The ninth edition of this classic text has been entrusted into the capable hands of a dynamic new team of authors, who have taken on the challenge of maintaining the strengths and reputation that have long been the book's hallmark. The fundamental purpose of this textbook has stayed the same: to present the principles and facts of human physiology in a format that is suitable for undergraduates regardless of academic background or field of study. The book carries on the tradition of clarity and accuracy, while refining and updating the content to meet the needs of today's instructors and students. The ninth edition features a streamlined, clinically oriented focus to the study of human body systems. - In response to reviewers' requests, the authors have added new clinically-related content in nearly every chapter. Also, the science has been carefully updated line by line, to ensure that students are presented with the latest research. - Building on the dynamic art program of the 8th edition, the authors have revised and added many new illustrations and photographs (about 100), many of which illustrate diseases or clinical treatments. - The explanation of resting and action potentials, a difficult topic for novice readers, has been re-written to emphasize the importance and use of the Nernst equation (formerly included as an appendix) in understanding how ions move across membranes.