area called the linea alba. The rectus abdominis is fi i l di l i f l Muscles of the Shoulder Muscles of the shoulder are shown in Figures 7.14 and 7.15. They are also listed in Table 7.4 on page 130. The muscles of the shoulder attach the scapula to the thorax and move the scapula; they also attach the humerus to the scapula and move the arm. Figure 7.15 Muscles of the posterior shoulder. The right trapezius is removed to show deep muscles that move the scapula and the rotator cuff muscles. trapezius deltoid latissimus dorsi rotator cuff muscles “The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.” – Albert Einstein
Mader: Understanding ② The McG ysiology, Fifth Edition Macro to micro presentation helps students make the connection between gross anatomy and microscopic anatomy. Correlation of Photomicrographs with line art makes it easier for students to identify specific structures Reference Figures of the human body have been dded to give students an dditional resource in the study of body structure
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 Chapter 6 The Skeletal System 85 articular cartilage spongy bone (contains red bone marrow) blood vessel trabeculae medullary cavity (contains yellow bone marrow) periosteum Epiphysis Diaphysis Epiphysis Humerus Compact Bone compact bone Spongy Bone osteon lamella endosteum epiphyseal plates canaliculi b. a. osteocyte within lacuna blood vessels central canal Figure 6.2 Anatomy of a long bone. a. A long bone is encased by the periosteum except at the epiphyses, which are covered by articular cartilage. Spongy bone of the epiphyses contains red bone marrow. The diaphysis contains yellow bone marrow and is bordered by compact bone. b. The detailed anatomy of spongy bone and compact bone is shown in the enlargement, along with a blowup of an osteocyte in a lacuna. 4.2 Connective Tissue Connective tissue binds structures together, provides support and protection, fills spaces, produces blood cells, and stores fat. The body uses this stored fat for energy, insulation, and organ protection. As a rule, connective tissue cells are widely separated by an extracellular matrix composed of an organic ground substance that contains fibers and varies in consistency from solid to semifluid to fluid. Whereas the functional and physical properties of epithelial tissues are derived from its cells, connective tissue properties are largely derived from the characteristics of the matrix (Table 4.2). The fibers within the matrix are of three types. White fibers contain collagen, a substance that gives the fibers flexibility and strength. Yellow fibers contain elastin, which is not as strong as collagen but is more elastic. Reticular fibers are very thin, highly branched, collagenous fibers that form delicate supporting networks. ground substance fibroblast elastic fiber collagenous fiber Loose (Areolar) Connective Tissue Location: Between muscles; beneath the skin; beneath most epithelial layers Function: Binds organs together Figure 4.5 Loose (areolar) connective tissue. This tissue has a loose network of fibers. Appendix A 409 Plate 6 The torso as viewed with the heart, liver, stomach, and portions of the small and large intestines removed. (a. artery; m. muscle; v. vein.) esophagus trachea left subclavian a. left subclavian v. left brachiocephalic v. arch of aorta descending aorta diaphragm spleen celiac a. pancreas left kidney inferior mesenteric a. left common iliac a. descending colon (cut) sigmoid colon ovary uterus rectus femoris m. (cut) urinary bladder symphysis pubis vastus lateralis m. vastus intermedius m. right internal jugular v. right common carotid a. superior vena cava right bronchus esophagus pleural cavity inferior vena cava adrenal gland right kidney duodenum superior mesenteric v. superior mesenteric a. ureter sartorius m. (cut) tensor fascia latae m. (cut) rectus femoris m. adductor longus m. gracilis m. pericardial cavity adductor brevis m. Macro to Micro Presentation helps students make the connection between gross anatomy and microscopic anatomy. Correlation of Photomicrographs with Line Art makes it easier for students to identify specific structures. Reference Figures of the human body have been added to give students an additional resource in the study of body structure. xvi
Mader: Understanding ② The McG ysiology, Fifth Edition Clinical Connections Additional readings engage the students by creating a richer understanding of the concepts presented and provide a real life connection to anatomy and physiology Medical Focus Readings Medical focus encourage students to explore clinical examples that they may see through heir health care career or within thei What's ney What's New Readings ffer fascinating information on treatments now experimental but promise to be particularly helpful in the future Effects of Aging Effects of Aging presents some of the age- related physical and Education is not preparation for life; education is life itself. John D
Mader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 Clinical Connections Additional readings engage the students by creating a richer understanding of the concepts presented and provide a real life connection to anatomy and physiology. 88 Part II Support, Movement, and Protection Osteoporosis Osteoporosis is a condition in which the bones are weakened due to a decrease in the bone mass that makes up the skeleton. Throughout life, bones are continuously remodeled. While a child is growing, the rate of bone formation is greater than the rate of bone breakdown. The skeletal mass continues to increase until ages 20 to 30. After that, the rates of formation and breakdown of bone mass are equal until ages 40 to 50. Then, reabsorption begins to exceed formation, and the total bone mass slowly decreases. Over time, men are apt to lose 25% and women 35% of their bone mass. But we have to consider that men tend to have denser bones than women anyway, and their testosterone (male sex hormone) level generally does not begin to decline significantly until after age 65. In contrast, the estrogen (female sex hormone) level in women begins to decline at about age 45. Because sex hormones play an important role in maintaining bone strength, this difference means that women are more likely than men to suffer fractures, involving especially the hip, vertebrae, long bones, and pelvis. Although osteoporosis may at times be the result of various disease processes, it is essentially a disease of aging. Everyone can take measures to avoid having osteoporosis when they get older. Adequate dietary calcium throughout life is an important protection against osteoporosis. The U.S. National Institutes of Health recommend a calcium intake of 1,200–1,500 mg per day during puberty. Males and females require 1,000 mg per day until age 65 and 1,500 mg per day after age 65, because the intestinal tract has fewer vitamin D receptors in the elderly. A small daily amount of vitamin D is also necessary to absorb calcium from the digestive tract. Exposure to sunlight is required to allow skin to synthesize vitamin D. If you reside on or north of a “line” drawn from Boston to Milwaukee, to Minneapolis, to Boise, chances are, you’re not getting enough vitamin D during the winter months. Therefore, you should avail yourself of the vitamin D in fortified foods such as low-fat milk and cereal. Postmenopausal women should have an evaluation of their bone density. Presently, bone density is measured by a method called dual energy X-ray absorptiometry (DEXA). This test measures bone density based on the absorption of photons generated by an X-ray tube. Soon, a blood and urine test may be able to detect the biochemical markers of bone loss, making it possible for physicians to screen all older women and at-risk men for osteoporosis. If the bones are thin, it is worthwhile to take measures to gain bone density because even a slight increase can significantly reduce fracture risk. Regular, moderate, weight-bearing exercise such as walking or jogging is a good way to maintain bone strength (Fig. 6A). A combination of exercise and drug treatment, as recommended by a physician, may yield the best results. A wide variety of prescribed drugs that have different modes of action are available. Hormone therapy includes black cohosh, which is a phytoestrogen (estrogen made by a plant as opposed to an animal). Calcitonin is a naturally occurring hormone whose main site of action is the skeleton where it inhibits the action of osteoclasts, the cells that break down bone. Promising new drugs include slow-release fluoride therapy and certain growth hormones. These medications stimulate the formation of new bone. a. b. osteoporosis normal bone Figure 6A Preventing osteoporosis. a. Exercise can help prevent osteoporosis, but when playing golf, you should carry your own clubs and walk instead of using a golf cart. b. Normal bone growth compared to bone from a person with osteoporosis. Chapter 6 The Skeletal System 107 Coaxing the Chondrocytes for Knee Repair To the young, otherwise healthy, 30-something athlete on the physician’s exam table, the diagnosis must seem completely unfair. Perhaps he’s a former football player, or she’s a trained dancer. Whatever the sport or activity, the patient is slender and fit, but knee pain and swelling are this athlete’s constant companions. Examination of the knee shows the result of decades of use and abuse while performing a sport: The hyaline cartilage, also called articular cartilage, of the knee joint has degenerated. Hyaline cartilage (see page 84) is the "Teflon coating" for the bones of freely movable joints such as the knee. Hyaline cartilage allows easy, frictionless movement between the bones of the joint. Once repeated use has worn it away, hyaline cartilage does not grow back naturally. Exposed bone ends can grind against one another, resulting in pain, swelling, and restricted movements that can cripple the athlete. In severe cases, total knee replacement with a prosthetic joint is the athlete’s only option (Fig. 6B). Now the technique of tissue culture (growing cells outside of the patient’s body in a special medium) can help young athletes with cartilage injuries regenerate their own hyaline cartilage. In an autologous chondrocyte implantation (ACI) surgery, a piece of healthy hyaline cartilage from the patient’s knee is first removed surgically. This piece of cartilage, about the size of a pencil eraser, is typically taken from an undamaged area at the top edge of the knee. The chondrocytes, living cells of hyaline cartilage, are grown outside the body in tissue culture medium. Millions of the patient’s own cells can be grown to create a "patch" of living cartilage. Growing these cells takes two to three weeks. Once the chondrocytes have grown, a pocket is created over the damaged area using the patient’s own periosteum, the connective tissue that surrounds the bone (see page 84). The periosteum pocket will hold the hyaline cartilage cells in place. The cells are injected into the pocket and left to grow. As with all injuries to the knee, once the cartilage cells are firmly established, the patient still faces a lengthy rehabilitation. The patient must use crutches or a cane for three to four months to protect the joint. Physical therapy will stimulate cartilage growth without overstressing the area being repaired. In six months, the athlete can return to light-impact training and jogging. Full workouts can be resumed in about one year after surgery. However, most patients regain full mobility and a pain-free life after ACI surgery and do not have to undergo total knee replacement. ACI surgery can’t be used for the elderly or for overweight patients with osteoarthritis. Muscle or bone defects in the knee joint must be corrected before the surgery can be attempted. As with all surgeries, there is a risk for postoperative complications, such as bleeding or infection. However, ACI may offer young athletes the chance to restore essential hyaline cartilage and regain a healthy, functional knee joint. polyethylene polyethylene pelvis femur femur a. tibia b. Figure 6B Artificial joints in which polyethylene replaces articular cartilage. a. Knee. b. Hip. 6.5 Effects of Aging Both cartilage and bone tend to deteriorate as a person ages. The chemical nature of cartilage changes, and the bluish color typical of young cartilage changes to an opaque, yellowish color. The chondrocytes die, and reabsorption occurs as the cartilage undergoes calcification, becoming hard and brittle. Calcification interferes with the ready diffusion of nutrients and waste products through the matrix. The articular cartilage may no longer function properly, and the symptoms of arthritis can appear. There are three common types of arthritis: (1) Osteoarthritis is accompanied by deterioration of the articular cartilage. (2) In rheumatoid arthritis, the synovial membrane becomes inflamed and grows thicker cartilage, possibly due to an autoimmune reaction. (3) Gout, or gouty arthritis, is caused by an excessive buildup of uric acid (a metabolic waste) in the blood. Rather than being excreted in the urine, the acid is deposited as crystals in the joints, where it causes inflammation and pain. Osteoporosis, discussed in the Medical Focus on page 88, is present when weak and thin bones cause aches and pains. Such bones tend to fracture easily. Effects of Aging presents some of the age-related physical and functional changes that occur in the body. What’s New Readings offer fascinating information on treatments that are now experimental but promise to be particularly helpful in the future. Medical Focus Readings encourage students to explore clinical examples that they may see throughout their health care career or within their own family. “Education is not preparation for life; education is life itself.” – John Dewey xvii
