Physiology Cases and Problems, Fourth Edition is a collection of carefully selected patient case studies that cover the clinically relevant physiology topics that first and second year medical students need to know for physiology coursework and for the USMLE Step 1. Organized by body system, the book presents cases studies with questions and problems, followed by complete explanations and solutions including diagrams, graphs, and charts. Students may use this book alone, in small groups, or as a complement to Dr. Costanzo's BRS Physiology, Fifth Edition. Either way, it is intended to be a dynamic, working book that challenges its users to think more critically about physiologic principles.