In new CBME program, competency map has been provided by NMC for each subject. Competency map in the tabular format with reference to chapter and page number and citation of competency code inside the relevant places in text, have been provided in this new edition. Clinical application and applied aspects have been made more updated and revised. More numbers of ‘Clinical Notes’ and ‘Important Notes’ have been added to this edition, to make the student understand the physiological basis of clinical applications in medicine. New topics of Physiology of Stress, Physiology of Yoga and Meditation, Brain Death, Glucose Homeostasis and Pathophysiology of Diabetes and Body Fluid Volume Homeostasis, and Clinical Case Scenarios have been added to this edition. Physiology is a rapidly advancing subject. All major concepts and advances in physiology have been thoroughly incorporated in the text. The presentation of the texts, especially to explain key concepts have been made more structured with more point-wise (bulleted) description. Multiple choice questions (MCQs) that are part of all kinds of assessments have been thoroughly reviewed and new clinical-based and application-based MCQs have been added in this new edition.