Human Anatomy and Physiology is designed for the two-semester anatomy and physiology course taken by life science and allied health students. The textbook follows the scope and sequence of most Human Anatomy and Physiology courses, and its coverage and organization were informed by hundreds of instructors who teach the course. Instructors can customize the book, adapting it to the approach that works best in their classroom. The artwork for this textbook is aimed focusing student learning through a powerful blend of traditional depictions and instructional innovations. Color is used sparingly, to emphasize the most important aspects of any given illustration. Significant use of micrographs from the University of Michigan complement the illustrations, and provide the students with a meaningful alternate depiction of each concept. Finally, enrichment elements provide relevance and deeper context for students, particularly in the areas of health, disease, and information relevant to their intended careers.

Welcome to Anatomy and Physiology, an OpenStax resource. This textbook was written to increase student access to high-quality learning materials, maintaining highest standards of academic rigor at little to no cost.

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About Anatomy and Physiology

Coverage and Scope

The units of our Anatomy and Physiology textbook adhere to the scope and sequence followed by most two-semester courses nationwide. The development choices for this textbook were made with the guidance of hundreds of faculty who are deeply involved in teaching this course. These choices led to innovations in art, terminology, career orientation, practical applications, and multimedia-based learning, all with a goal of increasing relevance to students. We strove to make the discipline meaningful and memorable to students, so that they can draw from it a working knowledge that will enrich their future studies.

Unit 1: Levels of Organization

Chapters 1–4 provide students with a basic understanding of human anatomy and physiology, including its language, the levels of organization, and the basics of chemistry and cell biology. These chapters provide a foundation for the further study of the body. They also focus particularly on how the body’s regions, important chemicals, and cells maintain homeostasis.* * *

Chapter 1 An Introduction to the Human Body* * *

Chapter 2 The Chemical Level of Organization* * *

Chapter 3 The Cellular Level of Organization* * *

Chapter 4 The Tissue Level of Organization* * *

Unit 2: Support and Movement

In Chapters 5–11, students explore the skin, the largest organ of the body, and examine the body’s skeletal and muscular systems, following a traditional sequence of topics. This unit is the first to walk students through specific systems of the body, and as it does so, it maintains a focus on homeostasis as well as those diseases and conditions that can disrupt it.* * *

Chapter 5 The Integumentary System* * *

Chapter 6 Bone and Skeletal Tissue* * *

Chapter 7 The Axial Skeleton* * *

Chapter 8 The Appendicular Skeleton* * *

Chapter 9 Joints* * *

Chapter 10 Muscle Tissue* * *

Chapter 11 The Muscular System* * *

Unit 3: Regulation, Integration, and Control

Chapters 12–17 help students answer questions about nervous and endocrine system control and regulation. In a break with the traditional sequence of topics, the special senses are integrated into the chapter on the somatic nervous system. The chapter on the neurological examination offers students a unique approach to understanding nervous system function using five simple but powerful diagnostic tests. * * *

Chapter 12 Introduction to the Nervous System* * *

Chapter 13 The Anatomy of the Nervous System* * *

Chapter 14 The Somatic Nervous System* * *

Chapter 15 The Autonomic Nervous System* * *

Chapter 16 The Neurological Exam* * *

Chapter 17 The Endocrine System* * *

Unit 4: Fluids and Transport

In Chapters 18–21, students examine the principal means of transport for materials needed to support the human body, regulate its internal environment, and provide protection. * * *

Chapter 18 Blood* * *

Chapter 19 The Cardiovascular System: The Heart* * *

Chapter 20 The Cardiovascular System: Blood Vessels and Circulation* * *

Chapter 21 The Lymphatic System and Immunity

Unit 5: Energy, Maintenance, and Environmental Exchange

In Chapters 22–26, students discover the interaction between body systems and the outside environment for the exchange of materials, the capture of energy, the release of waste, and the overall maintenance of the internal systems that regulate the exchange. The explanations and illustrations are particularly focused on how structure relates to function. * * *

Chapter 22 The Respiratory System* * *

Chapter 23 The Digestive System* * *

Chapter 24 Nutrition and Metabolism* * *

Chapter 25 The Urinary System* * *

Chapter 26 Fluid, Electrolyte, and Acid–Base Balance* * *

Unit 6: Human Development and the Continuity of Life

The closing chapters examine the male and female reproductive systems, describe the process of human development and the different stages of pregnancy, and end with a review of the mechanisms of inheritance. * * *

Chapter 27 The Reproductive System* * *

Chapter 28 Development and Genetic Inheritance* * *

Pedagogical Foundation and Features

Anatomy and Physiology is designed to promote scientific literacy. Throughout the text, you will find features that engage the students by taking selected topics a step further.

Dynamic, Learner-Centered Art

Our unique approach to visuals is designed to emphasize only the components most important in any given illustration. The art style is particularly aimed at focusing student learning through a powerful blend of traditional depictions and instructional innovations.

Much of the art in this book consists of black line illustrations. The strongest line is used to highlight the most important structures, and shading is used to show dimension and shape. Color is used sparingly to highlight and clarify the primary anatomical or functional point of the illustration. This technique is intended to draw students’ attention to the critical learning point in the illustration, without distraction from excessive gradients, shadows, and highlights. Full color is used when the structure or process requires it (for example, muscle diagrams and cardiovascular system illustrations).

A color illustration of the pharynx.


Micrograph magnifications have been calculated based on the objective provided with the image. If a micrograph was recorded at 40×, and the image was magnified an additional 2×, we calculated the final magnification of the micrograph to be 80×.

Please note that, when viewing the textbook electronically, the micrograph magnification provided in the text does not take into account the size and magnification of the screen on your electronic device. There may be some variation.

A color illustration of the pharynx.

Additional Resources

Student and Instructor Resources

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Partner Resources

OpenStax Partners are our allies in the mission to make high-quality learning materials affordable and accessible to students and instructors everywhere. Their tools integrate seamlessly with our OpenStax titles at a low cost. To access the partner resources for your text, visit your book page on

About the Authors

Senior Contributing Authors

J. Gordon Betts, Tyler Junior College* * *

Peter Desaix, University of North Carolina at Chapel Hill* * *

Eddie Johnson, Central Oregon Community College* * *

Jody E. Johnson, Arapahoe Community College* * *

Oksana Korol, Aims Community College* * *

Dean Kruse, Portland Community College* * *

Brandon Poe, Springfield Technical Community College* * *

James A. Wise, Hampton University* * *

Mark Womble, Youngstown State University* * *

Kelly A. Young, California State University, Long Beach


Robin J. Heyden

Contributing Authors

Kim Aaronson, Aquarius Institute; Triton College* * *

Lopamudra Agarwal, Augusta Technical College* * *

Gary Allen, Dalhousie University* * *

Robert Allison, McLennan Community College* * *

Heather Armbruster, Southern Union State Community College* * *

Timothy Ballard, University of North Carolina Wilmington* * *

Matthew Barlow, Eastern New Mexico University* * *

William Blaker, Furman University* * *

Julie Bowers, East Tennessee State University* * *

Emily Bradshaw, Florida Southern College* * *

Nishi Bryska, University of North Carolina, Charlotte* * *

Susan Caley Opsal, Illinois Valley Community College* * *

Boyd Campbell, Southwest College of Naturopathic Medicine and Health Sciences* * *

Ann Caplea, Walsh University* * *

Marnie Chapman, University of Alaska, Sitka* * *

Barbara Christie-Pope, Cornell College* * *

Kenneth Crane, Texarkana College* * *

Maurice Culver, Florida State College at Jacksonville* * *

Heather Cushman, Tacoma Community College* * *

Noelle Cutter, Molloy College* * *

Lynnette Danzl-Tauer, Rock Valley College* * *

Jane Davis, Aurora University* * *

AnnMarie DelliPizzi, Dominican College* * *

Susan Dentel, Washtenaw Community College* * *

Pamela Dobbins, Shelton State Community College* * *

Patty Dolan, Pacific Lutheran University* * *

Sondra Dubowsky, McLennan Community College* * *

Peter Dukehart, Three Rivers Community College* * *

Ellen DuPré, Central College* * *

Elizabeth DuPriest, Warner Pacific College* * *

Pam Elf, University of Minnesota* * *

Sharon Ellerton, Queensborough Community College* * *

Carla Endres, Utah State University - College of Eastern Utah: San Juan Campus* * *

Myriam Feldman, Lake Washington Institute of Technology; Cascadia Community College* * *

Greg Fitch, Avila University* * *

Lynn Gargan, Tarant County College* * *

Michael Giangrande, Oakland Community College* * *

Chaya Gopalan, St. Louis College of Pharmacy* * *

Victor Greco, Chattahoochee Technical College* * *

Susanna Heinze, Skagit Valley College* * *

Ann Henninger, Wartburg College* * *

Dale Horeth, Tidewater Community College* * *

Michael Hortsch, University of Michigan* * *

Rosemary Hubbard, Marymount University* * *

Mark Hubley, Prince George's Community College* * *

Branko Jablanovic, College of Lake County* * *

Norman Johnson, University of Massachusetts Amherst* * *

Mark Jonasson, North Arkansas College* * *

Jeff Keyte, College of Saint Mary* * *

William Kleinelp, Middlesex County College* * *

Leigh Kleinert, Grand Rapids Community College* * *

Brenda Leady, University of Toledo* * *

John Lepri, University of North Carolina, Greensboro* * *

Sarah Leupen, University of Maryland, Baltimore County* * *

Lihua Liang, Johns Hopkins University* * *

Robert Mallet, University of North Texas Health Science Center* * *

Bruce Maring, Daytona State College* * *

Elisabeth Martin, College of Lake County* * *

Natalie Maxwell, Carl Albert State College, Sallisaw* * *

Julie May, William Carey University* * *

Debra McLaughlin, University of Maryland University College* * *

Nicholas Mitchell, St. Bonaventure University* * *

Shobhana Natarajan, Brookhaven College* * *

Phillip Nicotera, St. Petersburg College* * *

Mary Jane Niles, University of San Francisco* * *

Ikemefuna Nwosu, Parkland College; Lake Land College* * *

Betsy Ott, Tyler Junior College* * *

Ivan Paul, John Wood Community College* * *

Aaron Payette, College of Southern Nevada* * *

Scott Payne, Kentucky Wesleyan College* * *

Cameron Perkins, South Georgia College* * *

David Pfeiffer, University of Alaska, Anchorage* * *

Thomas Pilat, Illinois Central College* * *

Eileen Preston, Tarrant County College* * *

Mike Pyle, Olivet Nazarene University* * *

Robert Rawding, Gannon University* * *

Jason Schreer, State University of New York at Potsdam* * *

Laird Sheldahl, Mt. Hood Community College* * *

Brian Shmaefsky, Lone Star College System* * *

Douglas Sizemore, Bevill State Community College* * *

Susan Spencer, Mount Hood Community College* * *

Cynthia Standley, University of Arizona* * *

Robert Sullivan, Marist College* * *

Eric Sun, Middle Georgia State College* * *

Tom Swenson, Ithaca College* * *

Kathleen Tallman, Azusa Pacific University* * *

Rohinton Tarapore, University of Pennsylvania* * *

Elizabeth Tattersall, Western Nevada College* * *

Mark Thomas, University of Northern Colorado* * *

Janis Thompson, Lorain County Community College* * *

Rita Thrasher, Pensacola State College* * *

David Van Wylen, St. Olaf College* * *

Lynn Wandrey, Mott Community College* * *

Margaret Weck, St. Louis College of Pharmacy* * *

Kathleen Weiss, George Fox University* * *

Neil Westergaard, Williston State College* * *

David Wortham, West Georgia Technical College* * *

Umesh Yadav, University of Texas Medical Branch* * *

Tony Yates, Oklahoma Baptist University* * *

Justin York, Glendale Community College* * *

Cheri Zao, North Idaho College* * *

Elena Zoubina, Bridgewater State University; Massasoit Community College* * *

Shobhana Natarajan, Alcon Laboratories, Inc.

Special Thanks

OpenStax wishes to thank the Regents of University of Michigan Medical School for the use of their extensive micrograph collection. Many of the UM micrographs that appear in Anatomy and Physiology are interactive WebScopes, which students can explore by zooming in and out.

We also wish to thank the Open Learning Initiative at Carnegie Mellon University, with whom we shared and exchanged resources during the development of Anatomy and Physiology.

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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