Essentials of Anatomy and Physiology ( PDFDrive ) (1).pdf

00Scanlon(p3) Cover 8/17/06 10:39 AM Page 2 List of Boxes Clinical applications of the book’s anatomical and physiological information are set apart from the text in boxed inserts and often deal with aspects of pathophysiology. A list of these boxes is presented here for your convenience. 1-1 Replacing Tissues and Organs, 6 1-2 Visualizing the Interior of the Body, 18 2-1 Blood Gases, 30 2-2 Nitric Oxide, 31 2-3 Lipids in the Blood, 36 2-4 A Protein Mystery: Prions, 39 3-1 Terminology of Solutions, 53 3-2 Genetic Disease – Sickle-Cell Anemia, 59 3-3 Abnormal Cellular Functioning – Cancer, 61 4-1 Cystic Fibrosis, 74 4-2 Vitamin C and Collagen, 78 4-3 Cosmetic Collagen, 78 5-1 Burns, 92–93 5-2 Preventing Skin Cancer: Common Sense and Sunscreens, 94 5-3 Common Skin Disorders, 97 5-4 Administering Medications, 100 6-1 Fractures and Their Repair, 111 6-2 Osteoporosis, 113 6-3 Herniated Disc, 121 6-4 Abnormalities of the Curves of the Spine, 122 6-5 Arthritis, 130 7-1 Anabolic Steroids, 141 7-2 Tetanus and Botulism, 146 7-3 Muscular Dystrophy, 148 7-4 Myasthenia Gravis, 148 7-5 Common Injection Sites, 149 8-1 Multiple Sclerosis, 168 8-2 Shingles, 174 8-3 Spinal Cord Injuries, 176 8-4 Cerebrovascular Accidents, 181 8-5 Aphasia, 182 8-6 Alzheimer’s Disease, 183 8-7 Parkinson’s Disease, 184 8-8 Lumbar Puncture, 187 9-1 Cataracts, 205 9-2 Glaucoma, 207 9-3 Errors of Refraction, 208 9-4 Night Blindness and Color Blindness, 209 9-5 Deafness, 214 9-6 Motion Sickness, 216 10-1 Disorders of Growth Hormone, 230 10-2 Disorders of Thyroxine, 235 10-3 Diabetes Mellitus, 238 10-4 Disorders of the Adrenal Cortex, 242 11-1 Anemia, 257 11-2 Jaundice, 259 11-3 Rh Disease of the Newborn, 261 11-4 Leukemia, 263 11-5 White Blood Cell Types: HLA, 264 11-6 Hemophilia, 266 11-7 Dissolving Clots, 268 12-1 Coronary Artery Disease, 280 (List of boxes continued on inside back cover) 00Scanlon(p3)-FM 8/17/06 10:40 AM Page i 00Scanlon(p3)-FM 8/17/06 10:40 AM Page ii 00Scanlon(p3)-FM 8/17/06 10:40 AM Page iii Valerie C. Scanlon, PhD College of Mount Saint Vincent Riverdale, New York Tina Sanders Medical Illustrator Castle Creek, New York Formerly Head Graphic Artist Tompkins Cortland Community College Dryden, New York 00Scanlon(p3)-FM 8/17/06 8:43 PM Page iv F. A. Davis Company 1915 Arch Street Philadelphia, PA 19103 www.fadavis.com Copyright © 2007 by F. A. Davis Company Copyright © 1991, 1995, 1999, and 2003 by F. A. Davis Company. All rights reserved. This product is protected by copyright. No part of it may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, pho- tocopying, recording, or otherwise, without written permission from the publisher. Printed in the United States of America Last digit indicates print number: 10 9 8 7 6 5 4 3 2 1 Nursing Editor: Lisa B. Deitch Developmental Editor: Alan Sorkowitz Project Editor: Ilysa H. Richman Cover Designer: Carolyn O’Brien As new scientific information becomes available through basic and clinical research, rec- ommended treatments and drug therapies undergo changes. The author(s) and publisher have done everything possible to make this book accurate, up to date, and in accord with accepted standards at the time of publication. The author(s), editors, and publisher are not responsible for errors or omissions or for consequences from application of the book, and make no warranty, expressed or implied, in regard to the contents of the book. Any prac- tice described in this book should be applied by the reader in accordance with professional standards of care used in regard to the unique circumstances that may apply in each situ- ation. The reader is advised always to check product information (package inserts) for changes and new information regarding dose and contraindications before administering any drug. Caution is especially urged when using new or infrequently ordered drugs. Library of Congress Cataloging-in-Publication Data Scanlon, Valerie C., Essentials of anatomy and physiology/ Valerie C. Scanlon, Tina Sanders. — 5th ed. p. ; cm. Includes index. ISBN–13: 978-0-8036-1546-5 ISBN–10: 0-8036-1546-9 1. Human anatomy. 2. Human physiology. I. Sanders, Tina, 1943-. II. Title. III. Title: Anatomy and physiology. [DNLM: 1. Anatomy. 2. Physiology. QS 4 S283e 2006] QP34.5.S288 2006 612—dc22 2006015120 Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by F. A. Davis Company for users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the fee of $.10 per copy is paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. For those organizations that have been granted a photocopy license by CCC, a separate system of payment has been arranged. The fee code for users of the Transactional Reporting Service is: 8036-1546/07 0 ! $.10. 00Scanlon(p3)-FM 8/17/06 10:40 AM Page v Preface A fifth edition of Essentials of Anatomy and Physiology is very gratifying, and again we have the pleasure of thanking all of our colleagues in teaching who continue to use our textbook and of welcoming new teachers and students. Changes have been made in the content of the book to keep the material as current as possible. Most of these are small changes, such as a new cell organelle, the protea- some, in Chapter 3; a clarification of blood cell production in Chapters 4, 11, and 14; and the addition of concentric and eccentric contractions to Chapter 7. The most extensive revision is in Chapter 14: The section on immunity has been rewritten using the categories of innate and adaptive immunity. New illustrations in this edition include positive and negative feedback mechanisms in Chapter 1, cellular transport mechanisms in Chapter 3, hormones that affect blood pressure in Chapter 13, innate immunity in Chapter 14, and synthesis uses of foods in Chapter 17. Illustrations that have been revised include protein structure, active site theory, and DNA and RNA structure in Chapter 2, blood cells in Chapter 11, and adaptive immunity in Chapter 14. Also new to this edition are illustration questions. Each figure legend is followed by a question for the student; the answers are in Appendix G. As always, your comments and suggestions will be most welcome, and they may be sent to us in care of the publisher: F. A. Davis Company, 1915 Arch Street, Philadelphia, PA 19103. Valerie C. Scanlon Dobbs Ferry, New York Tina Sanders Castle Creek, New York v 00Scanlon(p3)-FM 8/17/06 10:40 AM Page vi To the Instructor A s the science and arts of medicine and health care become increasingly complex, so too does the education of those who pursue careers in nursing and other health- related fields. Human anatomy and physiology is often a first course in many education programs, and is the basis for so many of the more specialized courses. Teachers of introductory anatomy and physiology thus take on a special challenge: We must distill and express the complexities of human structure and function in a simple way, without losing the essence and meaning of the material. That is the goal of this textbook: to make this material readily accessible to students with diverse backgrounds and varying levels of educational preparation. No prior knowledge of biology or chemistry is assumed, and even the most funda- mental terms are defined thoroughly. Essential aspects of anatomy are presented clearly and reinforced with excellent illustrations. Essential aspects of physiology are discussed simply, yet with accuracy and precision. Again, the illustrations complement the text material and foster comprehension on the part of the student. These illustrations were prepared especially for students for whom this is a first course in anatomy and physiology. As you will see, these are images in which detail is readily apparent. All important parts have been labeled, but the student is not overwhelmed with unnecessary labels. Illustrations of physiology lead the student step-by-step. Wherever appropriate, the legends refer students to the text for further description or explanation. Each illustration also has a question for the student; the illustration questions in a chapter form an ongoing self-test. (The answers are given in Appendix G.) The text has three unifying themes: the relationship between physiology and anatomy, the interrelations among the organ systems, and the relationship of each organ system to homeostasis. Although each type of cell, tissue, organ, or organ system is discussed simply and thoroughly in itself, applicable connections are made to other aspects of the body or to the functioning of the body as a whole. Our goal is to provide your students with the essentials of anatomy and physiology, and in doing so, to help give them a solid foundation for their future work, and an appreciation for the incredible living organism that is the human body. The sequence of chapters is a very traditional one. Cross-references are used to remind students of what they have learned from previous chapters. Nevertheless, the textbook is very flexible, and, following the introductory four chapters, the organ systems may be covered in almost any order, depending on the needs of your course. Each chapter is organized from the simple to the more complex, with the anatomy followed by the physiology. The Instructor’s Guide presents modifications of the topic sequences that may be used, again depending on the needs of your course. Certain more advanced topics may be omitted from each chapter without losing the meaning or flow of the rest of the material, and these are indicated, for each chapter, in the Instructor’s Guide. Clinical applications are set apart from the text in boxed inserts. These are often aspects of pathophysiology that are related to the normal anatomy or physiology in the text discussion. Each box presents one particular topic and is referenced at the appropriate point in the text. This material is intended to be an integral part of the chapter vi 00Scanlon(p3)-FM 8/17/06 10:40 AM Page vii To the Instructor vii but is set apart for ease of reference and to enable you to include or omit as many of these topics as you wish. The use of these boxes also enables students to read the text material without interruption and then to focus on specific aspects of pathophysiology. A comprehensive list of the boxes appears inside the book’s front and back covers, and another list at the beginning of each chapter cites the boxes within that chapter. Tables are utilized as summaries of structure and function, to present a sequence of events, or additional material that you may choose to include. Each table is referenced in the text and is intended to facilitate your teaching and to help your students learn. New terms appear in bold type within the text, and all such terms are fully defined in an extensive glossary, with phonetic pronunciations. Bold type may also be used for emphasis whenever one of these terms is used again in a later chapter. Each chapter begins with a chapter outline and student objectives to prepare the student for the chapter itself. New terminology and related clinical terms are also listed, with phonetic pronunciations. Each of these terms is fully defined in the glossary, with cross-references back to the chapter in which the term is introduced. At the end of each chapter are a study outline and review questions. The study outline includes all of the essentials of the chapter in a concise outline form. The review questions may be assigned as homework, or used by the students as a review or self- test. Following each question is a page reference in parentheses. This reference cites the page(s) in the chapter on which the content needed to answer the question correctly can be found. The answers themselves are included in the Instructor’s Guide. The questions in the sections titled For Further Thought may be used in a variety of ways, and the answers are in the Instructor’s Guide. An important supplementary learning tool for your students is available in the form of a Student Workbook that accompanies this text. For each chapter in the textbook, the workbook offers fill-in and matching-column questions, figure-labeling and figure- coloring exercises, and crossword puzzles based on the chapter’s vocabulary list. Also included are two comprehensive, multiple-choice chapter tests to provide a thorough review. All answers are provided at the end of the workbook. Ancillary materials for the teacher using this text are all on a CD-ROM: a complete Instructor’s Guide, two computerized test banks, and an Image Ancillary presentation of the text illustrations. The Instructor’s Guide contains notes on each chapter’s organization and content (useful for modifying the book to your specific teaching needs), topics for class discussion, answers to the chapter review questions from the textbook, and detailed answers to the For Further Thought questions. The multiple- choice test bank contains more than 2600 questions that have been organized in relation to the chapter review questions, and further explanation may be found in the Instructor’s Guide. The fill-in test bank contains more than 2100 questions organized by textbook chapter. The Image Ancillary presentation contains many of the illustrations from the textbook, with suggested points for use in classroom lectures. Suggestions and comments from colleagues are always valuable, and yours would be greatly appreciated. When we took on the task of writing and illustrating this textbook, we wanted to make it the most useful book possible for you and your students. Any suggestions that you can provide to help us achieve that goal are most welcome, and they may be sent to us in care of F. A. Davis Company, 1915 Arch Street, Philadelphia, PA 19103. Valerie C. Scanlon Dobbs Ferry, New York Tina Sanders Castle Creek, New York 00Scanlon(p3)-FM 8/17/06 10:40 AM Page viii To the Student T his is your textbook for your first course in human anatomy and physiology, a subject that is both fascinating and rewarding. That you are taking such a course says something about you. You may simply be curious as to how the human body functions or you may have a personal goal of making a contribution in one of the healthcare professions. Whatever your reason, this textbook will help you to be successful in your anatomy and physiology course. The material is presented simply and concisely, yet with accuracy and precision. The writing style is informal yet clear and specific; it is intended to promote your comprehension and understanding. ORGANIZATION OF THE TEXTBOOK To use this textbook effectively, you should know the purpose of its various parts. Each chapter is organized in the following way: Chapter Outline—This presents the main topics in the chapter, which corre- spond to the major headings in the text. Student Objectives—These summarize what you should know after reading and studying the chapter. These are not questions to be answered, but are rather, with the chapter outline, a preview of the chapter contents. New Terminology and Related Clinical Terminology—These are some of the new terms you will come across in the chapter. Read through these terms before you read the chapter, but do not attempt to memorize them just yet. When you have finished the chapter, return to the list and see how many terms you can define. Note those you may not be sure of and look them up. All of these terms are fully defined in the glossary. Study Outline—This is found at the end of the chapter. It is a concise summary of the essentials in the chapter. You may find this outline very useful as a quick review before an exam. Review Questions—These are also at the end of the chapter. Your instructor may assign some or all of them as homework. If not, the questions may be used as a self-test to evaluate your comprehension of the chapter’s content. The page number(s) in parentheses following each question refers you to the page(s) in the chapter on which the content needed to answer the question correctly can be found. For Further Thought—The heading tells you what these are for: thinking. Your instructor may use these for class discussion, and, if so, please do not ever be afraid to be wrong. Being wrong in the classroom is one of the ways each and every one of us learns. Contribute, raise your hand and speak up with your best thoughts, and listen to those of others. Together you will find the answers. viii 00Scanlon(p3)-FM 8/17/06 10:40 AM Page ix To the Student ix OTHER FEATURES WITHIN EACH CHAPTER Illustrations—These are an essential part of this textbook. Use them. Study them carefully, and they will be of great help to you as you learn. They are intended to help you develop your own mental picture of the body and its parts and processes. You may not have thought of mental pictures as being important, but they are, and each new one you create is a major step in learning. Each illustration is referenced in the text, so you will know when to con- sult it. With a little concentration, you will have it in your mind for whenever you need it. You will see that each illustration also has a question after the legend. These questions provide an ongoing quiz; try to answer each one as you come to it. (Will it matter if you’re wrong? No, but answering the questions will help you to learn.) The answers are given in Appendix G, just before the glossary. Boxes—Discussions of clinical applications are in separate boxes in the text so that you may find and refer to them easily. Your instructor may include all or some of these as required reading. If you are planning a career in the health professions, these boxes are an introduction to pathophysiology, and you will find them interesting and helpful. Bold Type—This is used whenever a new term is introduced, or when an old term is especially important. The terms in bold type are fully defined in the glossary, which includes phonetic pronunciations. Tables—This format is used to present material in a very concise form. Some tables are summaries of text material and are very useful for a quick review. Other tables present additional material that complements the text material. Glossary—Not within the chapters but at the end, the glossary is the diction- ary of the book. All of the terms in bold type, as well as others, are defined here. Make use of it, rather than wonder what a word means. The sooner you have a definition firmly in your mind, the sooner it is truly part of your knowledge. To make the best use of your study time, a Student Workbook is available that will help you to focus your attention on the essentials in each chapter. Also included are comprehensive chapter tests to help you determine which topics you have learned thoroughly and which you may have to review. If your instructor has not made the workbook a required text, you may wish to ask that it be ordered and made available in your bookstore. You will find it very helpful. SOME FINAL WORDS OF ENCOURAGEMENT Your success in this course depends to a great extent on you. Try to set aside study time for yourself every day; a little time each day is usually much more productive than trying to cram at the last minute. Ask questions of yourself as you are studying. What kinds of questions? The simplest ones. If you are studying a part of the body such as an organ, ask yourself: What is its name? Where is it? What is it made of? What does it do? That is: name, location, structure, and function. These are the essentials. If you are studying a process, ask yourself: What is happening here? What is its purpose? That is: What is going on? And what good is it? Again, these are the essentials. 00Scanlon(p3)-FM 8/17/06 10:40 AM Page x x To the Student We hope this textbook will contribute to your success. If you have any suggestions or comments, we would very much like to hear them. After all, this book was written for you, to help you achieve your goals in this course and in your education. Please send your suggestions and comments to us in care of F. A. Davis Company, 1915 Arch Street, Philadelphia, PA 19103. Valerie C. Scanlon Tina Sanders Dobbs Ferry, New York Castle Creek, New York 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xi Acknowledgments W riting and illustrating are part of a book, yet never the whole, and we thank the editors and production staff of the F. A. Davis Company, especially: Lisa Deitch, Nursing Editor Alan Sorkowitz, of Alan Sorkowitz Editorial Services, Developmental Editor Bob Butler, Production Editor Michael Bailey, Director of Production Patti Cleary, Editor in Chief, Nursing Ilysa Richman, Project Editor, Nursing Lisa Thompson, Project Editor, Production Lorretta Palagi, Copy Editor Carolyn O’Brien, for designing the layout and the cover Neil Kelly, director of sales, and all of the F. A. Davis sales representatives VCS TS To my students, past and present VCS To Brooks, for his encouragement TS xi 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xii Contents CHAPTER 1 Organization and General Plan of the Body.........1 Levels of Organization, 4 Metabolism and Homeostasis, 7 Terminology and General Plan of the Body, 12 CHAPTER 2 Some Basic Chemistry.....................................21 Elements, 24 Atoms, 24 Chemical Bonds, 25 Chemical Reactions, 28 Inorganic Compounds of Importance, 28 Organic Compounds of Importance, 33 CHAPTER 3 Cells............................................................46 Cell Structure, 48 Cellular Transport Mechanisms, 52 The Genetic Code and Protein Synthesis, 56 Cell Division, 60 Aging and Cells, 63 CHAPTER 4 Tissues and Membranes..................................67 Epithelial Tissue, 70 Connective Tissue, 74 Muscle Tissue, 79 Nerve Tissue, 81 Membranes, 82 Aging and Tissues, 84 CHAPTER 5 The Integumentary System..............................88 The Skin, 90 Subcutaneous Tissue, 99 Aging and the Integumentary System, 101 CHAPTER 6 The Skeletal System......................................104 Functions of the Skeleton, 106 Types of Bone Tissue, 106 Classification of Bones, 106 Embryonic Growth of Bone, 108 Factors That Affect Bone Growth and Maintenance, 108 The Skeleton, 112 xii 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xiii Contents xiii Joints—Articulations, 128 Aging and the Skeletal System, 128 CHAPTER 7 The Muscular System....................................135 Muscle Structure, 138 Muscle Tone, 140 Muscle Sense, 141 Energy Sources for Muscle Contraction, 141 Muscle Fiber—Microscopic Structure, 142 Contraction—The Sliding Filament Mechanism, 146 Responses to Exercise—Maintaining Homeostasis, 147 Aging and the Muscular System, 149 Major Muscles of the Body, 149 CHAPTER 8 The Nervous System......................................163 Nervous System Divisions, 166 Nerve Tissue, 166 Types of Neurons, 170 Nerves and Nerve Tracts, 171 The Nerve Impulse, 171 The Spinal Cord, 171 The Brain, 176 Meninges and Cerebrospinal Fluid, 184 Cranial Nerves, 186 The Autonomic Nervous System, 187 Aging and the Nervous System, 191 CHAPTER 9 The Senses..................................................196 Sensory Pathway, 198 Characteristics of Sensations, 198 Cutaneous Senses, 199 Muscle Sense, 200 Sense of Taste, 200 Sense of Smell, 202 Hunger and Thirst, 202 The Eye, 202 The Ear, 210 Arterial Receptors, 216 Aging and the Senses, 216 CHAPTER 10 The Endocrine System...................................221 Chemistry of Hormones, 225 Regulation of Hormone Secretion, 225 The Pituitary Gland, 225 Thyroid Gland, 231 Parathyroid Glands, 233 Pancreas, 233 Adrenal Glands, 236 Ovaries, 242 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xiv xiv Contents Testes, 243 Other Hormones, 243 Mechanisms of Hormone Action, 244 Aging and the Endocrine System, 245 CHAPTER 11 Blood.........................................................250 Characteristics of Blood, 252 Plasma, 252 Blood Cells, 254 CHAPTER 12 The Heart...................................................272 Location and Pericardial Membranes, 274 Chambers—Vessels and Valves, 274 Coronary Vessels, 277 Cardiac Cycle and Heart Sounds, 278 Cardiac Conduction Pathway, 279 Heart Rate, 283 Cardiac Output, 283 Regulation of Heart Rate, 284 Aging and the Heart, 286 CHAPTER 13 The Vascular System.....................................290 Arteries, 292 Veins, 292 Capillaries, 293 Pathways of Circulation, 296 Velocity of Blood Flow, 306 Blood Pressure, 307 Regulation of Blood Pressure, 310 Aging and the Vascular System, 314 CHAPTER 14 The Lymphatic System and Immunity...............319 Lymph, 322 Lymph Vessels, 322 Lymphatic Tissue, 322 Immunity, 327 Aging and the Lymphatic System, 337 CHAPTER 15 The Respiratory System.................................342 Divisions of the Respiratory System, 344 Mechanism of Breathing, 347 Pulmonary Volumes, 351 Exchange of Gases, 354 Transport of Gases in the Blood, 355 Regulation of Respiration, 358 Respiration and Acid–Base Balance, 360 Aging and the Respiratory System, 361 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xv Contents xv CHAPTER 16 The Digestive System....................................367 Divisions of the Digestive System, 370 Types of Digestion, 370 Oral Cavity, 370 Pharynx, 373 Esophagus, 373 Structural Layers of the Alimentary Tube, 373 Stomach, 376 Small Intestine, 378 Liver, 379 Gallbladder, 379 Pancreas, 379 Completion of Digestion and Absorption, 381 Large Intestine, 385 Other Functions of the Liver, 386 Aging and the Digestive System, 389 CHAPTER 17 Body Temperature and Metabolism.................394 Body Temperature, 396 Metabolism, 400 Aging and Metabolism, 413 CHAPTER 18 The Urinary System......................................417 Kidneys, 421 Formation of Urine, 424 The Kidneys and Acid–Base Balance, 428 Other Functions of the Kidneys, 429 Elimination of Urine, 431 Characteristics of Urine, 432 Aging and the Urinary System, 433 CHAPTER 19 Fluid–Electrolyte and Acid–Base Balance...........439 Water Compartments, 442 Water Intake and Output, 443 Electrolytes, 445 Acid–Base Balance, 446 Aging and Fluid and pH Regulation, 450 CHAPTER 20 The Reproductive Systems.............................454 Meiosis, 456 Male Reproductive System, 457 Female Reproductive System, 462 Aging and the Reproductive Systems, 470 CHAPTER 21 Human Development and Genetics..................474 Human Development, 476 Genetics, 486 00Scanlon(p3)-FM 8/17/06 10:40 AM Page xvi xvi Contents CHAPTER 22 An Introduction to Microbiology and Human Disease......................................496 Classification of Microorganisms, 498 Normal Flora, 500 Infectious Disease, 500 Epidemiology, 503 Methods of Control of Microbes, 504 The Pathogens, 507 Appendixes..................................................528 A Units of Measure, 528 B Abbreviations, 530 C Normal Values for Some Commonly Used Blood Tests, 532 D Normal Values for Some Commonly Used Urine Tests, 533 E Eponymous Terms, 534 F Prefixes, Combining Word Roots, and Suffixes Used in Medical Terminology, 535 G Answers to the Illustration Questions, 539 Glossary......................................................547 Index..........................................................589 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 1 CHAPTER 1 Organization and General Plan of the Body 1 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 2 CHAPTER 1 Chapter Outline Student Objectives Levels of Organization Define the terms anatomy, physiology, and patho- Chemicals physiology. Use an example to explain how they are Cells related. Tissues Name the levels of organization of the body from Organs simplest to most complex, and explain each. Organ Systems Define the terms metabolism, metabolic rate, and Metabolism and Homeostasis homeostasis, and use examples to explain. Terminology and General Plan of the Body Explain how a negative feedback mechanism Body Parts and Areas works, and how a positive feedback mechanism Terms of Location and Position differs. Body Cavities and Their Membranes Describe the anatomic position. Dorsal cavity State the anatomic terms for the parts of the body. Ventral cavity Use proper terminology to describe the location Planes and Sections of body parts with respect to one another. Areas of the Abdomen Name the body cavities, their membranes, and some organs within each cavity. BOX 1–1 REPLACING TISSUES AND ORGANS Describe the possible sections through the body or BOX 1–2 VISUALIZING THE INTERIOR OF THE BODY an organ. Explain how and why the abdomen is divided into smaller areas. Be able to name organs in these areas. 2 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 3 Organization and General Plan of the Body New Terminology Related Clinical Terminology Anatomy (uh-NAT-uh-mee) Computed tomography (CT) scan Body cavity (BAH-dee KAV-i-tee) (kom-PEW-ted toh-MAH-grah-fee SKAN) Cell (SELL) Diagnosis (DYE-ag-NO-sis) Homeostasis (HOH-me-oh-STAY-sis) Disease (di-ZEEZ) Inorganic chemicals (IN-or-GAN-ik KEM-i-kuls) Magnetic resonance imaging (MRI) Meninges (me-NIN-jeez) (mag-NET-ik REZ-ah-nanse IM-ah-jing) Metabolism (muh-TAB-uh-lizm) Positron emission tomography (PET) Negative feedback (NEG-ah-tiv FEED-bak) (PAHZ-i-tron e-MISH-un toh-MAH-grah-fee) Organ (OR-gan) Organ system (OR-gan SIS-tem) Organic chemicals (or-GAN-ik KEM-i-kuls) Pathophysiology (PATH-oh-FIZZ-ee-AH-luh-jee) Pericardial membranes (PER-ee-KAR-dee-uhl MEM-brayns) Peritoneum/Mesentery (PER-i-toh-NEE-um/MEZ- en-TER-ee) Physiology (FIZZ-ee-AH-luh-jee) Plane (PLAYN) Pleural membranes (PLOOR-uhl MEM-brayns) Positive feedback (PAHS-ah-tiv FEED-bak) Section (SEK-shun) Tissue (TISH-yoo) Terms that appear in bold type in the chapter text are defined in the glossary, which begins on page 547. 3 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 4 4 Organization and General Plan of the Body T he human body is a precisely structured container of chemical reactions. Have you ever thought of your- that your knowledge of anatomy and physiology will become the basis for your further study in the health self in this way? Probably not, and yet, in the strictly professions. physical sense, that is what each of us is. The body consists of trillions of atoms in specific arrangements and thousands of chemical reactions proceeding in LEVELS OF ORGANIZATION a very orderly manner. That literally describes us, and yet it is clearly not the whole story. The keys The human body is organized into structural and to understanding human consciousness and self- functional levels of increasing complexity. Each higher awareness are still beyond our grasp. We do not yet level incorporates the structures and functions of the know what enables us to study ourselves—no other previous level, as you will see. We will begin with the animals do, as far as we know—but we have accumu- simplest level, which is the chemical level, and pro- lated a great deal of knowledge about what we are ceed to cells, tissues, organs, and organ systems. All of made of and how it all works. Some of this knowledge the levels of organization are depicted in Fig. 1–1. makes up the course you are about to take, a course in basic human anatomy and physiology. CHEMICALS Anatomy is the study of body structure, which The chemicals that make up the body may be divided includes size, shape, composition, and perhaps even into two major categories: inorganic and organic. coloration. Physiology is the study of how the body Inorganic chemicals are usually simple molecules functions. The physiology of red blood cells, for exam- made of one or two elements other than carbon (with ple, includes what these cells do, how they do it, and a few exceptions). Examples of inorganic chemicals are how this is related to the functioning of the rest of the water (H2O); oxygen (O2); one of the exceptions, car- body. Physiology is directly related to anatomy. For bon dioxide (CO2); and minerals such as iron (Fe), cal- example, red blood cells contain the mineral iron in cium (Ca), and sodium (Na). Organic chemicals are molecules of the protein called hemoglobin; this is an often very complex and always contain the elements aspect of their anatomy. The presence of iron enables carbon and hydrogen. In this category of organic red blood cells to carry oxygen, which is their function. chemicals are carbohydrates, fats, proteins, and All cells in the body must receive oxygen in order to nucleic acids. The chemical organization of the body function properly, so the physiology of red blood cells is the subject of Chapter 2. is essential to the physiology of the body as a whole. Pathophysiology is the study of disorders of func- CELLS tioning, and a knowledge of normal physiology makes such disorders easier to understand. For example, you The smallest living units of structure and function are are probably familiar with the anemia called iron- cells. There are many different types of human cells, deficiency anemia. With insufficient iron in the diet, though they all have certain similarities. Each type of there will not be enough iron in the hemoglobin of cell is made of chemicals and carries out specific red blood cells, and hence less oxygen will be trans- chemical reactions. Cell structure and function are ported throughout the body, resulting in the symp- discussed in Chapter 3. toms of the iron-deficiency disorder. This example shows the relationship between anatomy, physiology, TISSUES and pathophysiology. A tissue is a group of cells with similar structure and The purpose of this text is to enable you to gain function. There are four groups of tissues: an understanding of anatomy and physiology with the emphasis on normal structure and function. Many Epithelial tissues—cover or line body surfaces; some examples of pathophysiology have been included, are capable of producing secretions with specific however, to illustrate the relationship of disease to functions. The outer layer of the skin and sweat normal physiology and to describe some of the proce- glands are examples of epithelial tissues. Internal dures used in the diagnosis of disease. Many of the epithelial tissues include the walls of capillaries examples are clinical applications that will help you (squamous epithelium) and the kidney tubules begin to apply what you have learned and demonstrate (cuboidal epithelium), as shown in Fig. 1–1. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 5 1. Chemical Level 2. Cellular Level Cuboidal epithelium Squamous epithelium Smooth muscle 3. Tissue Level Kidney Urinary bladder 4. Organ Level Urinary system 6. Organism Level 5. Organ System Level Figure 1–1. Levels of structural organization of the human body, depicted from the simplest (chemical) to the most complex (organism). The organ system shown here is the urinary system. QUESTION: What other organ system seems to work directly with the urinary system? 5 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 6 6 Organization and General Plan of the Body Connective tissues—connect and support parts of and stomach. The kidneys contain several kinds of the body; some transport or store materials. Blood, epithelial, or surface tissues, for their work of absorp- bone, cartilage, and adipose tissue are examples of tion. The stomach is lined with epithelial tissue that this group. secretes gastric juice for digestion. Smooth muscle Muscle tissues—specialized for contraction, which tissue in the wall of the stomach contracts to mix brings about movement. Our skeletal muscles and food with gastric juice and propel it to the small intes- the heart are examples of muscle tissue. In Fig. 1–1, tine. Nerve tissue carries impulses that increase or you see smooth muscle tissue, which is found in decrease the contractions of the stomach (see Box 1–1: organs such as the urinary bladder and stomach. Replacing Tissues and Organs). Nerve tissue—specialized to generate and transmit ORGAN SYSTEMS electrochemical impulses that regulate body functions. The brain and optic nerves are examples of An organ system is a group of organs that all con- nerve tissue. tribute to a particular function. Examples are the urinary system, digestive system, and respiratory system. The types of tissues in these four groups, as well as In Fig. 1–1 you see the urinary system, which consists their specific functions, are the subject of Chapter 4. of the kidneys, ureters, urinary bladder, and urethra. These organs all contribute to the formation and ORGANS elimination of urine. An organ is a group of tissues precisely arranged so as As a starting point, Table 1–1 lists the organ sys- to accomplish specific functions. Examples of organs tems of the human body with their general functions, are the kidneys, individual bones, the liver, lungs, and some representative organs, and Fig. 1–2 depicts BOX 1–1 REPLACING TISSUES AND ORGANS Blood transfusions are probably the most familiar eventually be used to cover a large surface. Other and frequent form of “replacement parts” for peo- cells grown in culture include cartilage, bone, pan- ple. Blood is a tissue, and when properly typed and creas, and liver. Much research is being done on cross-matched (blood types will be discussed in liver implants (not transplants), clusters of func- Chapter 11) may safely be given to someone with tional liver cells grown in a lab. Such implants the same or a compatible blood type. would reduce or eliminate the need for human Organs, however, are much more complex struc- donors. Tissue engineering is also being used to cre- tures. When a patient receives an organ transplant, ate arteries and urinary bladders. there is always the possibility of rejection (destruc- Many artificial replacement parts have also been tion) of the organ by the recipient’s immune sys- developed. These are made of plastic or metal and tem (Chapter 14). With the discovery and use of are not rejected as foreign by the recipient’s more effective immune-suppressing medications, immune system. Damaged heart valves, for exam- however, the success rate for many types of organ ple, may be replaced by artificial ones, and sections transplants has increased. Organs that may be trans- of arteries may be replaced by tubular grafts made planted include corneas, kidneys, the heart, the of synthetic materials. Artificial joints are available liver, and the lungs. for every joint in the body, as is artificial bone for The skin is also an organ, but skin transplanted reconstructive surgery. Cochlear implants are tiny from another person will not survive very long. instruments that convert sound waves to electrical Several kinds of artificial skin are now available to impulses the brain can learn to interpret, and have temporarily cover large areas of damaged skin. provided some sense of hearing for people with cer- Patients with severe burns, for example, will even- tain types of deafness. Work is also progressing on tually need skin grafts from their own unburned the use of a featherweight computer chip as an arti- skin to form permanent new skin over the burn ficial retina, on devices that help damaged hearts sites. It is possible to “grow” a patient’s skin in lab- pump blood more efficiently, and on small, self- oratory culture, so that a small patch of skin may contained artificial hearts. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 7 Organization and General Plan of the Body 7 Table 1–1 THE ORGAN SYSTEMS System Functions Organs* Integumentary Is a barrier to pathogens and chemicals skin, subcutaneous tissue Prevents excessive water loss Skeletal Supports the body bones, ligaments Protects internal organs and red bone marrow Provides a framework to be moved by muscles Muscular Moves the skeleton muscles, tendons Produces heat Nervous Interprets sensory information brain, nerves, eyes, ears Regulates body functions such as movement by means of electrochemical impulses Endocrine Regulates body functions such as growth and reproduc- thyroid gland, pituitary tion by means of hormones gland, pancreas Regulates day-to-day metabolism by means of hormones Circulatory Transports oxygen and nutrients to tissues and removes heart, blood, arteries waste products Lymphatic Returns tissue fluid to the blood spleen, lymph nodes Destroys pathogens that enter the body and provides immunity Respiratory Exchanges oxygen and carbon dioxide between the air lungs, trachea, larynx, and blood diaphragm Digestive Changes food to simple chemicals that can be absorbed stomach, colon, liver, and used by the body pancreas Urinary Removes waste products from the blood kidneys, urinary bladder, Regulates volume and pH of blood and tissue fluid urethra Reproductive Produces eggs or sperm Female: ovaries, uterus In women, provides a site for the developing Male: testes, prostate gland embryo-fetus *These are simply representative organs, not an all-inclusive list. all of the organ systems. Some organs are part of two of life. The pumping of the heart, the digestion of organ systems; the pancreas, for example, is both a food in the stomach, the diffusion of gases in the lungs digestive and an endocrine organ, and the diaphragm and tissues, and the production of energy in each cell is part of both the muscular and respiratory systems. of the body are just a few of the thousands of aspects All of the organ systems make up an individual person. of metabolism. Metabolism comes from a Greek word The balance of this text discusses each system in more meaning “change,” and the body is always changing in detail. visible ways (walking down the street), microscopic ways (cells dividing in the skin to produce new epider- mis), and submicroscopic or molecular ways (RNA METABOLISM AND HOMEOSTASIS and enzymes constructing new proteins). A related concept, metabolic rate, is most often used to mean Metabolism is a collective noun; it is all of the chem- the speed at which the body produces energy and heat, ical reactions and physical processes that take place or, put another way, energy production per unit of within the body. Metabolism includes growing, repair- time, such as 24 hours. Metabolic rate, therefore, is ing, reacting, and reproducing—all the characteristics one aspect of metabolism. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 8 Muscular system Nervous system Skeletal system Integumentary system Circulatory system Figure 1–2. Organ systems. Compare the depiction of each system to its description in Table 1–1. QUESTION: Name at least one organ shown in each system. 8 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 9 Urinary system Endocrine system Respiratory system Digestive system Lymphatic system Reproductive system Figure 1–2. (Continued) 9 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 10 10 Organization and General Plan of the Body A person who is in good health may be said to be in heat production is detected by the brain and pituitary a state of homeostasis. Homeostasis reflects the abil- gland. They then decrease secretion of their hor- ity of the body to maintain a relatively stable metabo- mones, which in turn inhibits any further secretion of lism and to function normally despite many constant thyroxine until the metabolic rate decreases again. changes. The changes that are part of normal metab- Metabolic rate does rise and fall, but is kept within olism may be internal or external, and the body must normal limits. respond appropriately. You may be wondering if there is such a thing as a Eating breakfast, for example, brings about an positive feedback mechanism. There is, but they are internal change. Suddenly there is food in the stom- rare in the body and quite different from a negative ach, and something must be done with it. What hap- feedback mechanism. In a positive feedback mecha- pens? The food is digested or broken down into nism, the response to the stimulus does not stop or simple chemicals that the body can use. The protein in reverse the stimulus, but instead keeps the sequence of a hard-boiled egg is digested into amino acids, its basic events going. A good example is childbirth, in which chemical building blocks; these amino acids can then the sequence of events, simply stated, is as follows: be used by the cells of the body to produce their own Stretching of the uterine cervix stimulates secretion of specialized proteins. the hormone oxytocin by the posterior pituitary gland. An example of an external change is a rise in envi- Oxytocin stimulates contraction of the uterine muscle, ronmental temperature. On a hot day, the body tem- which causes more stretching, which stimulates more perature would also tend to rise. However, body oxytocin and, hence, more contractions. The mecha- temperature must be kept within its normal range of nism stops with the delivery of the baby and the pla- about 97! to 99!F (36! to 38!C) in order to support centa. This is the “brake,” the interrupting event. normal functioning. What happens? One of the body’s Any positive feedback mechanism requires an responses to the external temperature rise is to external “brake,” something to interrupt it. Blood increase sweating so that excess body heat can be lost clotting is such a mechanism, and without external by the evaporation of sweat on the surface of the skin. controls, clotting may become a vicious cycle of clot- This response, however, may bring about an undesir- ting and more clotting, doing far more harm than able internal change, dehydration. What happens? As good (discussed in Chapter 11). Inflammation follow- body water decreases, we feel the sensation of thirst ing an injury is beneficial and necessary for repair to and drink fluids to replace the water lost in sweating. begin, but the process may evolve into a cycle of dam- Notice that when certain body responses occur, they age and more damage. The rise of a fever may also reverse the event that triggered them. In the preced- trigger a positive feedback mechanism. Notice in Fig. ing example a rising body temperature stimulates 1–3 that bacteria have affected the body’s thermostat increased sweating, which lowers body temperature, in the hypothalamus and caused a fever. The rising which in turn decreases sweating. Unnecessary sweat- body temperature increases the metabolic rate, which ing that would be wasteful of water is prevented. This increases body temperature even more, becoming a is an example of a negative feedback mechanism, in cycle. Where is the inhibition, the brake? For this which the body’s response reverses the stimulus (in infection, the brake is white blood cells destroying the effect, turning it off for a while) and keeps some aspect bacteria that caused the fever. An interruption from of the body metabolism within its normal range. outside the cycle is necessary. It is for this reason, Look at Fig. 1–3 for another negative feedback because positive feedback mechanisms have the poten- mechanism, one in which the hormone thyroxine reg- tial to be self-perpetuating and cause harm, that they ulates the metabolic rate of the body. As metabolic are rare in the body. rate decreases, the hypothalamus (part of the brain) Negative feedback mechanisms, however, contain and pituitary gland detect this decrease and secrete their own brakes in that inhibition is a natural part of hormones to stimulate the thyroid gland (on the front the cycle, and the body has many of them. The secre- of the neck just below the larynx) to secrete the hor- tion of most hormones (Chapter 10) is regulated by mone thyroxine. Thyroxine stimulates the cellular negative feedback mechanisms. The regulation of enzyme systems that produce energy from food, which heart rate (Chapter 12) and blood pressure (Chapter increases the metabolic rate. The rise in energy and 13) involves several negative feedback mechanisms. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 11 Organization and General Plan of the Body 11 A Hypothalamus Thyroid gland and pituitary gland Cells decrease No longer Metabolic Thyroxine energy stimulates rate decreases production thyroid gland increases Hypothalamus and pituitary gland Thyroid gland Metabolic Stimulates Cells increase Thyroxine rate thyroid energy increases decreases gland production B Hypothalamus Cells increase Metabolic heat Fever rate production increases Heat gain Bacteria mechanisms White blood cells Key: Stimulates Inhibits Leads to Figure 1–3. Feedback mechanisms. (A) The negative feedback mechanism of regulation of metabolic rate by thyroxine. (B) The positive feedback mechanism triggered by a fever. See text for description. QUESTION: For each mechanism, where is the source of the “brake” or inhibition? The result of all of these mechanisms working to- of the human body, keep in mind that the proper func- gether is that all aspects of body functioning, that is, of tioning of each organ and organ system contributes to metabolism, are kept within normal limits, a steady homeostasis. Keep in mind as well that what we call state or equilibrium. This is homeostasis. the normal values of metabolism are often ranges, not In the chapters to come, you will find many more single numbers. Recall that normal body temperature examples of homeostasis. As you continue your study is a range: 97! to 99!F (36! to 38!C). Normal pulse 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 12 12 Organization and General Plan of the Body rate, another example, is 60 to 80 beats per minute; a Table 1–2 DESCRIPTIVE TERMS FOR normal respiratory rate is 12 to 20 breaths per minute. BODY PARTS AND AREAS Variations within the normal range are part of normal metabolism. Term Definition (Refers to) Antebrachial forearm Antecubital front of elbow TERMINOLOGY AND GENERAL Axillary armpit PLAN OF THE BODY Brachial upper arm Buccal (oral) mouth As part of your course in anatomy and physiology, Cardiac heart Cervical neck you will learn many new words or terms. At times you Cranial head may feel that you are learning a second language, and Cutaneous skin indeed you are. Each term has a precise meaning, Deltoid shoulder which is understood by everyone else who has learned Femoral thigh the language. Mastering the terminology of your pro- Frontal forehead Gastric stomach fession is essential to enable you to communicate effec- Gluteal buttocks tively with your coworkers and your future patients. Hepatic liver Although the number of new terms may seem a bit Iliac hip overwhelming at first, you will find that their use soon Inguinal groin becomes second nature to you. Lumbar small of back Mammary breast The terminology presented in this chapter will be Nasal nose used throughout the text in the discussion of the organ Occipital back of head systems. This will help to reinforce the meanings of Orbital eye these terms and will transform these new words into Parietal crown of head knowledge. Patellar kneecap Pectoral chest Pedal foot BODY PARTS AND AREAS Perineal pelvic floor Plantar sole of foot Each of the terms listed in Table 1–2 and shown in Popliteal back of knee Fig. 1–4 refers to a specific part or area of the body. Pulmonary lungs For example, the term femoral always refers to the Renal kidney thigh. The femoral artery is a blood vessel that passes Sacral base of spine through the thigh, and the quadriceps femoris is a Scapular shoulder blade Sternal breastbone large muscle group of the thigh. Temporal side of head Another example is pulmonary, which always refers Umbilical navel to the lungs, as in pulmonary artery, pulmonary edema, Volar (palmar) palm and pulmonary embolism. Although you may not know the exact meaning of each of these terms now, you do know that each has something to do with the lungs. these are pairs of terms and that each pair is a set of opposites. This will help you recall the terms and their TERMS OF LOCATION AND POSITION meanings. When describing relative locations, the body is always BODY CAVITIES AND assumed to be in anatomic position: standing upright THEIR MEMBRANES facing forward, arms at the sides with palms forward, and the feet slightly apart. The terms of location are The body has two major cavities: the dorsal cavity listed in Table 1–3, with a definition and example for (posterior) and the ventral cavity (anterior). Each of each. As you read each term, find the body parts used these cavities has further subdivisions, which are as examples in Figs. 1–4 and 1–5. Notice also that shown in Fig. 1–5. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 13 Organization and General Plan of the Body 13 Body Parts and Areas Anatomic position Cranial Frontal Parietal Orbital Temporal Nasal Occipital Buccal Cervical Sternal Deltoid Pectoral Scapular Axillary Mammary Brachial Antecubital Antebrachial Lumbar Umbilical Iliac Sacral Inguinal Femoral Gluteal Volar Perineal Popliteal Patellar Pedal Plantar A B Figure 1–4. Body parts and areas. The body is shown in anatomic position. (A) Anterior view. (B) Posterior view. (Compare with Table 1–2.) QUESTION: Name a body area that contains a bone with a similar name. Can you name two more? Dorsal Cavity Ventral Cavity The dorsal cavity contains the central nervous system, The ventral cavity consists of two compartments, the and consists of the cranial cavity and the vertebral or thoracic cavity and the abdominal cavity, which are spinal cavity. The dorsal cavity is a continuous one; separated by the diaphragm. The diaphragm is a large, that is, no wall or boundary separates its subdivisions. dome-shaped respiratory muscle. It has openings for The cranial cavity is formed by the skull and contains the esophagus and for large blood vessels, but other- the brain. The spinal cavity is formed by the backbone wise is a wall between the thoracic and abdominal cav- (spine) and contains the spinal cord. The membranes ities. The pelvic cavity may be considered a that line these cavities and cover the brain and spinal subdivision of the abdominal cavity (there is no wall cord are called the meninges. between them) or as a separate cavity. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 14 Table 1–3 TERMS OF LOCATION AND POSITION Term Definition Example Superior above, or higher The heart is superior to the liver. Inferior below, or lower The liver is inferior to the lungs. Anterior toward the front The chest is on the anterior side of the body. Posterior toward the back The lumbar area is posterior to the umbilical area. Ventral toward the front The mammary area is on the ventral side of the body. Dorsal toward the back The buttocks are on the dorsal side of the body. Medial toward the midline The heart is medial to the lungs. Lateral away from the midline The shoulders are lateral to the neck. Internal within, or interior to The brain is internal to the skull. External outside, or exterior to The ribs are external to the lungs. Superficial toward the surface The skin is the most superficial organ. Deep within, or interior to The deep veins of the legs are surrounded by muscles. Central the main part The brain is part of the central nervous system. Peripheral extending from the main part Nerves in the arm are part of the peripheral nervous system. Proximal closer to the origin The knee is proximal to the foot. Distal farther from the origin The palm is distal to the elbow. Parietal pertaining to the wall of a cavity The parietal pleura lines the chest cavity. Visceral pertaining to the organs within a cavity The visceral pleura covers the lungs. Cranial cavity Foramen magnum Dorsal cavity Spinal cavity Thoracic cavity Figure 1–5. Body cavities (lateral view from the left side). Diaphragm QUESTION: Which of these cavities are surrounded by bone? Ventral Abdominal cavity cavity Sacral promontory Pelvic cavity Symphysis pubis 14 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 15 Organization and General Plan of the Body 15 Organs in the thoracic cavity include the heart and folded around and covering the outer surfaces of the lungs. The membranes of the thoracic cavity are abdominal organs. serous membranes called the pleural membranes. The pelvic cavity is inferior to the abdominal cav- The parietal pleura lines the chest wall, and the vis- ity. Although the peritoneum does not line the pelvic ceral pleura covers the lungs. The heart has its own set cavity, it covers the free surfaces of several pelvic of serous membranes called the pericardial mem- organs. Within the pelvic cavity are the urinary blad- branes. The parietal pericardium lines the fibrous der and reproductive organs such as the uterus in pericardial sac, and the visceral pericardium covers the women and the prostate gland in men. heart muscle. Organs in the abdominal cavity include the liver, PLANES AND SECTIONS stomach, and intestines. The membranes of the abdominal cavity are also serous membranes called the When internal anatomy is described, the body or an peritoneum and mesentery. The peritoneum is the organ is often cut or sectioned in a specific way so as membrane that lines the entire abdominal wall, and to make particular structures easily visible. A plane is the mesentery is the continuation of this membrane, an imaginary flat surface that separates two portions of - B A Figure 1–6. (A) Planes and sections of the body. (B) Cross-section and longitudinal section of the small intestine. QUESTION: What other organs would have sections that look like those of the small intestine? 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 16 16 Organization and General Plan of the Body Front Stomach Liver Pancreas Gallbladder Colon Duodenum Spleen Ribs Aorta Left kidney Vertebra Inferior vena cava Spinal cord Right kidney Back Muscle C Figure 1–6. (Continued) (C) Transverse section through the upper abdomen. the body or an organ. These planes and sections are cian or nurse would want to know more precisely shown in Fig. 1–6 (see Box 1–2: Visualizing the where the pain was. To determine this, the abdomen Interior of the Body). may be divided into smaller regions or areas, which are shown in Fig. 1–7. Frontal (coronal) section—a plane from side to side separates the body into front and back portions. Quadrants—a transverse plane and a midsagittal Sagittal section—a plane from front to back separates plane that cross at the umbilicus will divide the the body into right and left portions. A midsagittal abdomen into four quadrants. Clinically, this is section creates equal right and left halves. probably the division used more frequently. The pain of gallstones might then be described as in the Transverse section—a horizontal plane separates the right upper quadrant. body into upper and lower portions. Nine areas—two transverse planes and two sagittal Cross-section—a plane perpendicular to the long planes divide the abdomen into nine areas: axis of an organ. A cross-section of the small intes- Upper areas—above the level of the rib cartilages are tine (which is a tube) would look like a circle with the left hypochondriac, epigastric, and right the cavity of the intestine in the center. hypochondriac. Longitudinal section—a plane along the long axis of Middle areas—the left lumbar, umbilical, and right an organ. A longitudinal section of the intestine is lumbar. shown in Fig. 1–6, and a frontal section of the Lower areas—below the level of the top of the pelvic femur (thigh bone) would also be a longitudinal bone are the left iliac, hypogastric, and right section (see Fig. 6–1 in Chapter 6). iliac. These divisions are often used in anatomic studies AREAS OF THE ABDOMEN to describe the location of organs. The liver, for exam- The abdomen is a large area of the lower trunk of the ple, is located in the epigastric and right hypochon- body. If a patient reported abdominal pain, the physi- driac areas. 01Scanlon(p3)-ch01 8/17/06 10:41 AM Page 17 Organization and General Plan of the Body 17 A B Figure 1–7. Areas of the abdomen. (A) Four quadrants. (B) Nine regions. QUESTION: Are there any organs found in all four abdominal quadrants? nal changes. In the chapters that follow, you will find SUMMARY detailed descriptions of the physiology of each organ As you will see, the terminology presented in this and organ system, and how the metabolism of each is chapter is used throughout the text to describe the necessary to homeostasis. We will now return to a anatomy of organs and the names of their parts. All consideration of the structural organization of the organs of the body contribute

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