A postgraduate student in physiology, preparing for his future role as a teacher and research worker, has to attain a higher degree of depth and proficiency in the subject. The textbooks of physiology alone are not sufficient for this purpose. Though excellent review articles are available to fulfil this requirement, with the limited time available the postgraduate students cannot be expected to read 50–100 page review articles with over a hundred references each, and make comprehensive and concise summaries of the contents. This book attempts to fill this lacuna in the postgraduate medical education in physiology. Basically, each chapter in the book is the latest review article on the subject but is presented in a textbook format. Information culled from scores of review articles and original articles has been distilled and condensed in approximately 10-page write up. Besides postgraduate students, members of faculty in physiology department would also find this book a simple path for updating their knowledge on the subject. The book has the hallmark of the author’s previous books in physiology, namely conciseness and simplicity of presentation. A large number of simple illustrations helps to clarify the text.