The human structure and functions is an integrative course explaining the normal morphological structure and life activity rules of the human body, the process of disease occurrence and development, and the principles of drug-body interactions. It covers four main aspects, namely, normal morphological structure and its occurrence, normal life activities and their rules, changes in human body structure and functions under pathological circumstances as well as symptoms and signs that may occur, and how drugs take effect within the human body and its mechanisms. Through studying this book, readers can gain a preliminary understanding of the normal morphological structure and activity rules of the human body, the process of disease occurrence and development, common symptoms and signs, and disease prevention and treatment, which lays a solid foundation for subsequent integrated courses on organ systems.