Susan J. Hall, PhD, FACSM Professor Emerita of Kinesiology and Applied Physiology University of Delaware Michelle A. Provost-Craig, PhD Associate Professor of Kinesiology and Applied Physiology University of Delaware William C. Rose, PhD Associate Professor of Kinesiology and Applied Physiology University of Delaware Publisher The Goodheart-Willcox Company, Inc. Tinley Park, Illinois www.g-w.com Anatomy & Physiology Essentials S E C O N D E D I T I O N